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<button class="button is-small is-link">Go</button> </div> </div> </form> </div> </div> <nav class="pagination is-small is-centered breathe-horizontal" role="navigation" aria-label="pagination"> <a href="" class="pagination-previous is-invisible">Previous </a> <a href="/search/?searchtype=author&query=Peng%2C+C&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Peng%2C+C&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=Peng%2C+C&start=50" class="pagination-link " aria-label="Page 2" aria-current="page">2 </a> </li> <li> <a href="/search/?searchtype=author&query=Peng%2C+C&start=100" class="pagination-link " aria-label="Page 3" aria-current="page">3 </a> </li> </ul> </nav> <ol class="breathe-horizontal" start="1"> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2502.09681">arXiv:2502.09681</a> <span> [<a href="https://arxiv.org/pdf/2502.09681">pdf</a>, <a href="https://arxiv.org/format/2502.09681">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Theory">hep-th</span> </div> </div> <p class="title is-5 mathjax"> Graph-Theoretic Analysis of $n$-Replica Time Evolution in the Brownian Gaussian Unitary Ensemble </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+T">Tingfei Li</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Cheng Peng</a>, <a href="/search/quant-ph?searchtype=author&query=Yu%2C+J">Jianghui Yu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2502.09681v1-abstract-short" style="display: inline;"> In this paper, we investigate the $n$-replica time evolution operator $\mathcal{U}_n(t)\equiv e^{\mathcal{L}_nt} $ for the Brownian Gaussian Unitary Ensemble (BGUE) using a graph-theoretic approach. We examine the moments of the generating operator $\mathcal{L}_n$, which governs the Euclidean time evolution within an auxiliary $D^{2n}$-dimensional Hilbert space, where $D$ represents the dimension… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.09681v1-abstract-full').style.display = 'inline'; document.getElementById('2502.09681v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2502.09681v1-abstract-full" style="display: none;"> In this paper, we investigate the $n$-replica time evolution operator $\mathcal{U}_n(t)\equiv e^{\mathcal{L}_nt} $ for the Brownian Gaussian Unitary Ensemble (BGUE) using a graph-theoretic approach. We examine the moments of the generating operator $\mathcal{L}_n$, which governs the Euclidean time evolution within an auxiliary $D^{2n}$-dimensional Hilbert space, where $D$ represents the dimension of the Hilbert space for the original system. Explicit representations for the cases of $n = 2$ and $n = 3$ are derived, emphasizing the role of graph categorization in simplifying calculations. Furthermore, we present a general approach to streamline the calculation of time evolution for arbitrary $n$, supported by a detailed example of $n = 4$. Our results demonstrate that the $n$-replica framework not only facilitates the evaluation of various observables but also provides valuable insights into the relationship between Brownian disordered systems and quantum information theory. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.09681v1-abstract-full').style.display = 'none'; document.getElementById('2502.09681v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 13 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2025. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">32 pages, 3 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2412.13849">arXiv:2412.13849</a> <span> [<a href="https://arxiv.org/pdf/2412.13849">pdf</a>, <a href="https://arxiv.org/format/2412.13849">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> 99.9%-fidelity in measuring a superconducting qubit </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wang%2C+C">Can Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+F">Feng-Ming Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+H">He Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Du%2C+Y">Yi-Fei Du</a>, <a href="/search/quant-ph?searchtype=author&query=Ying%2C+C">Chong Ying</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+J">Jian-Wen Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Huo%2C+Y">Yong-Heng Huo</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Cheng-Zhi Peng</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+X">Xiaobo Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+M">Ming-Cheng Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Lu%2C+C">Chao-Yang Lu</a>, <a href="/search/quant-ph?searchtype=author&query=Pan%2C+J">Jian-Wei Pan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2412.13849v2-abstract-short" style="display: inline;"> Despite the significant progress in superconducting quantum computation over the past years, quantum state measurement still lags nearly an order of magnitude behind quantum gate operations in speed and fidelity. The main challenge is that the strong coupling and readout signal used to probe the quantum state may also introduce additional channels which may cause qubit state transitions. Here, we… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.13849v2-abstract-full').style.display = 'inline'; document.getElementById('2412.13849v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.13849v2-abstract-full" style="display: none;"> Despite the significant progress in superconducting quantum computation over the past years, quantum state measurement still lags nearly an order of magnitude behind quantum gate operations in speed and fidelity. The main challenge is that the strong coupling and readout signal used to probe the quantum state may also introduce additional channels which may cause qubit state transitions. Here, we design a novel architecture to implement the long-sought longitudinal interaction scheme between qubits and resonators. This architecture not only provides genuine longitudinal interaction by eliminating residual transversal couplings, but also introduces proper nonlinearity to the resonator that can further minimize decay error and measurement-induced excitation error. Our experimental results demonstrate a measurement fidelity of 99.8% in 202 ns without the need for any first-stage amplification. After subtracting the residual preparation errors, the pure measurement fidelity is above 99.9%. Our scheme is compatible with the multiplexing readout scheme and can be used for quantum error correction. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.13849v2-abstract-full').style.display = 'none'; document.getElementById('2412.13849v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 19 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 18 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2412.11924">arXiv:2412.11924</a> <span> [<a href="https://arxiv.org/pdf/2412.11924">pdf</a>, <a href="https://arxiv.org/format/2412.11924">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Establishing a New Benchmark in Quantum Computational Advantage with 105-qubit Zuchongzhi 3.0 Processor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Gao%2C+D">Dongxin Gao</a>, <a href="/search/quant-ph?searchtype=author&query=Fan%2C+D">Daojin Fan</a>, <a href="/search/quant-ph?searchtype=author&query=Zha%2C+C">Chen Zha</a>, <a href="/search/quant-ph?searchtype=author&query=Bei%2C+J">Jiahao Bei</a>, <a href="/search/quant-ph?searchtype=author&query=Cai%2C+G">Guoqing Cai</a>, <a href="/search/quant-ph?searchtype=author&query=Cai%2C+J">Jianbin Cai</a>, <a href="/search/quant-ph?searchtype=author&query=Cao%2C+S">Sirui Cao</a>, <a href="/search/quant-ph?searchtype=author&query=Zeng%2C+X">Xiangdong Zeng</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+F">Fusheng Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+J">Jiang Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+K">Kefu Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+X">Xiawei Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+X">Xiqing Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Z">Zhe Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Z">Zhiyuan Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Z">Zihua Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chu%2C+W">Wenhao Chu</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+H">Hui Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+Z">Zhibin Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Ding%2C+P">Pei Ding</a>, <a href="/search/quant-ph?searchtype=author&query=Ding%2C+X">Xun Ding</a>, <a href="/search/quant-ph?searchtype=author&query=Ding%2C+Z">Zhuzhengqi Ding</a>, <a href="/search/quant-ph?searchtype=author&query=Dong%2C+S">Shuai Dong</a>, <a href="/search/quant-ph?searchtype=author&query=Dong%2C+Y">Yupeng Dong</a>, <a href="/search/quant-ph?searchtype=author&query=Fan%2C+B">Bo Fan</a> , et al. (129 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2412.11924v1-abstract-short" style="display: inline;"> In the relentless pursuit of quantum computational advantage, we present a significant advancement with the development of Zuchongzhi 3.0. This superconducting quantum computer prototype, comprising 105 qubits, achieves high operational fidelities, with single-qubit gates, two-qubit gates, and readout fidelity at 99.90%, 99.62% and 99.18%, respectively. Our experiments with an 83-qubit, 32-cycle r… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.11924v1-abstract-full').style.display = 'inline'; document.getElementById('2412.11924v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.11924v1-abstract-full" style="display: none;"> In the relentless pursuit of quantum computational advantage, we present a significant advancement with the development of Zuchongzhi 3.0. This superconducting quantum computer prototype, comprising 105 qubits, achieves high operational fidelities, with single-qubit gates, two-qubit gates, and readout fidelity at 99.90%, 99.62% and 99.18%, respectively. Our experiments with an 83-qubit, 32-cycle random circuit sampling on Zuchongzhi 3.0 highlight its superior performance, achieving one million samples in just a few hundred seconds. This task is estimated to be infeasible on the most powerful classical supercomputers, Frontier, which would require approximately $6.4\times 10^9$ years to replicate the task. This leap in processing power places the classical simulation cost six orders of magnitude beyond Google's SYC-67 and SYC-70 experiments [Nature 634, 328(2024)], firmly establishing a new benchmark in quantum computational advantage. Our work not only advances the frontiers of quantum computing but also lays the groundwork for a new era where quantum processors play an essential role in tackling sophisticated real-world challenges. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.11924v1-abstract-full').style.display = 'none'; document.getElementById('2412.11924v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2412.05542">arXiv:2412.05542</a> <span> [<a href="https://arxiv.org/pdf/2412.05542">pdf</a>, <a href="https://arxiv.org/format/2412.05542">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Instrumentation and Detectors">physics.ins-det</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> 113 km absolute ranging with nanometer precision </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Y">Yan-Wei Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Lian%2C+M">Meng-Zhe Lian</a>, <a href="/search/quant-ph?searchtype=author&query=Han%2C+J">Jin-Jian Han</a>, <a href="/search/quant-ph?searchtype=author&query=Zeng%2C+T">Ting Zeng</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+M">Min Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wei%2C+G">Guo-Dong Wei</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Y">Yong Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Sheng%2C+Y">Yi Sheng</a>, <a href="/search/quant-ph?searchtype=author&query=Esamdin%2C+A">Ali Esamdin</a>, <a href="/search/quant-ph?searchtype=author&query=Hou%2C+L">Lei Hou</a>, <a href="/search/quant-ph?searchtype=author&query=Shen%2C+Q">Qi Shen</a>, <a href="/search/quant-ph?searchtype=author&query=Guan%2C+J">Jian-Yu Guan</a>, <a href="/search/quant-ph?searchtype=author&query=Jia%2C+J">Jian-Jun Jia</a>, <a href="/search/quant-ph?searchtype=author&query=Ren%2C+J">Ji-Gang Ren</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Cheng-Zhi Peng</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Q">Qiang Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Jiang%2C+H">Hai-Feng Jiang</a>, <a href="/search/quant-ph?searchtype=author&query=Pan%2C+J">Jian-Wei Pan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2412.05542v1-abstract-short" style="display: inline;"> Accurate long-distance ranging is crucial for diverse applications, including satellite formation flying, very-long-baseline interferometry, gravitational-wave observatory, geographical research, etc. The integration of the time-of-flight mesurement with phase interference in dual-comb method enables high-precision ranging with a rapid update rate and an extended ambiguity range. Pioneering experi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.05542v1-abstract-full').style.display = 'inline'; document.getElementById('2412.05542v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.05542v1-abstract-full" style="display: none;"> Accurate long-distance ranging is crucial for diverse applications, including satellite formation flying, very-long-baseline interferometry, gravitational-wave observatory, geographical research, etc. The integration of the time-of-flight mesurement with phase interference in dual-comb method enables high-precision ranging with a rapid update rate and an extended ambiguity range. Pioneering experiments have demonstrated unprecedented precision in ranging, achieving 5 nm @ 60 ms for 1.1 m and 200 nm @ 0.5 s for 25 m. However, long-distance ranging remains technically challenging due to high transmission loss and noise. In this letter, we propose a two-way dual-comb ranging (TWDCR) approach that enables successful ranging over a distance of 113 kilometers. We employ air dispersion analysis and synthetic repetition rate technique to extend the ambiguity range of the inherently noisy channel beyond 100 km. The achieved ranging precision is 11.5 $渭$m @ 1.3 ms, 681 nm @ 1 s, and 82 nm @ 21 s, as confirmed through a comparative analysis of two independent systems. The advanced long-distance ranging technology is expected to have immediate implications for space research initiatives, such as the space telescope array and the satellite gravimetry. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.05542v1-abstract-full').style.display = 'none'; document.getElementById('2412.05542v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 7 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">21 pages, 5 figures, 1 table</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.12806">arXiv:2411.12806</a> <span> [<a href="https://arxiv.org/pdf/2411.12806">pdf</a>, <a href="https://arxiv.org/format/2411.12806">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Theory">hep-th</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Statistical Mechanics">cond-mat.stat-mech</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> D-commuting SYK model: building quantum chaos from integrable blocks </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Gao%2C+P">Ping Gao</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+H">Han Lin</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Cheng Peng</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2411.12806v2-abstract-short" style="display: inline;"> We construct a new family of quantum chaotic models by combining multiple copies of integrable commuting SYK models. As each copy of the commuting SYK model does not commute with others, this construction breaks the integrability of each commuting SYK and the family of models demonstrates the emergence of quantum chaos. We study the spectrum of this model analytically in the double-scaled limit. A… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.12806v2-abstract-full').style.display = 'inline'; document.getElementById('2411.12806v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.12806v2-abstract-full" style="display: none;"> We construct a new family of quantum chaotic models by combining multiple copies of integrable commuting SYK models. As each copy of the commuting SYK model does not commute with others, this construction breaks the integrability of each commuting SYK and the family of models demonstrates the emergence of quantum chaos. We study the spectrum of this model analytically in the double-scaled limit. As the number of copies tends to infinity, the spectrum becomes compact and equivalent to the regular SYK model. For finite $d$ copies, the spectrum is close to the regular SYK model in UV but has an exponential tail $e^{E/T_c}$ in the IR. We identify the reciprocal of the exponent in the tail as a critical temperature $T_c$, above which the model should be quantum chaotic. $T_c$ monotonically decreases as $d$ increases, which expands the chaotic regime over the non-chaotic regime. We propose the existence of a new phase around $T_c$, and the dynamics should be very different in two phases. We further carry out numeric analysis at finite $d$, which supports our proposal. Given any finite dimensional local Hamiltonian, by decomposing it into $d$ groups, in which all terms in one group commute with each other but terms from different groups may not, our analysis can give an estimate of the critical temperature for quantum chaos based on the decomposition. We also comment on the implication of the critical temperature to future quantum simulations of quantum chaos and quantum gravity. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.12806v2-abstract-full').style.display = 'none'; document.getElementById('2411.12806v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 9 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 19 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">26 pages plus appendix, 16 figures, 2 tables</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.10994">arXiv:2408.10994</a> <span> [<a href="https://arxiv.org/pdf/2408.10994">pdf</a>, <a href="https://arxiv.org/format/2408.10994">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Microsatellite-based real-time quantum key distribution </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Cai%2C+W">Wen-Qi Cai</a>, <a href="/search/quant-ph?searchtype=author&query=Ren%2C+J">Ji-Gang Ren</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+C">Chao-Ze Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+M">Meng Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+L">Liang Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+H">Hui-Ying Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Chang%2C+L">Liang Chang</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+J">Jin-Cai Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Jin%2C+B">Biao Jin</a>, <a href="/search/quant-ph?searchtype=author&query=Xue%2C+H">Hua-Jian Xue</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xue-Jiao Li</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+H">Hui Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Yu%2C+G">Guang-Wen Yu</a>, <a href="/search/quant-ph?searchtype=author&query=Tao%2C+X">Xue-Ying Tao</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+T">Ting Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+C">Chong-Fei Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Luo%2C+W">Wen-Bin Luo</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+J">Jie Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Yong%2C+H">Hai-Lin Yong</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yu-Huai Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+F">Feng-Zhi Li</a>, <a href="/search/quant-ph?searchtype=author&query=Jiang%2C+C">Cong Jiang</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+H">Hao-Ze Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+C">Chao Wu</a> , et al. (16 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2408.10994v1-abstract-short" style="display: inline;"> A quantum network provides an infrastructure connecting quantum devices with revolutionary computing, sensing, and communication capabilities. As the best-known application of a quantum network, quantum key distribution (QKD) shares secure keys guaranteed by the laws of quantum mechanics. A quantum satellite constellation offers a solution to facilitate the quantum network on a global scale. The M… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.10994v1-abstract-full').style.display = 'inline'; document.getElementById('2408.10994v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.10994v1-abstract-full" style="display: none;"> A quantum network provides an infrastructure connecting quantum devices with revolutionary computing, sensing, and communication capabilities. As the best-known application of a quantum network, quantum key distribution (QKD) shares secure keys guaranteed by the laws of quantum mechanics. A quantum satellite constellation offers a solution to facilitate the quantum network on a global scale. The Micius satellite has verified the feasibility of satellite quantum communications, however, scaling up quantum satellite constellations is challenging, requiring small lightweight satellites, portable ground stations and real-time secure key exchange. Here we tackle these challenges and report the development of a quantum microsatellite capable of performing space-to-ground QKD using portable ground stations. The quantum microsatellite features a payload weighing approximately 23 kg, while the portable ground station weighs about 100 kg. These weights represent reductions by more than an order and two orders of magnitude, respectively, compared to the Micius satellite. Additionally, we multiplex bidirectional satellite-ground optical communication with quantum communication, enabling key distillation and secure communication in real-time. Using the microsatellite and the portable ground stations, we demonstrate satellite-based QKD with multiple ground stations and achieve the sharing of up to 0.59 million bits of secure keys during a single satellite pass. The compact quantum payload can be readily assembled on existing space stations or small satellites, paving the way for a satellite-constellation-based quantum and classical network for widespread real-life applications. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.10994v1-abstract-full').style.display = 'none'; document.getElementById('2408.10994v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 20 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">40 pages, 8 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.04361">arXiv:2408.04361</a> <span> [<a href="https://arxiv.org/pdf/2408.04361">pdf</a>, <a href="https://arxiv.org/format/2408.04361">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Ultrabright-entanglement-based quantum key distribution over a 404-km-long optical fiber </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhuang%2C+S">Shi-Chang Zhuang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+B">Bo Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zheng%2C+M">Ming-Yang Zheng</a>, <a href="/search/quant-ph?searchtype=author&query=Zeng%2C+Y">Yi-Xi Zeng</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+H">Hui-Nan Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+G">Guang-Bing Li</a>, <a href="/search/quant-ph?searchtype=author&query=Yao%2C+Q">Quan Yao</a>, <a href="/search/quant-ph?searchtype=author&query=Xie%2C+X">Xiu-Ping Xie</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yu-Huai Li</a>, <a href="/search/quant-ph?searchtype=author&query=Qin%2C+H">Hao Qin</a>, <a href="/search/quant-ph?searchtype=author&query=You%2C+L">Li-Xing You</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+F">Fei-Hu Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Yin%2C+J">Juan Yin</a>, <a href="/search/quant-ph?searchtype=author&query=Cao%2C+Y">Yuan Cao</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Q">Qiang Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Cheng-Zhi Peng</a>, <a href="/search/quant-ph?searchtype=author&query=Pan%2C+J">Jian-Wei Pan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2408.04361v2-abstract-short" style="display: inline;"> The entangled photons are crucial resources for quantum communications and networking. Here, we present an ultra-bright polarization-entangled photon source based on a periodically poled lithium niobate waveguide designed for practical quantum communication networks. Using a 780 nm pump laser, the source achieves a pair generation rate of 2.4 $\times 10^{10}$ pairs/s/mW. This work has achieved a d… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.04361v2-abstract-full').style.display = 'inline'; document.getElementById('2408.04361v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.04361v2-abstract-full" style="display: none;"> The entangled photons are crucial resources for quantum communications and networking. Here, we present an ultra-bright polarization-entangled photon source based on a periodically poled lithium niobate waveguide designed for practical quantum communication networks. Using a 780 nm pump laser, the source achieves a pair generation rate of 2.4 $\times 10^{10}$ pairs/s/mW. This work has achieved a directly measured power of 17.9 nW in entangled photon generation with a 3.2 mW pump power. Based on this, we demonstrate the practicality of the source by conducting quantum key distribution experiments over long-distance fiber links, achieving the applicable secure key rates of up to 440.80 bits/s over 200 km with 62 dB loss and reaching a maximum secure key generation distance of 404 km. These results demonstrate the potential of wavelength-multiplexed polarization-entangled photon sources for high-speed, long-distance quantum communication, positioning them as key components for future large-scale quantum networks. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.04361v2-abstract-full').style.display = 'none'; document.getElementById('2408.04361v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 8 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 8 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">18 pages, 6 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.03259">arXiv:2408.03259</a> <span> [<a href="https://arxiv.org/pdf/2408.03259">pdf</a>, <a href="https://arxiv.org/format/2408.03259">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.133.020201">10.1103/PhysRevLett.133.020201 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Single-photon interference over 8.4 km urban atmosphere: towards testing quantum effects in curved spacetime with photons </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wu%2C+H">Hui-Nan Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yu-Huai Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+B">Bo Li</a>, <a href="/search/quant-ph?searchtype=author&query=You%2C+X">Xiang You</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+R">Run-Ze Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Ren%2C+J">Ji-Gang Ren</a>, <a href="/search/quant-ph?searchtype=author&query=Yin%2C+J">Juan Yin</a>, <a href="/search/quant-ph?searchtype=author&query=Lu%2C+C">Chao-Yang Lu</a>, <a href="/search/quant-ph?searchtype=author&query=Cao%2C+Y">Yuan Cao</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Cheng-Zhi Peng</a>, <a href="/search/quant-ph?searchtype=author&query=Pan%2C+J">Jian-Wei Pan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2408.03259v2-abstract-short" style="display: inline;"> The emergence of quantum mechanics and general relativity has transformed our understanding of the natural world significantly. However, integrating these two theories presents immense challenges, and their interplay remains untested. Recent theoretical studies suggest that the single-photon interference covering huge space can effectively probe the interface between quantum mechanics and general… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.03259v2-abstract-full').style.display = 'inline'; document.getElementById('2408.03259v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.03259v2-abstract-full" style="display: none;"> The emergence of quantum mechanics and general relativity has transformed our understanding of the natural world significantly. However, integrating these two theories presents immense challenges, and their interplay remains untested. Recent theoretical studies suggest that the single-photon interference covering huge space can effectively probe the interface between quantum mechanics and general relativity. We developed an alternative design using unbalanced Michelson interferometers to address this and validated its feasibility over an 8.4 km free-space channel. Using a high-brightness single-photon source based on quantum dots, we demonstrated single-photon interference along this long-distance baseline. We achieved a phase measurement precision of 16.2 mrad, which satisfied the measurement requirements for a gravitational redshift at the geosynchronous orbit by five times the standard deviation. Our results confirm the feasibility of the single-photon version of the Colella-Overhauser-Werner experiment for testing the quantum effects in curved spacetime. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.03259v2-abstract-full').style.display = 'none'; document.getElementById('2408.03259v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 6 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">22 pages, 6 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 133, 020201 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.00276">arXiv:2408.00276</a> <span> [<a href="https://arxiv.org/pdf/2408.00276">pdf</a>, <a href="https://arxiv.org/format/2408.00276">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Computational Physics">physics.comp-ph</span> </div> </div> <p class="title is-5 mathjax"> Provably Efficient Adiabatic Learning for Quantum-Classical Dynamics </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Changnan Peng</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+J">Jin-Peng Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Chern%2C+G">Gia-Wei Chern</a>, <a href="/search/quant-ph?searchtype=author&query=Luo%2C+D">Di Luo</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2408.00276v2-abstract-short" style="display: inline;"> Quantum-classical hybrid dynamics is crucial for accurately simulating complex systems where both quantum and classical behaviors need to be considered. However, coupling between classical and quantum degrees of freedom and the exponential growth of the Hilbert space present significant challenges. Current machine learning approaches for predicting such dynamics, while promising, remain unknown in… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.00276v2-abstract-full').style.display = 'inline'; document.getElementById('2408.00276v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.00276v2-abstract-full" style="display: none;"> Quantum-classical hybrid dynamics is crucial for accurately simulating complex systems where both quantum and classical behaviors need to be considered. However, coupling between classical and quantum degrees of freedom and the exponential growth of the Hilbert space present significant challenges. Current machine learning approaches for predicting such dynamics, while promising, remain unknown in their error bounds, sample complexity, and generalizability. In this work, we establish a generic theoretical framework for analyzing quantum-classical adiabatic dynamics with learning algorithms. Based on quantum information theory, we develop a provably efficient adiabatic learning (PEAL) algorithm with logarithmic system size sampling complexity and favorable time scaling properties. We benchmark PEAL on the Holstein model, and demonstrate its accuracy in predicting single-path dynamics and ensemble dynamics observables as well as transfer learning over a family of Hamiltonians. Our framework and algorithm open up new avenues for reliable and efficient learning of quantum-classical dynamics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.00276v2-abstract-full').style.display = 'none'; document.getElementById('2408.00276v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 8 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 1 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.21415">arXiv:2407.21415</a> <span> [<a href="https://arxiv.org/pdf/2407.21415">pdf</a>, <a href="https://arxiv.org/format/2407.21415">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> In situ Qubit Frequency Tuning Circuit for Scalable Superconducting Quantum Computing: Scheme and Experiment </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Jiang%2C+L">Lei Jiang</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+Y">Yu Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shaowei Li</a>, <a href="/search/quant-ph?searchtype=author&query=Yan%2C+Z">Zhiguang Yan</a>, <a href="/search/quant-ph?searchtype=author&query=Gong%2C+M">Ming Gong</a>, <a href="/search/quant-ph?searchtype=author&query=Rong%2C+T">Tao Rong</a>, <a href="/search/quant-ph?searchtype=author&query=Sun%2C+C">Chenyin Sun</a>, <a href="/search/quant-ph?searchtype=author&query=Sun%2C+T">Tianzuo Sun</a>, <a href="/search/quant-ph?searchtype=author&query=Jiang%2C+T">Tao Jiang</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+H">Hui Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Zha%2C+C">Chen Zha</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+J">Jin Lin</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+F">Fusheng Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+Q">Qingling Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Ye%2C+Y">Yangsen Ye</a>, <a href="/search/quant-ph?searchtype=author&query=Rong%2C+H">Hao Rong</a>, <a href="/search/quant-ph?searchtype=author&query=Yan%2C+K">Kai Yan</a>, <a href="/search/quant-ph?searchtype=author&query=Cao%2C+S">Sirui Cao</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yuan Li</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+S">Shaojun Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Qian%2C+H">Haoran Qian</a>, <a href="/search/quant-ph?searchtype=author&query=Hu%2C+Y">Yisen Hu</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yulin Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yuhuai Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+G">Gang Wu</a> , et al. (8 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2407.21415v2-abstract-short" style="display: inline;"> Frequency tunable qubit plays a significant role for scalable superconducting quantum processors. The state-of-the-art room-temperature electronics for tuning qubit frequency suffers from unscalable limit, such as heating problem, linear growth of control cables, etc. Here we propose a scalable scheme to tune the qubit frequency by using in situ superconducting circuit, which is based on radio fre… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.21415v2-abstract-full').style.display = 'inline'; document.getElementById('2407.21415v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.21415v2-abstract-full" style="display: none;"> Frequency tunable qubit plays a significant role for scalable superconducting quantum processors. The state-of-the-art room-temperature electronics for tuning qubit frequency suffers from unscalable limit, such as heating problem, linear growth of control cables, etc. Here we propose a scalable scheme to tune the qubit frequency by using in situ superconducting circuit, which is based on radio frequency superconducting quantum interference device (rf-SQUID). We demonstrate both theoretically and experimentally that the qubit frequency could be modulated by inputting several single pulses into rf-SQUID. Compared with the traditional scheme, our scheme not only solves the heating problem, but also provides the potential to exponentially reduce the number of cables inside the dilute refrigerator and the room-temperature electronics resource for tuning qubit frequency, which is achieved by a time-division-multiplex (TDM) scheme combining rf-SQUID with switch arrays. With such TDM scheme, the number of cables could be reduced from the usual $\sim 3n$ to $\sim \log_2{(3n)} + 1$ for two-dimensional quantum processors comprising $n$ qubits and $\sim 2n$ couplers. Our work paves the way for large-scale control of superconducting quantum processor. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.21415v2-abstract-full').style.display = 'none'; document.getElementById('2407.21415v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 31 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">9 pages, 6 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.20225">arXiv:2407.20225</a> <span> [<a href="https://arxiv.org/pdf/2407.20225">pdf</a>, <a href="https://arxiv.org/format/2407.20225">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Theory">hep-th</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Lattice">hep-lat</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Hamiltonian Lattice Formulation of Compact Maxwell-Chern-Simons Theory </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Changnan Peng</a>, <a href="/search/quant-ph?searchtype=author&query=Diamantini%2C+M+C">Maria Cristina Diamantini</a>, <a href="/search/quant-ph?searchtype=author&query=Funcke%2C+L">Lena Funcke</a>, <a href="/search/quant-ph?searchtype=author&query=Hassan%2C+S+M+A">Syed Muhammad Ali Hassan</a>, <a href="/search/quant-ph?searchtype=author&query=Jansen%2C+K">Karl Jansen</a>, <a href="/search/quant-ph?searchtype=author&query=K%C3%BChn%2C+S">Stefan K眉hn</a>, <a href="/search/quant-ph?searchtype=author&query=Luo%2C+D">Di Luo</a>, <a href="/search/quant-ph?searchtype=author&query=Naredi%2C+P">Pranay Naredi</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2407.20225v2-abstract-short" style="display: inline;"> In this paper, a Hamiltonian lattice formulation for 2+1D compact Maxwell-Chern-Simons theory is derived. We analytically solve this theory and demonstrate that the mass gap in the continuum limit matches the well-known continuum formula. Our formulation preserves topological features such as the quantization of the Chern-Simons level, the degeneracy of energy eigenstates, the non-trivial properti… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.20225v2-abstract-full').style.display = 'inline'; document.getElementById('2407.20225v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.20225v2-abstract-full" style="display: none;"> In this paper, a Hamiltonian lattice formulation for 2+1D compact Maxwell-Chern-Simons theory is derived. We analytically solve this theory and demonstrate that the mass gap in the continuum limit matches the well-known continuum formula. Our formulation preserves topological features such as the quantization of the Chern-Simons level, the degeneracy of energy eigenstates, the non-trivial properties of Wilson loops, and the mutual and self statistics of anyons. This work lays the groundwork for future Hamiltonian-based simulations of Maxwell-Chern-Simons theory on classical and quantum computers. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.20225v2-abstract-full').style.display = 'none'; document.getElementById('2407.20225v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 29 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2406.02045">arXiv:2406.02045</a> <span> [<a href="https://arxiv.org/pdf/2406.02045">pdf</a>, <a href="https://arxiv.org/format/2406.02045">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Experimental single-photon quantum key distribution surpassing the fundamental coherent-state rate limit </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Y">Yang Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Ding%2C+X">Xing Ding</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+L">Likang Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Y">Yong-Peng Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+G">Gao-Qiang Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Ning%2C+Z">Zhen Ning</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+M">Mo-Chi Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+R">Run-Ze Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+J">Jun-Yi Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Zou%2C+G">Geng-Yan Zou</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+H">Hui Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Cao%2C+Y">Yuan Cao</a>, <a href="/search/quant-ph?searchtype=author&query=He%2C+Y">Yu-Ming He</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Cheng-Zhi Peng</a>, <a href="/search/quant-ph?searchtype=author&query=Huo%2C+Y">Yong-Heng Huo</a>, <a href="/search/quant-ph?searchtype=author&query=Liao%2C+S">Sheng-Kai Liao</a>, <a href="/search/quant-ph?searchtype=author&query=Lu%2C+C">Chao-Yang Lu</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+F">Feihu Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Pan%2C+J">Jian-Wei Pan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2406.02045v1-abstract-short" style="display: inline;"> Single-photon sources are essential for quantum networks, enabling applications ranging from quantum key distribution (QKD) to the burgeoning quantum internet. Despite the remarkable advancements, the current reliance of QKD on attenuated coherent (laser) light sources has imposed a fundamental limit on the secret key rate (SKR). This constraint is primarily attributable to the scarcity of single-… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.02045v1-abstract-full').style.display = 'inline'; document.getElementById('2406.02045v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2406.02045v1-abstract-full" style="display: none;"> Single-photon sources are essential for quantum networks, enabling applications ranging from quantum key distribution (QKD) to the burgeoning quantum internet. Despite the remarkable advancements, the current reliance of QKD on attenuated coherent (laser) light sources has imposed a fundamental limit on the secret key rate (SKR). This constraint is primarily attributable to the scarcity of single-photon components within coherent light, confined by an inherent upper bound of 1/e. Here, we report high-rate QKD using a high-efficiency single-photon source, enabling an SKR transcending the fundamental rate limit of coherent light. We developed an on-demand, bright semiconductor quantum-dot single-photon source with an efficiency of 0.71(2), exceeding the inherent bound of coherent light by approximately 2.87 dB. Implementing narrow-bandwidth filtering and random polarization modulation, we conducted a field QKD trial over a 14.6(1.1)-dB-loss free-space urban channel, achieving an SKR of 0.00108 bits per pulse. This surpasses the practical limit of coherent-light-based QKD by 2.53 dB. Our findings conclusively demonstrate the superior performance of nanotechnology-based single-photon sources over coherent light for QKD applications, marking a pivotal stride towards the realization of a global quantum internet. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.02045v1-abstract-full').style.display = 'none'; document.getElementById('2406.02045v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 June, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">22 pages, 5 figures, 1 Table</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2401.17022">arXiv:2401.17022</a> <span> [<a href="https://arxiv.org/pdf/2401.17022">pdf</a>, <a href="https://arxiv.org/format/2401.17022">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1126/science.ado3912">10.1126/science.ado3912 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Realization of fractional quantum Hall state with interacting photons </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wang%2C+C">Can Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+F">Feng-Ming Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+M">Ming-Cheng Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+H">He Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+X">Xian-He Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Ying%2C+C">Chong Ying</a>, <a href="/search/quant-ph?searchtype=author&query=Shang%2C+Z">Zhong-Xia Shang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+J">Jian-Wen Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Huo%2C+Y">Yong-Heng Huo</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Cheng-Zhi Peng</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+X">Xiaobo Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Lu%2C+C">Chao-Yang Lu</a>, <a href="/search/quant-ph?searchtype=author&query=Pan%2C+J">Jian-Wei Pan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2401.17022v1-abstract-short" style="display: inline;"> Fractional quantum Hall (FQH) states, known for their robust topological order and the emergence of non-Abelian anyons, have captured significant interest due to the appealing applications in fault-tolerant quantum computing. Bottom-up approach on an engineered quantum platform will provide opportunities to operate FQH states without external magnetic field and enhance local and coherent manipulat… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.17022v1-abstract-full').style.display = 'inline'; document.getElementById('2401.17022v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2401.17022v1-abstract-full" style="display: none;"> Fractional quantum Hall (FQH) states, known for their robust topological order and the emergence of non-Abelian anyons, have captured significant interest due to the appealing applications in fault-tolerant quantum computing. Bottom-up approach on an engineered quantum platform will provide opportunities to operate FQH states without external magnetic field and enhance local and coherent manipulation of these exotic states. Here we demonstrate a lattice version of photon FQH state using a programmable on-chip platform based on photon blockade and engineering gauge fields on a novel two-dimensional circuit quantum electrodynamics (QED) system. We first observe the effective photon Lorentz force and butterfly spectrum in the artificial gauge field, a prerequisite for FQH states. After adiabatic assembly of Laughlin FQH wavefunction of 1/2 filling factor from localized photons, we observe strong density correlation and chiral topological flow among the FQH photons. We then verify the unique features of FQH states in response to external fields, including the incompressibility of generating quasiparticles and the smoking-gun signature of fractional quantum Hall conductivity. Our work represents a significant advance in the bottom-up creation and manipulation of novel strongly correlated topological quantum matter composed of photons and opens up possibilities for fault-tolerant quantum information devices. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.17022v1-abstract-full').style.display = 'none'; document.getElementById('2401.17022v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 January, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 pages, 6 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Science 384, 579-584 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2307.02364">arXiv:2307.02364</a> <span> [<a href="https://arxiv.org/pdf/2307.02364">pdf</a>, <a href="https://arxiv.org/format/2307.02364">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41566-023-01166-4">10.1038/s41566-023-01166-4 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> High-rate quantum key distribution exceeding 110 Mb/s </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+W">Wei Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+L">Likang Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Tan%2C+H">Hao Tan</a>, <a href="/search/quant-ph?searchtype=author&query=Lu%2C+Y">Yichen Lu</a>, <a href="/search/quant-ph?searchtype=author&query=Liao%2C+S">Sheng-Kai Liao</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+J">Jia Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+H">Hao Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zhen Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Mao%2C+H">Hao-Kun Mao</a>, <a href="/search/quant-ph?searchtype=author&query=Yan%2C+B">Bingze Yan</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Q">Qiong Li</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+Y">Yang Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Q">Qiang Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Cheng-Zhi Peng</a>, <a href="/search/quant-ph?searchtype=author&query=You%2C+L">Lixing You</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+F">Feihu Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Pan%2C+J">Jian-Wei Pan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2307.02364v1-abstract-short" style="display: inline;"> Quantum key distribution (QKD) can provide fundamentally proven security for secure communication. Toward application, the secret key rate (SKR) is a key figure of merit for any QKD system. So far, the SKR has been limited to about a few megabit-per-second. Here we report a QKD system that is able to generate key at a record high SKR of 115.8 Mb/s over 10-km standard fibre, and to distribute key o… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2307.02364v1-abstract-full').style.display = 'inline'; document.getElementById('2307.02364v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2307.02364v1-abstract-full" style="display: none;"> Quantum key distribution (QKD) can provide fundamentally proven security for secure communication. Toward application, the secret key rate (SKR) is a key figure of merit for any QKD system. So far, the SKR has been limited to about a few megabit-per-second. Here we report a QKD system that is able to generate key at a record high SKR of 115.8 Mb/s over 10-km standard fibre, and to distribute key over up to 328 km of ultra-low-loss fibre. This attributes to a multi-pixel superconducting nanowire single-photon detector with ultrahigh counting rate, an integrated transmitter that can stably encode polarization states with low error, a fast post-processing algorithm for generating key in real time and the high system clock-rate operation. The results demonstrate the feasibility of practical high-rate QKD with photonic techniques, thus opening its possibility for widespread applications. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2307.02364v1-abstract-full').style.display = 'none'; document.getElementById('2307.02364v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 July, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Photonics 17, 416-421 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2306.17428">arXiv:2306.17428</a> <span> [<a href="https://arxiv.org/pdf/2306.17428">pdf</a>, <a href="https://arxiv.org/format/2306.17428">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevApplied.19.064083">10.1103/PhysRevApplied.19.064083 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Pure-state photon-pair source with a long coherence time for large-scale quantum information processing </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+B">Bo Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yu-Huai Li</a>, <a href="/search/quant-ph?searchtype=author&query=Cao%2C+Y">Yuan Cao</a>, <a href="/search/quant-ph?searchtype=author&query=Yin%2C+J">Juan Yin</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Cheng-Zhi Peng</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2306.17428v1-abstract-short" style="display: inline;"> The Hong-Ou-Mandel interference between independent photons plays a pivotal role in the large-scale quantum networks involving distant nodes. Photons need to work in a pure state for indistinguishability to reach high-quality interference. Also, they need to have a sufficiently long coherence time to reduce the time synchronization requirements in practical application. In this paper, we discuss a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.17428v1-abstract-full').style.display = 'inline'; document.getElementById('2306.17428v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2306.17428v1-abstract-full" style="display: none;"> The Hong-Ou-Mandel interference between independent photons plays a pivotal role in the large-scale quantum networks involving distant nodes. Photons need to work in a pure state for indistinguishability to reach high-quality interference. Also, they need to have a sufficiently long coherence time to reduce the time synchronization requirements in practical application. In this paper, we discuss a scheme for generating a pure-state photon-pair source with a long coherence time in periodically poled potassium titanyl phosphate (PPKTP) crystals. By selecting the appropriate pump laser and filter, we could simultaneously eliminate the frequency correlation of the parametric photons while achieving a long coherence time. We experimentally developed this pure-state photon-pair source of 780 nm on PPKTP crystals pumped by a 390 nm pulsed laser. The source provided a coherence time of tens of picoseconds, and it showed to have the potential to be applied in long-distance quantum interference. Furthermore, we experimentally demonstrated the Hong-Ou-Mandel (HOM) interference between two photon sources with visibility exceeding the classical limit. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.17428v1-abstract-full').style.display = 'none'; document.getElementById('2306.17428v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 June, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Applied 19, 064083 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2305.15972">arXiv:2305.15972</a> <span> [<a href="https://arxiv.org/pdf/2305.15972">pdf</a>, <a href="https://arxiv.org/format/2305.15972">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Logical Magic State Preparation with Fidelity Beyond the Distillation Threshold on a Superconducting Quantum Processor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Ye%2C+Y">Yangsen Ye</a>, <a href="/search/quant-ph?searchtype=author&query=He%2C+T">Tan He</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+H">He-Liang Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Wei%2C+Z">Zuolin Wei</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Y">Yiming Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+Y">Youwei Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+D">Dachao Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+Q">Qingling Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Guan%2C+H">Huijie Guan</a>, <a href="/search/quant-ph?searchtype=author&query=Cao%2C+S">Sirui Cao</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+F">Fusheng Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chung%2C+T">Tung-Hsun Chung</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+H">Hui Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Fan%2C+D">Daojin Fan</a>, <a href="/search/quant-ph?searchtype=author&query=Gong%2C+M">Ming Gong</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+C">Cheng Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+S">Shaojun Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Han%2C+L">Lianchen Han</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+N">Na Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shaowei Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yuan Li</a>, <a href="/search/quant-ph?searchtype=author&query=Liang%2C+F">Futian Liang</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+J">Jin Lin</a>, <a href="/search/quant-ph?searchtype=author&query=Qian%2C+H">Haoran Qian</a>, <a href="/search/quant-ph?searchtype=author&query=Rong%2C+H">Hao Rong</a> , et al. (13 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2305.15972v2-abstract-short" style="display: inline;"> Fault-tolerant quantum computing based on surface code has emerged as an attractive candidate for practical large-scale quantum computers to achieve robust noise resistance. To achieve universality, magic states preparation is a commonly approach for introducing non-Clifford gates. Here, we present a hardware-efficient and scalable protocol for arbitrary logical state preparation for the rotated s… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.15972v2-abstract-full').style.display = 'inline'; document.getElementById('2305.15972v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2305.15972v2-abstract-full" style="display: none;"> Fault-tolerant quantum computing based on surface code has emerged as an attractive candidate for practical large-scale quantum computers to achieve robust noise resistance. To achieve universality, magic states preparation is a commonly approach for introducing non-Clifford gates. Here, we present a hardware-efficient and scalable protocol for arbitrary logical state preparation for the rotated surface code, and further experimentally implement it on the \textit{Zuchongzhi} 2.1 superconducting quantum processor. An average of \hhl{$0.8983 \pm 0.0002$} logical fidelity at different logical states with distance-three is achieved, \hhl{taking into account both state preparation and measurement errors.} In particular, \hhl{the magic states $|A^{蟺/4}\rangle_L$, $|H\rangle_L$, and $|T\rangle_L$ are prepared non-destructively with logical fidelities of $0.8771 \pm 0.0009 $, $0.9090 \pm 0.0009 $, and $0.8890 \pm 0.0010$, respectively, which are higher than the state distillation protocol threshold, 0.859 (for H-type magic state) and 0.827 (for T -type magic state).} Our work provides a viable and efficient avenue for generating high-fidelity raw logical magic states, which is essential for realizing non-Clifford logical gates in the surface code. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.15972v2-abstract-full').style.display = 'none'; document.getElementById('2305.15972v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 May, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 25 May, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">In this version, we do not employ readout error mitigation strategies (in the previous version, we use readout transition matrix to mitigate the measurement error) to remove measurement errors because we believe it provides a more predictive assessment of the actual fidelity when generating and consuming magic states for a non-Clifford gate, as consuming the state involves measurement</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2305.07787">arXiv:2305.07787</a> <span> [<a href="https://arxiv.org/pdf/2305.07787">pdf</a>, <a href="https://arxiv.org/format/2305.07787">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Other Condensed Matter">cond-mat.other</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> On Ultrafast X-ray Methods for Magnetism </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Plumley%2C+R">Rajan Plumley</a>, <a href="/search/quant-ph?searchtype=author&query=Chitturi%2C+S">Sathya Chitturi</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Cheng Peng</a>, <a href="/search/quant-ph?searchtype=author&query=Assefa%2C+T">Tadesse Assefa</a>, <a href="/search/quant-ph?searchtype=author&query=Burdet%2C+N">Nicholas Burdet</a>, <a href="/search/quant-ph?searchtype=author&query=Shen%2C+L">Lingjia Shen</a>, <a href="/search/quant-ph?searchtype=author&query=Reid%2C+A">Alex Reid</a>, <a href="/search/quant-ph?searchtype=author&query=Dakovski%2C+G">Georgi Dakovski</a>, <a href="/search/quant-ph?searchtype=author&query=Seaberg%2C+M">Matthew Seaberg</a>, <a href="/search/quant-ph?searchtype=author&query=O%27Dowd%2C+F">Frank O'Dowd</a>, <a href="/search/quant-ph?searchtype=author&query=Montoya%2C+S">Sergio Montoya</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+H">Hongwei Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Okullo%2C+A">Alana Okullo</a>, <a href="/search/quant-ph?searchtype=author&query=Mardanya%2C+S">Sougata Mardanya</a>, <a href="/search/quant-ph?searchtype=author&query=Kevan%2C+S">Stephen Kevan</a>, <a href="/search/quant-ph?searchtype=author&query=Fischer%2C+P">Peter Fischer</a>, <a href="/search/quant-ph?searchtype=author&query=Fullerton%2C+E">Eric Fullerton</a>, <a href="/search/quant-ph?searchtype=author&query=Sinha%2C+S">Sunil Sinha</a>, <a href="/search/quant-ph?searchtype=author&query=Colocho%2C+W">William Colocho</a>, <a href="/search/quant-ph?searchtype=author&query=Lutman%2C+A">Alberto Lutman</a>, <a href="/search/quant-ph?searchtype=author&query=Decker%2C+F">Franz-Joseph Decker</a>, <a href="/search/quant-ph?searchtype=author&query=Roy%2C+S">Sujoy Roy</a>, <a href="/search/quant-ph?searchtype=author&query=Fujioka%2C+J">Jun Fujioka</a>, <a href="/search/quant-ph?searchtype=author&query=Tokura%2C+Y">Yoshinori Tokura</a>, <a href="/search/quant-ph?searchtype=author&query=Minitti%2C+M+P">Michael P. Minitti</a> , et al. (14 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2305.07787v1-abstract-short" style="display: inline;"> With the introduction of x-ray free electron laser sources around the world, new scientific approaches for visualizing matter at fundamental length and time-scales have become possible. As it relates to magnetism and "magnetic-type" systems, advanced methods are being developed for studying ultrafast magnetic responses on the time-scales at which they occur. We describe three capabilities which ha… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.07787v1-abstract-full').style.display = 'inline'; document.getElementById('2305.07787v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2305.07787v1-abstract-full" style="display: none;"> With the introduction of x-ray free electron laser sources around the world, new scientific approaches for visualizing matter at fundamental length and time-scales have become possible. As it relates to magnetism and "magnetic-type" systems, advanced methods are being developed for studying ultrafast magnetic responses on the time-scales at which they occur. We describe three capabilities which have the potential to seed new directions in this area and present original results from each: pump-probe x-ray scattering with low energy excitation, x-ray photon fluctuation spectroscopy, and ultrafast diffuse x-ray scattering. By combining these experimental techniques with advanced modeling together with machine learning, we describe how the combination of these domains allows for a new understanding in the field of magnetism. Finally, we give an outlook for future areas of investigation and the newly developed instruments which will take us there. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.07787v1-abstract-full').style.display = 'none'; document.getElementById('2305.07787v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 May, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2023. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2303.14683">arXiv:2303.14683</a> <span> [<a href="https://arxiv.org/pdf/2303.14683">pdf</a>, <a href="https://arxiv.org/format/2303.14683">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevApplied.20.044013">10.1103/PhysRevApplied.20.044013 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Effect of light injection on the security of practical quantum key distribution </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Han%2C+L">Liying Han</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Tan%2C+H">Hao Tan</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+W">Weiyang Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Cai%2C+W">Wenqi Cai</a>, <a href="/search/quant-ph?searchtype=author&query=Yin%2C+J">Juan Yin</a>, <a href="/search/quant-ph?searchtype=author&query=Ren%2C+J">Jigang Ren</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+F">Feihu Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Liao%2C+S">Shengkai Liao</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Chengzhi Peng</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2303.14683v2-abstract-short" style="display: inline;"> Quantum key distribution (QKD) based on the fundamental laws of quantum physics can allow the distribution of secure keys between distant users. However, the imperfections in realistic devices may lead to potential security risks, which must be accurately characterized and considered in practical security analysis. High-speed optical modulators, being as one of the core components of practical QKD… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.14683v2-abstract-full').style.display = 'inline'; document.getElementById('2303.14683v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2303.14683v2-abstract-full" style="display: none;"> Quantum key distribution (QKD) based on the fundamental laws of quantum physics can allow the distribution of secure keys between distant users. However, the imperfections in realistic devices may lead to potential security risks, which must be accurately characterized and considered in practical security analysis. High-speed optical modulators, being as one of the core components of practical QKD systems, can be used to prepare the required quantum states. Here, we find that optical modulators based on LiNbO3, including phase modulators and intensity modulators, are vulnerable to photorefractive effect caused by external light injection. By changing the power of external light, eavesdroppers can control the intensities of the prepared states, posing a potential threat to the security of QKD. We have experimentally demonstrated the influence of light injection on LiNbO3-based optical modulators and analyzed the security risks caused by the potential green light injection attack, along with the corresponding countermeasures. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.14683v2-abstract-full').style.display = 'none'; document.getElementById('2303.14683v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 2 January, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 26 March, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2023. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2212.08006">arXiv:2212.08006</a> <span> [<a href="https://arxiv.org/pdf/2212.08006">pdf</a>, <a href="https://arxiv.org/format/2212.08006">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41567-024-02530-z">10.1038/s41567-024-02530-z <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Experimental quantum computational chemistry with optimised unitary coupled cluster ansatz </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Guo%2C+S">Shaojun Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Sun%2C+J">Jinzhao Sun</a>, <a href="/search/quant-ph?searchtype=author&query=Qian%2C+H">Haoran Qian</a>, <a href="/search/quant-ph?searchtype=author&query=Gong%2C+M">Ming Gong</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Y">Yukun Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+F">Fusheng Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Ye%2C+Y">Yangsen Ye</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yulin Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Cao%2C+S">Sirui Cao</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+K">Kun Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Zha%2C+C">Chen Zha</a>, <a href="/search/quant-ph?searchtype=author&query=Ying%2C+C">Chong Ying</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+Q">Qingling Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+H">He-Liang Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+Y">Youwei Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shaowei Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+S">Shiyu Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Yu%2C+J">Jiale Yu</a>, <a href="/search/quant-ph?searchtype=author&query=Fan%2C+D">Daojin Fan</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+D">Dachao Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Su%2C+H">Hong Su</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+H">Hui Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Rong%2C+H">Hao Rong</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yuan Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kaili Zhang</a> , et al. (13 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2212.08006v3-abstract-short" style="display: inline;"> Quantum computational chemistry has emerged as an important application of quantum computing. Hybrid quantum-classical computing methods, such as variational quantum eigensolvers (VQE), have been designed as promising solutions to quantum chemistry problems, yet challenges due to theoretical complexity and experimental imperfections hinder progress in achieving reliable and accurate results. Exper… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2212.08006v3-abstract-full').style.display = 'inline'; document.getElementById('2212.08006v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2212.08006v3-abstract-full" style="display: none;"> Quantum computational chemistry has emerged as an important application of quantum computing. Hybrid quantum-classical computing methods, such as variational quantum eigensolvers (VQE), have been designed as promising solutions to quantum chemistry problems, yet challenges due to theoretical complexity and experimental imperfections hinder progress in achieving reliable and accurate results. Experimental works for solving electronic structures are consequently still restricted to nonscalable (hardware efficient) or classically simulable (Hartree-Fock) ansatz, or limited to a few qubits with large errors. The experimental realisation of scalable and high-precision quantum chemistry simulation remains elusive. Here, we address the critical challenges {associated with} solving molecular electronic structures using noisy quantum processors. Our protocol presents significant improvements in the circuit depth and running time, key metrics for chemistry simulation. Through systematic hardware enhancements and the integration of error mitigation techniques, we push forward the limit of experimental quantum computational chemistry and successfully scale up the implementation of VQE with an optimised unitary coupled-cluster ansatz to 12 qubits. We produce high-precision results of the ground-state energy for molecules with error suppression by around two orders of magnitude. We achieve chemical accuracy for H$_2$ at all bond distances and LiH at small bond distances in the experiment, even beyond the two recent concurrent works. Our work demonstrates a feasible path towards a scalable solution to electronic structure calculation, validating the key technological features and identifying future challenges for this goal. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2212.08006v3-abstract-full').style.display = 'none'; document.getElementById('2212.08006v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 17 June, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 15 December, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">11 pages, 4 figures in the main text, and 29 pages supplementary materials with 17 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2208.10236">arXiv:2208.10236</a> <span> [<a href="https://arxiv.org/pdf/2208.10236">pdf</a>, <a href="https://arxiv.org/format/2208.10236">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/RevModPhys.94.035001">10.1103/RevModPhys.94.035001 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Micius quantum experiments in space </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Lu%2C+C">Chao-Yang Lu</a>, <a href="/search/quant-ph?searchtype=author&query=Cao%2C+Y">Yuan Cao</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Cheng-Zhi Peng</a>, <a href="/search/quant-ph?searchtype=author&query=Pan%2C+J">Jian-Wei Pan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2208.10236v1-abstract-short" style="display: inline;"> Quantum theory has been successfully validated in numerous laboratory experiments. But would such a theory, which excellently describes the behavior of microscopic physical systems, and its predicted phenomena such as quantum entanglement, be still applicable on very large length scales? From a practical perspective, how can quantum key distribution -- where the security of establishing secret key… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2208.10236v1-abstract-full').style.display = 'inline'; document.getElementById('2208.10236v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2208.10236v1-abstract-full" style="display: none;"> Quantum theory has been successfully validated in numerous laboratory experiments. But would such a theory, which excellently describes the behavior of microscopic physical systems, and its predicted phenomena such as quantum entanglement, be still applicable on very large length scales? From a practical perspective, how can quantum key distribution -- where the security of establishing secret keys between distant parties is ensured by the laws of quantum mechanics -- be made technologically useful on a global scale? Due to photon loss in optical fibers and terrestrial free space, the achievable distance using direct transmission of single photons has been limited to a few hundred kilometers. A promising route to testing quantum physics over long distances and in the relativistic regimes, and thus realizing flexible global-scale quantum networks is via the use of satellites and space-based technologies, where a significant advantage is that the photon loss and turbulence predominantly occurs in the lower ~ 10 km of the atmosphere, and most of the photons' transmission path in the space is virtually in vacuum with almost zero absorption and decoherence. In this Article, we review the progress in free-space quantum experiments, with a focus on the fast-developing Micius satellite-based quantum communications. The perspective of space-ground integrated quantum networks and fundamental quantum optics experiments in space conceivable with satellites are discussed. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2208.10236v1-abstract-full').style.display = 'none'; document.getElementById('2208.10236v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 August, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">This review article focuses on the Micius satellite project with exhaustive technical details, and discusses the future plans. 53 pages, 49 figures, 254 references</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Rev. Mod. Phys. 94, 035001 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2207.14142">arXiv:2207.14142</a> <span> [<a href="https://arxiv.org/pdf/2207.14142">pdf</a>, <a href="https://arxiv.org/format/2207.14142">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.130.110601">10.1103/PhysRevLett.130.110601 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Experimental Simulation of Larger Quantum Circuits with Fewer Superconducting Qubits </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Ying%2C+C">Chong Ying</a>, <a href="/search/quant-ph?searchtype=author&query=Cheng%2C+B">Bin Cheng</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+Y">Youwei Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+H">He-Liang Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Y">Yu-Ning Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Gong%2C+M">Ming Gong</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yulin Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+S">Shiyu Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Liang%2C+F">Futian Liang</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+J">Jin Lin</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+Y">Yu Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+H">Hui Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Rong%2C+H">Hao Rong</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Cheng-Zhi Peng</a>, <a href="/search/quant-ph?searchtype=author&query=Yung%2C+M">Man-Hong Yung</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+X">Xiaobo Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Pan%2C+J">Jian-Wei Pan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2207.14142v2-abstract-short" style="display: inline;"> Although near-term quantum computing devices are still limited by the quantity and quality of qubits in the so-called NISQ era, quantum computational advantage has been experimentally demonstrated. Moreover, hybrid architectures of quantum and classical computing have become the main paradigm for exhibiting NISQ applications, where low-depth quantum circuits are repeatedly applied. In order to fur… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.14142v2-abstract-full').style.display = 'inline'; document.getElementById('2207.14142v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2207.14142v2-abstract-full" style="display: none;"> Although near-term quantum computing devices are still limited by the quantity and quality of qubits in the so-called NISQ era, quantum computational advantage has been experimentally demonstrated. Moreover, hybrid architectures of quantum and classical computing have become the main paradigm for exhibiting NISQ applications, where low-depth quantum circuits are repeatedly applied. In order to further scale up the problem size solvable by the NISQ devices, it is also possible to reduce the number of physical qubits by "cutting" the quantum circuit into different pieces. In this work, we experimentally demonstrated a circuit-cutting method for simulating quantum circuits involving many logical qubits, using only a few physical superconducting qubits. By exploiting the symmetry of linear-cluster states, we can estimate the effectiveness of circuit-cutting for simulating up to 33-qubit linear-cluster states, using at most 4 physical qubits for each subcircuit. Specifically, for the 12-qubit linear-cluster state, we found that the experimental fidelity bound can reach as much as 0.734, which is about 19\% higher than a direct simulation {on the same} 12-qubit superconducting processor. Our results indicate that circuit-cutting represents a feasible approach of simulating quantum circuits using much fewer qubits, while achieving a much higher circuit fidelity. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.14142v2-abstract-full').style.display = 'none'; document.getElementById('2207.14142v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 1 March, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 28 July, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2022. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2205.13828">arXiv:2205.13828</a> <span> [<a href="https://arxiv.org/pdf/2205.13828">pdf</a>, <a href="https://arxiv.org/format/2205.13828">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Portable ground stations for space-to-ground quantum key distribution </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Ren%2C+J">Ji-Gang Ren</a>, <a href="/search/quant-ph?searchtype=author&query=Abulizi%2C+M">Maimaiti Abulizi</a>, <a href="/search/quant-ph?searchtype=author&query=Yong%2C+H">Hai-Lin Yong</a>, <a href="/search/quant-ph?searchtype=author&query=Yin%2C+J">Juan Yin</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xue-Jiao Li</a>, <a href="/search/quant-ph?searchtype=author&query=Jiang%2C+Y">Yuan Jiang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+W">Wei-Yang Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Xue%2C+H">Hua-Jian Xue</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Y">Yu-He Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Jin%2C+B">Biao Jin</a>, <a href="/search/quant-ph?searchtype=author&query=Yin%2C+Y">Ya-Yun Yin</a>, <a href="/search/quant-ph?searchtype=author&query=Tu%2C+Z">Zhou-Yu Tu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+X">Xiao-Juan Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+S">Shuang-Qiang Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+F">Feng-Zhi Li</a>, <a href="/search/quant-ph?searchtype=author&query=Liao%2C+S">Sheng-Kai Liao</a>, <a href="/search/quant-ph?searchtype=author&query=Cai%2C+W">Wen-Qi Cai</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+W">Wei-Yue Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Cao%2C+Y">Yuan Cao</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+F">Fei Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+L">Li Li</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+N">Nai-Le Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Q">Qiang Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Y">Yu-Ao Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Cheng-Zhi Peng</a> , et al. (1 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2205.13828v1-abstract-short" style="display: inline;"> Quantum key distribution (QKD) uses the fundamental principles of quantum mechanics to share unconditionally secure keys between distant users. Previous works based on the quantum science satellite "Micius" have initially demonstrated the feasibility of a global QKD network. However, the practical applications of space-based QKD still face many technical problems, such as the huge size and weight… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2205.13828v1-abstract-full').style.display = 'inline'; document.getElementById('2205.13828v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2205.13828v1-abstract-full" style="display: none;"> Quantum key distribution (QKD) uses the fundamental principles of quantum mechanics to share unconditionally secure keys between distant users. Previous works based on the quantum science satellite "Micius" have initially demonstrated the feasibility of a global QKD network. However, the practical applications of space-based QKD still face many technical problems, such as the huge size and weight of ground stations required to receive quantum signals. Here, we report space-to-ground QKD demonstrations based on portable receiving ground stations. The weight of the portable ground station is less than 100 kg, the space required is less than 1 m$^{3}$ and the installation time requires no more than 12 hours, all of the weight, required space and deployment time are about two orders of magnitude lower than those for the previous systems. Moreover, the equipment is easy to handle and can be placed on the roof of buildings in a metropolis. Secure keys have been successfully generated from the "Micius" satellite to these portable ground stations at six different places in China, and an average final secure key length is around 50 kb can be obtained during one passage. Our results pave the way for, and greatly accelerate the practical application of, space-based QKD. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2205.13828v1-abstract-full').style.display = 'none'; document.getElementById('2205.13828v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 May, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2022. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2204.06472">arXiv:2204.06472</a> <span> [<a href="https://arxiv.org/pdf/2204.06472">pdf</a>, <a href="https://arxiv.org/format/2204.06472">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Theory">hep-th</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1007/JHEP01(2023)003">10.1007/JHEP01(2023)003 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Matrix Entanglement </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Gautam%2C+V">Vaibhav Gautam</a>, <a href="/search/quant-ph?searchtype=author&query=Hanada%2C+M">Masanori Hanada</a>, <a href="/search/quant-ph?searchtype=author&query=Jevicki%2C+A">Antal Jevicki</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Cheng Peng</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2204.06472v2-abstract-short" style="display: inline;"> In gauge/gravity duality, matrix degrees of freedom on the gauge theory side play important roles for the emergent geometry. In this paper, we discuss how the entanglement on the gravity side can be described as the entanglement between matrix degrees of freedom. Our approach, which we call 'matrix entanglement', is different from 'target-space entanglement' proposed and discussed recently by seve… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2204.06472v2-abstract-full').style.display = 'inline'; document.getElementById('2204.06472v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2204.06472v2-abstract-full" style="display: none;"> In gauge/gravity duality, matrix degrees of freedom on the gauge theory side play important roles for the emergent geometry. In this paper, we discuss how the entanglement on the gravity side can be described as the entanglement between matrix degrees of freedom. Our approach, which we call 'matrix entanglement', is different from 'target-space entanglement' proposed and discussed recently by several groups. We consider several classes of quantum states to which our approach can play important roles. When applied to fuzzy sphere, matrix entanglement can be used to define the usual spatial entanglement in two-brane or five-brane world-volume theory nonperturbatively in a regularized setup. Another application is to a small black hole in AdS5*S5 that can evaporate without being attached to a heat bath, for which our approach suggests a gauge theory origin of the Page curve. The confined degrees of freedom in the partially-deconfined states play the important roles. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2204.06472v2-abstract-full').style.display = 'none'; document.getElementById('2204.06472v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 13 May, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 13 April, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">37 pages, 11 figures, references added</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> DMUS-MP-22/03 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2203.15246">arXiv:2203.15246</a> <span> [<a href="https://arxiv.org/pdf/2203.15246">pdf</a>, <a href="https://arxiv.org/format/2203.15246">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Data Structures and Algorithms">cs.DS</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3389/fphy.2022.906590">10.3389/fphy.2022.906590 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A quantum-inspired tensor network method for constrained combinatorial optimization problems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Hao%2C+T">Tianyi Hao</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+X">Xuxin Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Jia%2C+C">Chunjing Jia</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Cheng Peng</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2203.15246v2-abstract-short" style="display: inline;"> Combinatorial optimization is of general interest for both theoretical study and real-world applications. Fast-developing quantum algorithms provide a different perspective on solving combinatorial optimization problems. In this paper, we propose a quantum-inspired tensor-network-based algorithm for general locally constrained combinatorial optimization problems. Our algorithm constructs a Hamilto… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2203.15246v2-abstract-full').style.display = 'inline'; document.getElementById('2203.15246v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2203.15246v2-abstract-full" style="display: none;"> Combinatorial optimization is of general interest for both theoretical study and real-world applications. Fast-developing quantum algorithms provide a different perspective on solving combinatorial optimization problems. In this paper, we propose a quantum-inspired tensor-network-based algorithm for general locally constrained combinatorial optimization problems. Our algorithm constructs a Hamiltonian for the problem of interest, effectively mapping it to a quantum problem, then encodes the constraints directly into a tensor network state and solves the optimal solution by evolving the system to the ground state of the Hamiltonian. We demonstrate our algorithm with the open-pit mining problem, which results in a quadratic asymptotic time complexity. Our numerical results show the effectiveness of this construction and potential applications in further studies for general combinatorial optimization problems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2203.15246v2-abstract-full').style.display = 'none'; document.getElementById('2203.15246v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 September, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 29 March, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Frontiers in Physics, Volume 10, Article 906590 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2202.06616">arXiv:2202.06616</a> <span> [<a href="https://arxiv.org/pdf/2202.06616">pdf</a>, <a href="https://arxiv.org/format/2202.06616">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/0256-307X/39/3/030302">10.1088/0256-307X/39/3/030302 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Realization of fast all-microwave CZ gates with a tunable coupler </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shaowei Li</a>, <a href="/search/quant-ph?searchtype=author&query=Fan%2C+D">Daojin Fan</a>, <a href="/search/quant-ph?searchtype=author&query=Gong%2C+M">Ming Gong</a>, <a href="/search/quant-ph?searchtype=author&query=Ye%2C+Y">Yangsen Ye</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+X">Xiawei Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yulin Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Guan%2C+H">Huijie Guan</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+H">Hui Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Rong%2C+H">Hao Rong</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+H">He-Liang Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Zha%2C+C">Chen Zha</a>, <a href="/search/quant-ph?searchtype=author&query=Yan%2C+K">Kai Yan</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+S">Shaojun Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Qian%2C+H">Haoran Qian</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+H">Haibin Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+F">Fusheng Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+Q">Qingling Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+Y">Youwei Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+S">Shiyu Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Ying%2C+C">Chong Ying</a>, <a href="/search/quant-ph?searchtype=author&query=Cao%2C+S">Sirui Cao</a>, <a href="/search/quant-ph?searchtype=author&query=Yu%2C+J">Jiale Yu</a>, <a href="/search/quant-ph?searchtype=author&query=Liang%2C+F">Futian Liang</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+Y">Yu Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+J">Jin Lin</a> , et al. (7 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2202.06616v1-abstract-short" style="display: inline;"> The development of high-fidelity two-qubit quantum gates is essential for digital quantum computing. Here, we propose and realize an all-microwave parametric Controlled-Z (CZ) gates by coupling strength modulation in a superconducting Transmon qubit system with tunable couplers. After optimizing the design of the tunable coupler together with the control pulse numerically, we experimentally realiz… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2202.06616v1-abstract-full').style.display = 'inline'; document.getElementById('2202.06616v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2202.06616v1-abstract-full" style="display: none;"> The development of high-fidelity two-qubit quantum gates is essential for digital quantum computing. Here, we propose and realize an all-microwave parametric Controlled-Z (CZ) gates by coupling strength modulation in a superconducting Transmon qubit system with tunable couplers. After optimizing the design of the tunable coupler together with the control pulse numerically, we experimentally realized a 100 ns CZ gate with high fidelity of 99.38%$ \pm$0.34% and the control error being 0.1%. We note that our CZ gates are not affected by pulse distortion and do not need pulse correction, {providing a solution for the real-time pulse generation in a dynamic quantum feedback circuit}. With the expectation of utilizing our all-microwave control scheme to reduce the number of control lines through frequency multiplexing in the future, our scheme draws a blueprint for the high-integrable quantum hardware design. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2202.06616v1-abstract-full').style.display = 'none'; document.getElementById('2202.06616v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 February, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Chin. Phys. Lett.,39 (3): 030302 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2201.05957">arXiv:2201.05957</a> <span> [<a href="https://arxiv.org/pdf/2201.05957">pdf</a>, <a href="https://arxiv.org/format/2201.05957">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1016/j.scib.2023.04.003">10.1016/j.scib.2023.04.003 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Quantum Neuronal Sensing of Quantum Many-Body States on a 61-Qubit Programmable Superconducting Processor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Gong%2C+M">Ming Gong</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+H">He-Liang Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+S">Shiyu Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+C">Chu Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shaowei Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yulin Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+Q">Qingling Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+Y">Youwei Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+S">Shaojun Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Qian%2C+H">Haoran Qian</a>, <a href="/search/quant-ph?searchtype=author&query=Ye%2C+Y">Yangsen Ye</a>, <a href="/search/quant-ph?searchtype=author&query=Zha%2C+C">Chen Zha</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+F">Fusheng Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Ying%2C+C">Chong Ying</a>, <a href="/search/quant-ph?searchtype=author&query=Yu%2C+J">Jiale Yu</a>, <a href="/search/quant-ph?searchtype=author&query=Fan%2C+D">Daojin Fan</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+D">Dachao Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Su%2C+H">Hong Su</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+H">Hui Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Rong%2C+H">Hao Rong</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kaili Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Cao%2C+S">Sirui Cao</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+J">Jin Lin</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+Y">Yu Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Sun%2C+L">Lihua Sun</a> , et al. (11 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2201.05957v2-abstract-short" style="display: inline;"> Classifying many-body quantum states with distinct properties and phases of matter is one of the most fundamental tasks in quantum many-body physics. However, due to the exponential complexity that emerges from the enormous numbers of interacting particles, classifying large-scale quantum states has been extremely challenging for classical approaches. Here, we propose a new approach called quantum… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2201.05957v2-abstract-full').style.display = 'inline'; document.getElementById('2201.05957v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2201.05957v2-abstract-full" style="display: none;"> Classifying many-body quantum states with distinct properties and phases of matter is one of the most fundamental tasks in quantum many-body physics. However, due to the exponential complexity that emerges from the enormous numbers of interacting particles, classifying large-scale quantum states has been extremely challenging for classical approaches. Here, we propose a new approach called quantum neuronal sensing. Utilizing a 61 qubit superconducting quantum processor, we show that our scheme can efficiently classify two different types of many-body phenomena: namely the ergodic and localized phases of matter. Our quantum neuronal sensing process allows us to extract the necessary information coming from the statistical characteristics of the eigenspectrum to distinguish these phases of matter by measuring only one qubit. Our work demonstrates the feasibility and scalability of quantum neuronal sensing for near-term quantum processors and opens new avenues for exploring quantum many-body phenomena in larger-scale systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2201.05957v2-abstract-full').style.display = 'none'; document.getElementById('2201.05957v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 20 November, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 15 January, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">7 pages, 3 figures in the main text, and 13 pages, 13 figures, and 1 table in supplementary materials</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Science Bulletin, 68(9):906-912 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2112.13505">arXiv:2112.13505</a> <span> [<a href="https://arxiv.org/pdf/2112.13505">pdf</a>, <a href="https://arxiv.org/format/2112.13505">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.129.030501">10.1103/PhysRevLett.129.030501 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Realization of an Error-Correcting Surface Code with Superconducting Qubits </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+Y">Youwei Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Ye%2C+Y">Yangsen Ye</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+H">He-Liang Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Y">Yiming Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+D">Dachao Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Guan%2C+H">Huijie Guan</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+Q">Qingling Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Wei%2C+Z">Zuolin Wei</a>, <a href="/search/quant-ph?searchtype=author&query=He%2C+T">Tan He</a>, <a href="/search/quant-ph?searchtype=author&query=Cao%2C+S">Sirui Cao</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+F">Fusheng Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chung%2C+T">Tung-Hsun Chung</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+H">Hui Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Fan%2C+D">Daojin Fan</a>, <a href="/search/quant-ph?searchtype=author&query=Gong%2C+M">Ming Gong</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+C">Cheng Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+S">Shaojun Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Han%2C+L">Lianchen Han</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+N">Na Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shaowei Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yuan Li</a>, <a href="/search/quant-ph?searchtype=author&query=Liang%2C+F">Futian Liang</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+J">Jin Lin</a>, <a href="/search/quant-ph?searchtype=author&query=Qian%2C+H">Haoran Qian</a>, <a href="/search/quant-ph?searchtype=author&query=Rong%2C+H">Hao Rong</a> , et al. (14 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2112.13505v2-abstract-short" style="display: inline;"> Quantum error correction is a critical technique for transitioning from noisy intermediate-scale quantum (NISQ) devices to fully fledged quantum computers. The surface code, which has a high threshold error rate, is the leading quantum error correction code for two-dimensional grid architecture. So far, the repeated error correction capability of the surface code has not been realized experimental… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2112.13505v2-abstract-full').style.display = 'inline'; document.getElementById('2112.13505v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2112.13505v2-abstract-full" style="display: none;"> Quantum error correction is a critical technique for transitioning from noisy intermediate-scale quantum (NISQ) devices to fully fledged quantum computers. The surface code, which has a high threshold error rate, is the leading quantum error correction code for two-dimensional grid architecture. So far, the repeated error correction capability of the surface code has not been realized experimentally. Here, we experimentally implement an error-correcting surface code, the distance-3 surface code which consists of 17 qubits, on the \textit{Zuchongzhi} 2.1 superconducting quantum processor. By executing several consecutive error correction cycles, the logical error can be significantly reduced after applying corrections, achieving the repeated error correction of surface code for the first time. This experiment represents a fully functional instance of an error-correcting surface code, providing a key step on the path towards scalable fault-tolerant quantum computing. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2112.13505v2-abstract-full').style.display = 'none'; document.getElementById('2112.13505v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 29 January, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 26 December, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 129, 030501 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2109.04736">arXiv:2109.04736</a> <span> [<a href="https://arxiv.org/pdf/2109.04736">pdf</a>, <a href="https://arxiv.org/format/2109.04736">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41534-021-00474-3">10.1038/s41534-021-00474-3 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Implementation of a 46-node quantum metropolitan area network </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chen%2C+T">Teng-Yun Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Jiang%2C+X">Xiao Jiang</a>, <a href="/search/quant-ph?searchtype=author&query=Tang%2C+S">Shi-Biao Tang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+L">Lei Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Yuan%2C+X">Xiao Yuan</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+H">Hongyi Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+J">Jian Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+Y">Yang Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+L">Luo-Kan Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+W">Wei-Yue Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+H">Hong-Fei Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Cui%2C+K">Ke Cui</a>, <a href="/search/quant-ph?searchtype=author&query=Liang%2C+H">Hao Liang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xiao-Gang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Mao%2C+Y">Yingqiu Mao</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+L">Liu-Jun Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Feng%2C+S">Si-Bo Feng</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Q">Qing Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Q">Qiang Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+L">Li Li</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+N">Nai-Le Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Cheng-Zhi Peng</a>, <a href="/search/quant-ph?searchtype=author&query=Ma%2C+X">Xiongfeng Ma</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+Y">Yong Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Pan%2C+J">Jian-Wei Pan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2109.04736v1-abstract-short" style="display: inline;"> Quantum key distribution (QKD) enables secure key exchanges between two remote users. The ultimate goal of secure communication is to establish a global quantum network. The existing field tests suggest that quantum networks are feasible. To achieve a practical quantum network, we need to overcome several challenges, including realising versatile topologies for large scales, simple network mainten… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2109.04736v1-abstract-full').style.display = 'inline'; document.getElementById('2109.04736v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2109.04736v1-abstract-full" style="display: none;"> Quantum key distribution (QKD) enables secure key exchanges between two remote users. The ultimate goal of secure communication is to establish a global quantum network. The existing field tests suggest that quantum networks are feasible. To achieve a practical quantum network, we need to overcome several challenges, including realising versatile topologies for large scales, simple network maintenance, extendable configuration, and robustness to node failures. To this end, we present a field operation of a quantum metropolitan-area network with 46 nodes and show that all these challenges can be overcome with cutting-edge quantum technologies. In particular, we realise different topological structures and continuously run the network for 31 months, by employing standard equipment for network maintenance with an extendable configuration. We realise QKD pairing and key management with a sophisticated key control center. In this implementation, the final keys have been used for secure communication such as real-time voice telephone, text messaging, and file transmission with one-time pad encryption, which can support 11 pairs of users to make audio calls simultaneously. Combined with inter-city quantum backbone and ground-satellite links, our metropolitan implementation paves the way toward a global quantum network. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2109.04736v1-abstract-full').style.display = 'none'; document.getElementById('2109.04736v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 September, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">14 pages, 5 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> npj Quantum Information volume 7, 134 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2109.03494">arXiv:2109.03494</a> <span> [<a href="https://arxiv.org/pdf/2109.03494">pdf</a>, <a href="https://arxiv.org/format/2109.03494">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Quantum Computational Advantage via 60-Qubit 24-Cycle Random Circuit Sampling </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+Q">Qingling Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Cao%2C+S">Sirui Cao</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+F">Fusheng Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+M">Ming-Cheng Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+X">Xiawei Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chung%2C+T">Tung-Hsun Chung</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+H">Hui Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Du%2C+Y">Yajie Du</a>, <a href="/search/quant-ph?searchtype=author&query=Fan%2C+D">Daojin Fan</a>, <a href="/search/quant-ph?searchtype=author&query=Gong%2C+M">Ming Gong</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+C">Cheng Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+C">Chu Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+S">Shaojun Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Han%2C+L">Lianchen Han</a>, <a href="/search/quant-ph?searchtype=author&query=Hong%2C+L">Linyin Hong</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+H">He-Liang Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Huo%2C+Y">Yong-Heng Huo</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+L">Liping Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+N">Na Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shaowei Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yuan Li</a>, <a href="/search/quant-ph?searchtype=author&query=Liang%2C+F">Futian Liang</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+C">Chun Lin</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+J">Jin Lin</a>, <a href="/search/quant-ph?searchtype=author&query=Qian%2C+H">Haoran Qian</a> , et al. (28 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2109.03494v2-abstract-short" style="display: inline;"> To ensure a long-term quantum computational advantage, the quantum hardware should be upgraded to withstand the competition of continuously improved classical algorithms and hardwares. Here, we demonstrate a superconducting quantum computing systems \textit{Zuchongzhi} 2.1, which has 66 qubits in a two-dimensional array in a tunable coupler architecture. The readout fidelity of \textit{Zuchongzhi}… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2109.03494v2-abstract-full').style.display = 'inline'; document.getElementById('2109.03494v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2109.03494v2-abstract-full" style="display: none;"> To ensure a long-term quantum computational advantage, the quantum hardware should be upgraded to withstand the competition of continuously improved classical algorithms and hardwares. Here, we demonstrate a superconducting quantum computing systems \textit{Zuchongzhi} 2.1, which has 66 qubits in a two-dimensional array in a tunable coupler architecture. The readout fidelity of \textit{Zuchongzhi} 2.1 is considerably improved to an average of 97.74\%. The more powerful quantum processor enables us to achieve larger-scale random quantum circuit sampling, with a system scale of up to 60 qubits and 24 cycles. The achieved sampling task is about 6 orders of magnitude more difficult than that of Sycamore [Nature \textbf{574}, 505 (2019)] in the classic simulation, and 3 orders of magnitude more difficult than the sampling task on \textit{Zuchongzhi} 2.0 [arXiv:2106.14734 (2021)]. The time consumption of classically simulating random circuit sampling experiment using state-of-the-art classical algorithm and supercomputer is extended to tens of thousands of years (about $4.8\times 10^4$ years), while \textit{Zuchongzhi} 2.1 only takes about 4.2 hours, thereby significantly enhancing the quantum computational advantage. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2109.03494v2-abstract-full').style.display = 'none'; document.getElementById('2109.03494v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 9 September, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 8 September, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2021. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2109.00994">arXiv:2109.00994</a> <span> [<a href="https://arxiv.org/pdf/2109.00994">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> </div> <p class="title is-5 mathjax"> Quantum design for advanced qubits: plasmonium </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Liu%2C+F">Feng-Ming Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+M">Ming-Cheng Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+C">Can Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shao-Wei Li</a>, <a href="/search/quant-ph?searchtype=author&query=Shang%2C+Z">Zhong-Xia Shang</a>, <a href="/search/quant-ph?searchtype=author&query=Ying%2C+C">Chong Ying</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+J">Jian-Wen Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Cheng-Zhi Peng</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+X">Xiaobo Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Lu%2C+C">Chao-Yang Lu</a>, <a href="/search/quant-ph?searchtype=author&query=Pan%2C+J">Jian-Wei Pan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2109.00994v3-abstract-short" style="display: inline;"> The increasingly complex quantum electronic circuits with a number of coupled quantum degrees of freedom will become intractable to be simulated on classical computers, and requires quantum computers for an efficient simulation. In turn, it will be a central concept in quantum-aided design for next-generation quantum processors. Here, we demonstrate variational quantum eigensolvers to simulate sup… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2109.00994v3-abstract-full').style.display = 'inline'; document.getElementById('2109.00994v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2109.00994v3-abstract-full" style="display: none;"> The increasingly complex quantum electronic circuits with a number of coupled quantum degrees of freedom will become intractable to be simulated on classical computers, and requires quantum computers for an efficient simulation. In turn, it will be a central concept in quantum-aided design for next-generation quantum processors. Here, we demonstrate variational quantum eigensolvers to simulate superconducting quantum circuits with varying parameters covering a plasmon-transition regime, which reveals an advanced post-transmon qubit, "plasmonium". We fabricate this new qubit and demonstrate that it exhibits not only high single- and two-qubit gate fidelities (99.85(1)% and 99.58(3)%, respectively), but also a shrinking (by 60%) physical size and larger (by 50%) anharmonicity than the transmon, which can bring a number of advantages for scaling up multi-qubit devices. Our work opens the way to designing advanced quantum processors using existing quantum computing resources. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2109.00994v3-abstract-full').style.display = 'none'; document.getElementById('2109.00994v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 August, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 2 September, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">We demonstrate quantum computer-aided design of a new high-performance superconducting quantum processor</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2107.07311">arXiv:2107.07311</a> <span> [<a href="https://arxiv.org/pdf/2107.07311">pdf</a>, <a href="https://arxiv.org/ps/2107.07311">ps</a>, <a href="https://arxiv.org/format/2107.07311">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevA.105.012418">10.1103/PhysRevA.105.012418 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Floquet Prethermal Phase Protected by U(1) Symmetry on a Superconducting Quantum Processor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Ying%2C+C">Chong Ying</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Q">Qihao Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shaowei Li</a>, <a href="/search/quant-ph?searchtype=author&query=Gong%2C+M">Ming Gong</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+X">Xiu-Hao Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+F">Fusheng Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Zha%2C+C">Chen Zha</a>, <a href="/search/quant-ph?searchtype=author&query=Ye%2C+Y">Yangsen Ye</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+C">Can Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+Q">Qingling Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+S">Shiyu Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+Y">Youwei Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Qian%2C+H">Haoran Qian</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+S">Shaojun Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yulin Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Rong%2C+H">Hao Rong</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+H">Hui Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Liang%2C+F">Futian Liang</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+J">Jin Lin</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+Y">Yu Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Cheng-Zhi Peng</a>, <a href="/search/quant-ph?searchtype=author&query=Lu%2C+C">Chao-Yang Lu</a>, <a href="/search/quant-ph?searchtype=author&query=Yin%2C+Z">Zhang-Qi Yin</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+X">Xiaobo Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Pan%2C+J">Jian-Wei Pan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2107.07311v1-abstract-short" style="display: inline;"> Periodically driven systems, or Floquet systems, exhibit many novel dynamics and interesting out-of-equilibrium phases of matter. Those phases arising with the quantum systems' symmetries, such as global $U(1)$ symmetry, can even show dynamical stability with symmetry-protection. Here we experimentally demonstrate a $U(1)$ symmetry-protected prethermal phase, via performing a digital-analog quantu… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2107.07311v1-abstract-full').style.display = 'inline'; document.getElementById('2107.07311v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2107.07311v1-abstract-full" style="display: none;"> Periodically driven systems, or Floquet systems, exhibit many novel dynamics and interesting out-of-equilibrium phases of matter. Those phases arising with the quantum systems' symmetries, such as global $U(1)$ symmetry, can even show dynamical stability with symmetry-protection. Here we experimentally demonstrate a $U(1)$ symmetry-protected prethermal phase, via performing a digital-analog quantum simulation on a superconducting quantum processor. The dynamical stability of this phase is revealed by its robustness against external perturbations. We also find that the spin glass order parameter in this phase is stabilized by the interaction between the spins. Our work reveals a promising prospect in discovering emergent quantum dynamical phases with digital-analog quantum simulators. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2107.07311v1-abstract-full').style.display = 'none'; document.getElementById('2107.07311v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 July, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">14 pages, 4 figures, and supplementary materials</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2106.14734">arXiv:2106.14734</a> <span> [<a href="https://arxiv.org/pdf/2106.14734">pdf</a>, <a href="https://arxiv.org/format/2106.14734">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.127.180501">10.1103/PhysRevLett.127.180501 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Strong quantum computational advantage using a superconducting quantum processor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yulin Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Bao%2C+W">Wan-Su Bao</a>, <a href="/search/quant-ph?searchtype=author&query=Cao%2C+S">Sirui Cao</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+F">Fusheng Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+M">Ming-Cheng Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+X">Xiawei Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chung%2C+T">Tung-Hsun Chung</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+H">Hui Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Du%2C+Y">Yajie Du</a>, <a href="/search/quant-ph?searchtype=author&query=Fan%2C+D">Daojin Fan</a>, <a href="/search/quant-ph?searchtype=author&query=Gong%2C+M">Ming Gong</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+C">Cheng Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+C">Chu Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+S">Shaojun Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Han%2C+L">Lianchen Han</a>, <a href="/search/quant-ph?searchtype=author&query=Hong%2C+L">Linyin Hong</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+H">He-Liang Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Huo%2C+Y">Yong-Heng Huo</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+L">Liping Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+N">Na Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shaowei Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yuan Li</a>, <a href="/search/quant-ph?searchtype=author&query=Liang%2C+F">Futian Liang</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+C">Chun Lin</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+J">Jin Lin</a> , et al. (29 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2106.14734v1-abstract-short" style="display: inline;"> Scaling up to a large number of qubits with high-precision control is essential in the demonstrations of quantum computational advantage to exponentially outpace the classical hardware and algorithmic improvements. Here, we develop a two-dimensional programmable superconducting quantum processor, \textit{Zuchongzhi}, which is composed of 66 functional qubits in a tunable coupling architecture. To… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2106.14734v1-abstract-full').style.display = 'inline'; document.getElementById('2106.14734v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2106.14734v1-abstract-full" style="display: none;"> Scaling up to a large number of qubits with high-precision control is essential in the demonstrations of quantum computational advantage to exponentially outpace the classical hardware and algorithmic improvements. Here, we develop a two-dimensional programmable superconducting quantum processor, \textit{Zuchongzhi}, which is composed of 66 functional qubits in a tunable coupling architecture. To characterize the performance of the whole system, we perform random quantum circuits sampling for benchmarking, up to a system size of 56 qubits and 20 cycles. The computational cost of the classical simulation of this task is estimated to be 2-3 orders of magnitude higher than the previous work on 53-qubit Sycamore processor [Nature \textbf{574}, 505 (2019)]. We estimate that the sampling task finished by \textit{Zuchongzhi} in about 1.2 hours will take the most powerful supercomputer at least 8 years. Our work establishes an unambiguous quantum computational advantage that is infeasible for classical computation in a reasonable amount of time. The high-precision and programmable quantum computing platform opens a new door to explore novel many-body phenomena and implement complex quantum algorithms. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2106.14734v1-abstract-full').style.display = 'none'; document.getElementById('2106.14734v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 28 June, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2021. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2103.08123">arXiv:2103.08123</a> <span> [<a href="https://arxiv.org/pdf/2103.08123">pdf</a>, <a href="https://arxiv.org/format/2103.08123">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mathematical Physics">math-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.128.040403">10.1103/PhysRevLett.128.040403 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Ruling out real-valued standard formalism of quantum theory </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chen%2C+M">Ming-Cheng Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+C">Can Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+F">Feng-Ming Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+J">Jian-Wen Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Ying%2C+C">Chong Ying</a>, <a href="/search/quant-ph?searchtype=author&query=Shang%2C+Z">Zhong-Xia Shang</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yulin Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Gong%2C+M">Ming Gong</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+H">Hui Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Liang%2C+F">Futian Liang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Q">Qiang Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Cheng-Zhi Peng</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+X">Xiaobo Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Cabello%2C+A">Adan Cabello</a>, <a href="/search/quant-ph?searchtype=author&query=Lu%2C+C">Chao-Yang Lu</a>, <a href="/search/quant-ph?searchtype=author&query=Pan%2C+J">Jian-Wei Pan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2103.08123v3-abstract-short" style="display: inline;"> Standard quantum theory was formulated with complex-valued Schrodinger equations, wave functions, operators, and Hilbert spaces. Previous work attempted to simulate quantum systems using only real numbers by exploiting an enlarged Hilbert space. A fundamental question arises: are complex numbers really necessary in the standard formalism of quantum theory? To answer this question, a quantum game h… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2103.08123v3-abstract-full').style.display = 'inline'; document.getElementById('2103.08123v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2103.08123v3-abstract-full" style="display: none;"> Standard quantum theory was formulated with complex-valued Schrodinger equations, wave functions, operators, and Hilbert spaces. Previous work attempted to simulate quantum systems using only real numbers by exploiting an enlarged Hilbert space. A fundamental question arises: are complex numbers really necessary in the standard formalism of quantum theory? To answer this question, a quantum game has been developed to distinguish standard quantum theory from its real-number analog by revealing a contradiction in the maximum game scores between a high-fidelity multi-qubit quantum experiment and players using only real-number quantum theory. Here, using superconducting qubits, we faithfully experimentally implement the quantum game based on entanglement swapping with a state-of-the-art fidelity of 0.952(1), which beats the real-number bound of 7.66 by 43 standard deviations. Our results disprove the real-number formulation and establish the indispensable role of complex numbers in the standard quantum theory. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2103.08123v3-abstract-full').style.display = 'none'; document.getElementById('2103.08123v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 February, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 14 March, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">submitted on March 2021</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 128, 040403 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2102.08587">arXiv:2102.08587</a> <span> [<a href="https://arxiv.org/pdf/2102.08587">pdf</a>, <a href="https://arxiv.org/format/2102.08587">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.127.020602">10.1103/PhysRevLett.127.020602 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Observation of strong and weak thermalization in a superconducting quantum processor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chen%2C+F">Fusheng Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Sun%2C+Z">Zheng-Hang Sun</a>, <a href="/search/quant-ph?searchtype=author&query=Gong%2C+M">Ming Gong</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+Q">Qingling Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Y">Yu-Ran Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yulin Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Ye%2C+Y">Yangsen Ye</a>, <a href="/search/quant-ph?searchtype=author&query=Zha%2C+C">Chen Zha</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shaowei Li</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+S">Shaojun Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Qian%2C+H">Haoran Qian</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+H">He-Liang Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Yu%2C+J">Jiale Yu</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+H">Hui Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Rong%2C+H">Hao Rong</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+J">Jin Lin</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+Y">Yu Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Sun%2C+L">Lihua Sun</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+C">Cheng Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+N">Na Li</a>, <a href="/search/quant-ph?searchtype=author&query=Liang%2C+F">Futian Liang</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Cheng-Zhi Peng</a>, <a href="/search/quant-ph?searchtype=author&query=Fan%2C+H">Heng Fan</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+X">Xiaobo Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Pan%2C+J">Jian-Wei Pan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2102.08587v1-abstract-short" style="display: inline;"> We experimentally study the ergodic dynamics of a 1D array of 12 superconducting qubits with a transverse field, and identify the regimes of strong and weak thermalization with different initial states. We observe convergence of the local observable to its thermal expectation value in the strong-thermalizaion regime. For weak thermalization, the dynamics of local observable exhibits an oscillation… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2102.08587v1-abstract-full').style.display = 'inline'; document.getElementById('2102.08587v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2102.08587v1-abstract-full" style="display: none;"> We experimentally study the ergodic dynamics of a 1D array of 12 superconducting qubits with a transverse field, and identify the regimes of strong and weak thermalization with different initial states. We observe convergence of the local observable to its thermal expectation value in the strong-thermalizaion regime. For weak thermalization, the dynamics of local observable exhibits an oscillation around the thermal value, which can only be attained by the time average. We also demonstrate that the entanglement entropy and concurrence can characterize the regimes of strong and weak thermalization. Our work provides an essential step towards a generic understanding of thermalization in quantum systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2102.08587v1-abstract-full').style.display = 'none'; document.getElementById('2102.08587v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 17 February, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">6+6 pages, 4+8 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 127, 020602 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2102.02573">arXiv:2102.02573</a> <span> [<a href="https://arxiv.org/pdf/2102.02573">pdf</a>, <a href="https://arxiv.org/format/2102.02573">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1126/science.abg7812">10.1126/science.abg7812 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Quantum walks on a programmable two-dimensional 62-qubit superconducting processor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Gong%2C+M">Ming Gong</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+S">Shiyu Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zha%2C+C">Chen Zha</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+M">Ming-Cheng Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+H">He-Liang Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yulin Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+Q">Qingling Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+Y">Youwei Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shaowei Li</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+S">Shaojun Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Qian%2C+H">Haoran Qian</a>, <a href="/search/quant-ph?searchtype=author&query=Ye%2C+Y">Yangsen Ye</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+F">Fusheng Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Ying%2C+C">Chong Ying</a>, <a href="/search/quant-ph?searchtype=author&query=Yu%2C+J">Jiale Yu</a>, <a href="/search/quant-ph?searchtype=author&query=Fan%2C+D">Daojin Fan</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+D">Dachao Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Su%2C+H">Hong Su</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+H">Hui Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Rong%2C+H">Hao Rong</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kaili Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Cao%2C+S">Sirui Cao</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+J">Jin Lin</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+Y">Yu Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Sun%2C+L">Lihua Sun</a> , et al. (11 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2102.02573v3-abstract-short" style="display: inline;"> Quantum walks are the quantum mechanical analogue of classical random walks and an extremely powerful tool in quantum simulations, quantum search algorithms, and even for universal quantum computing. In our work, we have designed and fabricated an 8x8 two-dimensional square superconducting qubit array composed of 62 functional qubits. We used this device to demonstrate high fidelity single and two… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2102.02573v3-abstract-full').style.display = 'inline'; document.getElementById('2102.02573v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2102.02573v3-abstract-full" style="display: none;"> Quantum walks are the quantum mechanical analogue of classical random walks and an extremely powerful tool in quantum simulations, quantum search algorithms, and even for universal quantum computing. In our work, we have designed and fabricated an 8x8 two-dimensional square superconducting qubit array composed of 62 functional qubits. We used this device to demonstrate high fidelity single and two particle quantum walks. Furthermore, with the high programmability of the quantum processor, we implemented a Mach-Zehnder interferometer where the quantum walker coherently traverses in two paths before interfering and exiting. By tuning the disorders on the evolution paths, we observed interference fringes with single and double walkers. Our work is an essential milestone in the field, brings future larger scale quantum applications closer to realization on these noisy intermediate-scale quantum processors. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2102.02573v3-abstract-full').style.display = 'none'; document.getElementById('2102.02573v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 July, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 4 February, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, 4 figures, and supplementary materials with 21 pages, 13 figures and 1 table</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Science 372, 948-952 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2101.08031">arXiv:2101.08031</a> <span> [<a href="https://arxiv.org/pdf/2101.08031">pdf</a>, <a href="https://arxiv.org/format/2101.08031">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.128.160502">10.1103/PhysRevLett.128.160502 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Observation of thermalization and information scrambling in a superconducting quantum processor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+Q">Qingling Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Sun%2C+Z">Zheng-Hang Sun</a>, <a href="/search/quant-ph?searchtype=author&query=Gong%2C+M">Ming Gong</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+F">Fusheng Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Y">Yu-Ran Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yulin Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Ye%2C+Y">Yangsen Ye</a>, <a href="/search/quant-ph?searchtype=author&query=Zha%2C+C">Chen Zha</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shaowei Li</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+S">Shaojun Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Qian%2C+H">Haoran Qian</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+H">He-Liang Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Yu%2C+J">Jiale Yu</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+H">Hui Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Rong%2C+H">Hao Rong</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+J">Jin Lin</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+Y">Yu Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Sun%2C+L">Lihua Sun</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+C">Cheng Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+N">Na Li</a>, <a href="/search/quant-ph?searchtype=author&query=Liang%2C+F">Futian Liang</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Cheng-Zhi Peng</a>, <a href="/search/quant-ph?searchtype=author&query=Fan%2C+H">Heng Fan</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+X">Xiaobo Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Pan%2C+J">Jian-Wei Pan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2101.08031v1-abstract-short" style="display: inline;"> Understanding various phenomena in non-equilibrium dynamics of closed quantum many-body systems, such as quantum thermalization, information scrambling, and nonergodic dynamics, is a crucial for modern physics. Using a ladder-type superconducting quantum processor, we perform analog quantum simulations of both the $XX$ ladder and one-dimensional (1D) $XX$ model. By measuring the dynamics of local… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2101.08031v1-abstract-full').style.display = 'inline'; document.getElementById('2101.08031v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2101.08031v1-abstract-full" style="display: none;"> Understanding various phenomena in non-equilibrium dynamics of closed quantum many-body systems, such as quantum thermalization, information scrambling, and nonergodic dynamics, is a crucial for modern physics. Using a ladder-type superconducting quantum processor, we perform analog quantum simulations of both the $XX$ ladder and one-dimensional (1D) $XX$ model. By measuring the dynamics of local observables, entanglement entropy and tripartite mutual information, we signal quantum thermalization and information scrambling in the $XX$ ladder. In contrast, we show that the $XX$ chain, as free fermions on a 1D lattice, fails to thermalize, and local information does not scramble in the integrable channel. Our experiments reveal ergodicity and scrambling in the controllable qubit ladder, and opens the door to further investigations on the thermodynamics and chaos in quantum many-body systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2101.08031v1-abstract-full').style.display = 'none'; document.getElementById('2101.08031v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 20 January, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">5 pages, 4 figures, and supplementary materials with 10 pages, 3 tables and 14 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 128, 160502 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2101.03460">arXiv:2101.03460</a> <span> [<a href="https://arxiv.org/pdf/2101.03460">pdf</a>, <a href="https://arxiv.org/format/2101.03460">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41534-019-0208-1">10.1038/s41534-019-0208-1 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Quantum Random Number Generation with Uncharacterized Laser and Sunlight </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yu-Huai Li</a>, <a href="/search/quant-ph?searchtype=author&query=Han%2C+X">Xuan Han</a>, <a href="/search/quant-ph?searchtype=author&query=Cao%2C+Y">Yuan Cao</a>, <a href="/search/quant-ph?searchtype=author&query=Yuan%2C+X">Xiao Yuan</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zheng-Ping Li</a>, <a href="/search/quant-ph?searchtype=author&query=Guan%2C+J">Jian-Yu Guan</a>, <a href="/search/quant-ph?searchtype=author&query=Yin%2C+J">Juan Yin</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Q">Qiang Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Ma%2C+X">Xiongfeng Ma</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Cheng-Zhi Peng</a>, <a href="/search/quant-ph?searchtype=author&query=Pan%2C+J">Jian-Wei Pan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2101.03460v1-abstract-short" style="display: inline;"> The entropy or randomness source is an essential ingredient in random number generation. Quantum random number generators generally require well modeled and calibrated light sources, such as a laser, to generate randomness. With uncharacterized light sources, such as sunlight or an uncharacterized laser, genuine randomness is practically hard to be quantified or extracted owing to its unknown or c… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2101.03460v1-abstract-full').style.display = 'inline'; document.getElementById('2101.03460v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2101.03460v1-abstract-full" style="display: none;"> The entropy or randomness source is an essential ingredient in random number generation. Quantum random number generators generally require well modeled and calibrated light sources, such as a laser, to generate randomness. With uncharacterized light sources, such as sunlight or an uncharacterized laser, genuine randomness is practically hard to be quantified or extracted owing to its unknown or complicated structure. By exploiting a recently proposed source-independent randomness generation protocol, we theoretically modify it by considering practical issues and experimentally realize the modified scheme with an uncharacterized laser and a sunlight source. The extracted randomness is guaranteed to be secure independent of its source and the randomness generation speed reaches 1 Mbps, three orders of magnitude higher than the original realization. Our result signifies the power of quantum technology in randomness generation and paves the way to high-speed semi-self-testing quantum random number generators with practical light sources. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2101.03460v1-abstract-full').style.display = 'none'; document.getElementById('2101.03460v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 9 January, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">24 pages, 5 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> npj Quantum Information 5, 97 (2019) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2012.11521">arXiv:2012.11521</a> <span> [<a href="https://arxiv.org/pdf/2012.11521">pdf</a>, <a href="https://arxiv.org/format/2012.11521">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevResearch.3.033043">10.1103/PhysRevResearch.3.033043 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Experimental characterization of quantum many-body localization transition </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Gong%2C+M">Ming Gong</a>, <a href="/search/quant-ph?searchtype=author&query=Neto%2C+G+D+d+M">Gentil D. de Moraes Neto</a>, <a href="/search/quant-ph?searchtype=author&query=Zha%2C+C">Chen Zha</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yulin Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Rong%2C+H">Hao Rong</a>, <a href="/search/quant-ph?searchtype=author&query=Ye%2C+Y">Yangsen Ye</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shaowei Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+Q">Qingling Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+S">Shiyu Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+Y">Youwei Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Liang%2C+F">Futian Liang</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+J">Jin Lin</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+Y">Yu Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Cheng-Zhi Peng</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+H">Hui Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Bayat%2C+A">Abolfazl Bayat</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+X">Xiaobo Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Pan%2C+J">Jian-Wei Pan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2012.11521v1-abstract-short" style="display: inline;"> As strength of disorder enhances beyond a threshold value in many-body systems, a fundamental transformation happens through which the entire spectrum localizes, a phenomenon known as many-body localization. This has profound implications as it breaks down fundamental principles of statistical mechanics, such as thermalization and ergodicity. Due to the complexity of the problem, the investigation… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2012.11521v1-abstract-full').style.display = 'inline'; document.getElementById('2012.11521v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2012.11521v1-abstract-full" style="display: none;"> As strength of disorder enhances beyond a threshold value in many-body systems, a fundamental transformation happens through which the entire spectrum localizes, a phenomenon known as many-body localization. This has profound implications as it breaks down fundamental principles of statistical mechanics, such as thermalization and ergodicity. Due to the complexity of the problem, the investigation of the many-body localization transition has remained a big challenge. The experimental exploration of the transition point is even more challenging as most of the proposed quantities for studying such effect are practically infeasible. Here, we experimentally implement a scalable protocol for detecting the many-body localization transition point, using the dynamics of a $N=12$ superconducting qubit array. We show that the sensitivity of the dynamics to random samples becomes maximum at the transition point which leaves its fingerprints in all spatial scales. By exploiting three quantities, each with different spatial resolution, we identify the transition point with excellent match between simulation and experiment. In addition, one can detect the evidence of mobility edge through slight variation of the transition point as the initial state varies. The protocol is easily scalable and can be performed across various physical platforms. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2012.11521v1-abstract-full').style.display = 'none'; document.getElementById('2012.11521v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 December, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">7 pages and 4 figures together with supplementary materials</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Research 3, 033043 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2012.04394">arXiv:2012.04394</a> <span> [<a href="https://arxiv.org/pdf/2012.04394">pdf</a>, <a href="https://arxiv.org/format/2012.04394">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1364/OE.411939">10.1364/OE.411939 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Single-mode fiber coupling with a M-SPGD algorithm for long-range quantum communications </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Yang%2C+K">Kui-Xing Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Abulizi%2C+M">Maimaiti Abulizi</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yu-Huai Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+B">Bo-Yang Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shuang-Lin Li</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+W">Wei-Yue Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Yin%2C+J">Juan Yin</a>, <a href="/search/quant-ph?searchtype=author&query=Cao%2C+Y">Yuan Cao</a>, <a href="/search/quant-ph?searchtype=author&query=Ren%2C+J">Ji-Gang Ren</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Cheng-Zhi Peng</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2012.04394v1-abstract-short" style="display: inline;"> Satellite-based quantum communication is a promising approach for realizing global-scale quantum networks. For free-space quantum channel, single-mode fiber coupling is particularly important for improving signal-to-noise ratio of daylight quantum key distribution (QKD) and compatibility with standard fiber-based QKD. However, achieving a highly efficient and stable single-mode coupling efficiency… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2012.04394v1-abstract-full').style.display = 'inline'; document.getElementById('2012.04394v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2012.04394v1-abstract-full" style="display: none;"> Satellite-based quantum communication is a promising approach for realizing global-scale quantum networks. For free-space quantum channel, single-mode fiber coupling is particularly important for improving signal-to-noise ratio of daylight quantum key distribution (QKD) and compatibility with standard fiber-based QKD. However, achieving a highly efficient and stable single-mode coupling efficiency under strong atmospheric turbulence remains experimentally challenging. Here, we develop a single-mode receiver with an adaptive optics (AO) system based on a modal version of the stochastic parallel gradient descent (M-SPGD) algorithm and test its performance over an 8 km urban terrestrial free-space channel. Under strong atmospheric turbulence, the M-SPGD AO system obtains an improvement of about 3.7 dB in the single-mode fiber coupling efficiency and a significant suppression of fluctuation, which can find its applications in free-space long-range quantum communications. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2012.04394v1-abstract-full').style.display = 'none'; document.getElementById('2012.04394v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 8 December, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">11 pages, 5 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Optics Express 28, 24, 36600 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2010.06201">arXiv:2010.06201</a> <span> [<a href="https://arxiv.org/pdf/2010.06201">pdf</a>, <a href="https://arxiv.org/format/2010.06201">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Computer Vision and Pattern Recognition">cs.CV</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Machine Learning">cs.LG</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevApplied.16.024051">10.1103/PhysRevApplied.16.024051 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Experimental Quantum Generative Adversarial Networks for Image Generation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Huang%2C+H">He-Liang Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Du%2C+Y">Yuxuan Du</a>, <a href="/search/quant-ph?searchtype=author&query=Gong%2C+M">Ming Gong</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+Y">Youwei Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yulin Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+C">Chaoyue Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shaowei Li</a>, <a href="/search/quant-ph?searchtype=author&query=Liang%2C+F">Futian Liang</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+J">Jin Lin</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+Y">Yu Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+R">Rui Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+T">Tongliang Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Hsieh%2C+M">Min-Hsiu Hsieh</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+H">Hui Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Rong%2C+H">Hao Rong</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Cheng-Zhi Peng</a>, <a href="/search/quant-ph?searchtype=author&query=Lu%2C+C">Chao-Yang Lu</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Y">Yu-Ao Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Tao%2C+D">Dacheng Tao</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+X">Xiaobo Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Pan%2C+J">Jian-Wei Pan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2010.06201v3-abstract-short" style="display: inline;"> Quantum machine learning is expected to be one of the first practical applications of near-term quantum devices. Pioneer theoretical works suggest that quantum generative adversarial networks (GANs) may exhibit a potential exponential advantage over classical GANs, thus attracting widespread attention. However, it remains elusive whether quantum GANs implemented on near-term quantum devices can ac… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2010.06201v3-abstract-full').style.display = 'inline'; document.getElementById('2010.06201v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2010.06201v3-abstract-full" style="display: none;"> Quantum machine learning is expected to be one of the first practical applications of near-term quantum devices. Pioneer theoretical works suggest that quantum generative adversarial networks (GANs) may exhibit a potential exponential advantage over classical GANs, thus attracting widespread attention. However, it remains elusive whether quantum GANs implemented on near-term quantum devices can actually solve real-world learning tasks. Here, we devise a flexible quantum GAN scheme to narrow this knowledge gap, which could accomplish image generation with arbitrarily high-dimensional features, and could also take advantage of quantum superposition to train multiple examples in parallel. For the first time, we experimentally achieve the learning and generation of real-world hand-written digit images on a superconducting quantum processor. Moreover, we utilize a gray-scale bar dataset to exhibit the competitive performance between quantum GANs and the classical GANs based on multilayer perceptron and convolutional neural network architectures, respectively, benchmarked by the Fr茅chet Distance score. Our work provides guidance for developing advanced quantum generative models on near-term quantum devices and opens up an avenue for exploring quantum advantages in various GAN-related learning tasks. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2010.06201v3-abstract-full').style.display = 'none'; document.getElementById('2010.06201v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 7 September, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 13 October, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">This work was completed in 2019, and the first version of manuscript was submitted to the journal in January 2020</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Applied 16, 024051 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2009.07590">arXiv:2009.07590</a> <span> [<a href="https://arxiv.org/pdf/2009.07590">pdf</a>, <a href="https://arxiv.org/format/2009.07590">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.126.090502">10.1103/PhysRevLett.126.090502 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Emulating quantum teleportation of a Majorana zero mode qubit </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Huang%2C+H">He-Liang Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Narozniak%2C+M">Marek Narozniak</a>, <a href="/search/quant-ph?searchtype=author&query=Liang%2C+F">Futian Liang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+Y">Youwei Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Castellano%2C+A+D">Anthony D. Castellano</a>, <a href="/search/quant-ph?searchtype=author&query=Gong%2C+M">Ming Gong</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yulin Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+S">Shiyu Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+J">Jin Lin</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+Y">Yu Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+H">Hui Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Rong%2C+H">Hao Rong</a>, <a href="/search/quant-ph?searchtype=author&query=Dowling%2C+J+P">Jonathan P. Dowling</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Cheng-Zhi Peng</a>, <a href="/search/quant-ph?searchtype=author&query=Byrnes%2C+T">Tim Byrnes</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+X">Xiaobo Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Pan%2C+J">Jian-Wei Pan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2009.07590v2-abstract-short" style="display: inline;"> Topological quantum computation based on anyons is a promising approach to achieve fault-tolerant quantum computing. The Majorana zero modes in the Kitaev chain are an example of non-Abelian anyons where braiding operations can be used to perform quantum gates. Here we perform a quantum simulation of topological quantum computing, by teleporting a qubit encoded in the Majorana zero modes of a Kita… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2009.07590v2-abstract-full').style.display = 'inline'; document.getElementById('2009.07590v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2009.07590v2-abstract-full" style="display: none;"> Topological quantum computation based on anyons is a promising approach to achieve fault-tolerant quantum computing. The Majorana zero modes in the Kitaev chain are an example of non-Abelian anyons where braiding operations can be used to perform quantum gates. Here we perform a quantum simulation of topological quantum computing, by teleporting a qubit encoded in the Majorana zero modes of a Kitaev chain. The quantum simulation is performed by mapping the Kitaev chain to its equivalent spin version, and realizing the ground states in a superconducting quantum processor. The teleportation transfers the quantum state encoded in the spin-mapped version of the Majorana zero mode states between two Kitaev chains. The teleportation circuit is realized using only braiding operations, and can be achieved despite being restricted to Clifford gates for the Ising anyons. The Majorana encoding is a quantum error detecting code for phase flip errors, which is used to improve the average fidelity of the teleportation for six distinct states from $70.76 \pm 0.35 \% $ to $84.60 \pm 0.11 \%$, well beyond the classical bound in either case. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2009.07590v2-abstract-full').style.display = 'none'; document.getElementById('2009.07590v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 9 December, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 16 September, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">comments are welcome</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 126, 090502 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2006.12863">arXiv:2006.12863</a> <span> [<a href="https://arxiv.org/pdf/2006.12863">pdf</a>, <a href="https://arxiv.org/format/2006.12863">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevApplied.15.034081">10.1103/PhysRevApplied.15.034081 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Experimental quantum key distribution secure against malicious devices </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+W">Wei Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zapatero%2C+V">Victor Zapatero</a>, <a href="/search/quant-ph?searchtype=author&query=Tan%2C+H">Hao Tan</a>, <a href="/search/quant-ph?searchtype=author&query=Wei%2C+K">Kejin Wei</a>, <a href="/search/quant-ph?searchtype=author&query=Min%2C+H">Hao Min</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+W">Wei-Yue Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Jiang%2C+X">Xiao Jiang</a>, <a href="/search/quant-ph?searchtype=author&query=Liao%2C+S">Sheng-Kai Liao</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Cheng-Zhi Peng</a>, <a href="/search/quant-ph?searchtype=author&query=Curty%2C+M">Marcos Curty</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+F">Feihu Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Pan%2C+J">Jian-Wei Pan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2006.12863v1-abstract-short" style="display: inline;"> The fabrication of quantum key distribution (QKD) systems typically involves several parties, thus providing Eve with multiple opportunities to meddle with the devices. As a consequence, conventional hardware and/or software hacking attacks pose natural threats to the security of practical QKD. Fortunately, if the number of corrupted devices is limited, the security can be restored by using redund… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2006.12863v1-abstract-full').style.display = 'inline'; document.getElementById('2006.12863v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2006.12863v1-abstract-full" style="display: none;"> The fabrication of quantum key distribution (QKD) systems typically involves several parties, thus providing Eve with multiple opportunities to meddle with the devices. As a consequence, conventional hardware and/or software hacking attacks pose natural threats to the security of practical QKD. Fortunately, if the number of corrupted devices is limited, the security can be restored by using redundant apparatuses. Here, we report on the demonstration of a secure QKD setup with optical devices and classical post-processing units possibly controlled by an eavesdropper. We implement a 1.25 GHz chip-based measurement-device-independent QKD system secure against malicious devices on \emph{both} the measurement and the users' sides. The secret key rate reaches 137 bps over a 24 dB channel loss. Our setup, benefiting from high clock rate, miniaturized transmitters and a cost-effective structure, provides a promising solution for widespread applications requiring uncompromising communication security. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2006.12863v1-abstract-full').style.display = 'none'; document.getElementById('2006.12863v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 23 June, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">28 pages, 5 figures, 4 tables</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Applied 15, 034081 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2006.05088">arXiv:2006.05088</a> <span> [<a href="https://arxiv.org/pdf/2006.05088">pdf</a>, <a href="https://arxiv.org/format/2006.05088">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.125.260503">10.1103/PhysRevLett.125.260503 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Long-distance free-space measurement-device-independent quantum key distribution </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Cao%2C+Y">Yuan Cao</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yu-Huai Li</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+K">Kui-Xing Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Jiang%2C+Y">Yang-Fan Jiang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shuang-Lin Li</a>, <a href="/search/quant-ph?searchtype=author&query=Hu%2C+X">Xiao-Long Hu</a>, <a href="/search/quant-ph?searchtype=author&query=Abulizi%2C+M">Maimaiti Abulizi</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+C">Cheng-Long Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+W">Weijun Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Sun%2C+Q">Qi-Chao Sun</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+W">Wei-Yue Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Jiang%2C+X">Xiao Jiang</a>, <a href="/search/quant-ph?searchtype=author&query=Liao%2C+S">Sheng-Kai Liao</a>, <a href="/search/quant-ph?searchtype=author&query=Ren%2C+J">Ji-Gang Ren</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+H">Hao Li</a>, <a href="/search/quant-ph?searchtype=author&query=You%2C+L">Lixing You</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zhen Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Yin%2C+J">Juan Yin</a>, <a href="/search/quant-ph?searchtype=author&query=Lu%2C+C">Chao-Yang Lu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+X">Xiang-Bin Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Q">Qiang Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Cheng-Zhi Peng</a>, <a href="/search/quant-ph?searchtype=author&query=Pan%2C+J">Jian-Wei Pan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2006.05088v1-abstract-short" style="display: inline;"> Measurement-device-independent quantum key distribution (MDI-QKD), based on two-photon interference, is immune to all attacks against the detection system and allows a QKD network with untrusted relays. Since the MDI-QKD protocol was proposed, fibre-based implementations have been rapidly developed towards longer distance, higher key rates, and network verification. However, owing to the effect of… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2006.05088v1-abstract-full').style.display = 'inline'; document.getElementById('2006.05088v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2006.05088v1-abstract-full" style="display: none;"> Measurement-device-independent quantum key distribution (MDI-QKD), based on two-photon interference, is immune to all attacks against the detection system and allows a QKD network with untrusted relays. Since the MDI-QKD protocol was proposed, fibre-based implementations have been rapidly developed towards longer distance, higher key rates, and network verification. However, owing to the effect of atmospheric turbulence, MDI-QKD over free-space channel remains experimentally challenging. Here, by developing the robust adaptive optics system, high precision time synchronization and frequency locking between independent photon sources located far apart, we realised the first free-space MDI-QKD over a 19.2-km urban atmospheric channel, which well exceeds the effective atmospheric thickness. Our experiment takes the first step towards satellite-based MDI-QKD. Moreover, the technology developed here opens the way to quantum experiments in free space involving long-distance interference of independent single photons. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2006.05088v1-abstract-full').style.display = 'none'; document.getElementById('2006.05088v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 9 June, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">14 pages, 3 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 125, 260503 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2006.00666">arXiv:2006.00666</a> <span> [<a href="https://arxiv.org/pdf/2006.00666">pdf</a>, <a href="https://arxiv.org/format/2006.00666">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41567-020-0892-y">10.1038/s41567-020-0892-y <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Towards satellite-based quantum-secure time transfer </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Dai%2C+H">Hui Dai</a>, <a href="/search/quant-ph?searchtype=author&query=Shen%2C+Q">Qi Shen</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+C">Chao-Ze Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shuang-Lin Li</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+W">Wei-Yue Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Cai%2C+W">Wen-Qi Cai</a>, <a href="/search/quant-ph?searchtype=author&query=Liao%2C+S">Sheng-Kai Liao</a>, <a href="/search/quant-ph?searchtype=author&query=Ren%2C+J">Ji-Gang Ren</a>, <a href="/search/quant-ph?searchtype=author&query=Yin%2C+J">Juan Yin</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Y">Yu-Ao Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Q">Qiang Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+F">Feihu Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Cheng-Zhi Peng</a>, <a href="/search/quant-ph?searchtype=author&query=Pan%2C+J">Jian-Wei Pan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2006.00666v1-abstract-short" style="display: inline;"> High-precision time synchronization for remote clocks plays an important role in fundamental science and real-life applications. However, the current time synchronization techniques have been shown to be vulnerable to sophisticated adversaries. There is a compelling need for fundamentally new methods to distribute high-precision time information securely. Here we propose a satellite-based quantum-… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2006.00666v1-abstract-full').style.display = 'inline'; document.getElementById('2006.00666v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2006.00666v1-abstract-full" style="display: none;"> High-precision time synchronization for remote clocks plays an important role in fundamental science and real-life applications. However, the current time synchronization techniques have been shown to be vulnerable to sophisticated adversaries. There is a compelling need for fundamentally new methods to distribute high-precision time information securely. Here we propose a satellite-based quantum-secure time transfer (QSTT) scheme based on two-way quantum key distribution (QKD) in free-space, and experimentally verify the key technologies of the scheme via the Micius quantum satellite. In QSTT, a quantum signal (e.g., single photon) is used as the carrier for both the time transfer and the secret-key generation, offering quantum-enhanced security for transferring time signal and time information. We perform a satellite-to-ground time synchronization using single-photon-level signals and achieve a quantum bit error rate of less than 1%, a time data rate of 9 kHz and a time-transfer precision of 30 ps. These results offer possibilities towards an enhanced infrastructure of time-transfer network, whose security stems from quantum physics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2006.00666v1-abstract-full').style.display = 'none'; document.getElementById('2006.00666v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 31 May, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Nature Physics in press</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Physics 16, 848 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2001.09169">arXiv:2001.09169</a> <span> [<a href="https://arxiv.org/pdf/2001.09169">pdf</a>, <a href="https://arxiv.org/format/2001.09169">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Disordered Systems and Neural Networks">cond-mat.dis-nn</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Statistical Mechanics">cond-mat.stat-mech</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.125.170503">10.1103/PhysRevLett.125.170503 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Ergodic-localized junctions in a periodically-driven spin chain </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zha%2C+C">Chen Zha</a>, <a href="/search/quant-ph?searchtype=author&query=Bastidas%2C+V+M">V. M. Bastidas</a>, <a href="/search/quant-ph?searchtype=author&query=Gong%2C+M">Ming Gong</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yulin Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Rong%2C+H">Hao Rong</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+R">Rui Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Ye%2C+Y">Yangsen Ye</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shaowei Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+Q">Qingling Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+S">Shiyu Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+Y">Youwei Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Liang%2C+F">Futian Liang</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+J">Jin Lin</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+Y">Yu Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Cheng-Zhi Peng</a>, <a href="/search/quant-ph?searchtype=author&query=Schmiedmayer%2C+J">Jorg Schmiedmayer</a>, <a href="/search/quant-ph?searchtype=author&query=Nemoto%2C+K">Kae Nemoto</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+H">Hui Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Munro%2C+W+J">W. J. Munro</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+X">Xiaobo Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Pan%2C+J">Jian-Wei Pan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2001.09169v3-abstract-short" style="display: inline;"> We report the analogue simulation of an ergodiclocalized junction by using an array of 12 coupled superconducting qubits. To perform the simulation, we fabricated a superconducting quantum processor that is divided into two domains: a driven domain representing an ergodic system, while the second is localized under the effect of disorder. Due to the overlap between localized and delocalized states… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2001.09169v3-abstract-full').style.display = 'inline'; document.getElementById('2001.09169v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2001.09169v3-abstract-full" style="display: none;"> We report the analogue simulation of an ergodiclocalized junction by using an array of 12 coupled superconducting qubits. To perform the simulation, we fabricated a superconducting quantum processor that is divided into two domains: a driven domain representing an ergodic system, while the second is localized under the effect of disorder. Due to the overlap between localized and delocalized states, for small disorder there is a proximity effect and localization is destroyed. To experimentally investigate this, we prepare a microwave excitation in the driven domain and explore how deep it can penetrate the disordered region by probing its dynamics. Furthermore, we performed an ensemble average over 50 realizations of disorder, which clearly shows the proximity effect. Our work opens a new avenue to build quantum simulators of driven-disordered systems with applications in condensed matter physics and material science <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2001.09169v3-abstract-full').style.display = 'none'; document.getElementById('2001.09169v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 February, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 24 January, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 125, 170503 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1912.06318">arXiv:1912.06318</a> <span> [<a href="https://arxiv.org/pdf/1912.06318">pdf</a>, <a href="https://arxiv.org/ps/1912.06318">ps</a>, <a href="https://arxiv.org/format/1912.06318">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1364/OE.28.000369">10.1364/OE.28.000369 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Polarization design for ground-to-satellite quantum entanglement distribution </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Han%2C+X">Xuan Han</a>, <a href="/search/quant-ph?searchtype=author&query=Yong%2C+H">Hai-Lin Yong</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+P">Ping Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+K">Kui-Xing Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shuang-Lin Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+W">Wei-Yang Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Xue%2C+H">Hua-Jian Xue</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+F">Feng-Zhi Li</a>, <a href="/search/quant-ph?searchtype=author&query=Ren%2C+J">Ji-Gang Ren</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Cheng-Zhi Peng</a>, <a href="/search/quant-ph?searchtype=author&query=Pan%2C+J">Jian-Wei Pan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1912.06318v1-abstract-short" style="display: inline;"> Polarization maintenance is a key technology for free-space quantum communication. In this paper, we describe a polarization maintenance design of a transmitting antenna with an average polarization extinction ratio of 887 : 1 by a local test. We implemented a feasible polarization-compensation scheme for satellite motions that has a polarization fidelity more than 0.995. Finally, we distribute en… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1912.06318v1-abstract-full').style.display = 'inline'; document.getElementById('1912.06318v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1912.06318v1-abstract-full" style="display: none;"> Polarization maintenance is a key technology for free-space quantum communication. In this paper, we describe a polarization maintenance design of a transmitting antenna with an average polarization extinction ratio of 887 : 1 by a local test. We implemented a feasible polarization-compensation scheme for satellite motions that has a polarization fidelity more than 0.995. Finally, we distribute entanglement to a satellite from ground for the first time with a violation of Bell inequality by 2.312+-0.096. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1912.06318v1-abstract-full').style.display = 'none'; document.getElementById('1912.06318v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 December, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">10 pages, 5 figures,</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1912.06317">arXiv:1912.06317</a> <span> [<a href="https://arxiv.org/pdf/1912.06317">pdf</a>, <a href="https://arxiv.org/format/1912.06317">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1364/OE.26.017044">10.1364/OE.26.017044 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Point-ahead demonstration of a transmitting antenna for satellite quantum communication </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Han%2C+X">Xuan Han</a>, <a href="/search/quant-ph?searchtype=author&query=Yong%2C+H">Hai-Lin Yong</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+P">Ping Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+W">Wei-Yang Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+K">Kui-Xing Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Xue%2C+H">Hua-Jian Xue</a>, <a href="/search/quant-ph?searchtype=author&query=Cai%2C+W">Wen-Qi Cai</a>, <a href="/search/quant-ph?searchtype=author&query=Ren%2C+J">Ji-Gang Ren</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Cheng-Zhi Peng</a>, <a href="/search/quant-ph?searchtype=author&query=Pan%2C+J">Jian-Wei Pan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1912.06317v1-abstract-short" style="display: inline;"> A low-divergence beam is an essential prerequisite for a high-efficiency longdistance optical link, particularly for satellite-based quantum communication. A point-ahead angle, caused by satellite motion, is always several times larger than the divergence angle of the signal beam. We design a novel transmitting antenna with a point-ahead function, and provide an easy-to-perform calibration method… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1912.06317v1-abstract-full').style.display = 'inline'; document.getElementById('1912.06317v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1912.06317v1-abstract-full" style="display: none;"> A low-divergence beam is an essential prerequisite for a high-efficiency longdistance optical link, particularly for satellite-based quantum communication. A point-ahead angle, caused by satellite motion, is always several times larger than the divergence angle of the signal beam. We design a novel transmitting antenna with a point-ahead function, and provide an easy-to-perform calibration method with an accuracy better than 0.2 urad. Subsequently, our antenna establishes an uplink to the quantum satellite, Micius, with a link loss of 41-52 dB over a distance of 500-1,400 km. The results clearly confirm the validity of our model, and provide the ability to conduct quantum communications. Our approach can be adopted in various free space optical communication systems between moving platforms. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1912.06317v1-abstract-full').style.display = 'none'; document.getElementById('1912.06317v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 December, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">12 pages, 7 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Opt. Express 26(13), 17044-17055 (2018) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1911.12536">arXiv:1911.12536</a> <span> [<a href="https://arxiv.org/pdf/1911.12536">pdf</a>, <a href="https://arxiv.org/format/1911.12536">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41534-020-00329-3">10.1038/s41534-020-00329-3 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Verification of a resetting protocol for an uncontrolled superconducting qubit </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Gong%2C+M">Ming Gong</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+F">Feihu Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zheng-Da Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zizhu Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Y">Yu-Zhe Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yulin Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shaowei Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+Y">Youwei Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+S">Shiyu Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zha%2C+C">Chen Zha</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+H">Hui Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Yan%2C+Z">Zhiguang Yan</a>, <a href="/search/quant-ph?searchtype=author&query=Rong%2C+H">Hao Rong</a>, <a href="/search/quant-ph?searchtype=author&query=Liang%2C+F">Futian Liang</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+J">Jin Lin</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+Y">Yu Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+C">Cheng Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Sun%2C+L">Lihua Sun</a>, <a href="/search/quant-ph?searchtype=author&query=Castellano%2C+A+D">Anthony D. Castellano</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Chengzhi Peng</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Y">Yu-Ao Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+X">Xiaobo Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Pan%2C+J">Jian-Wei Pan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1911.12536v2-abstract-short" style="display: inline;"> Quantum resetting protocols allow a quantum system to be sent to a state in the past by making it interact with quantum probes when neither the free evolution of the system nor the interaction is controlled. We experimentally verify the simplest non-trivial case of a quantum resetting protocol, known as the $\mathcal{W}_4$ protocol, with five superconducting qubits, testing it with different types… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1911.12536v2-abstract-full').style.display = 'inline'; document.getElementById('1911.12536v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1911.12536v2-abstract-full" style="display: none;"> Quantum resetting protocols allow a quantum system to be sent to a state in the past by making it interact with quantum probes when neither the free evolution of the system nor the interaction is controlled. We experimentally verify the simplest non-trivial case of a quantum resetting protocol, known as the $\mathcal{W}_4$ protocol, with five superconducting qubits, testing it with different types of free evolutions and target-probe interactions. After projection, we obtained a reset state fidelity as high as $0.951$, and the process fidelity was found to be $0.792$. We also implemented 100 randomly-chosen interactions and demonstrated an average success probability of $0.323$ for $|1\rangle$ and $0.292$ for $|-\rangle$, experimentally confirmed the nonzero probability of success for unknown interactions; the numerical simulated values are about $0.3$. Our experiment shows that the simplest quantum resetting protocol can be implemented with current technologies, making such protocols a valuable tool in the eternal fight against unwanted evolution in quantum systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1911.12536v2-abstract-full').style.display = 'none'; document.getElementById('1911.12536v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 December, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 28 November, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">9 pages, 6 figures, 1 table + Supplementary Materials</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> npj Quantum Information 6, 99 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1911.00690">arXiv:1911.00690</a> <span> [<a href="https://arxiv.org/pdf/1911.00690">pdf</a>, <a href="https://arxiv.org/format/1911.00690">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevX.10.031030">10.1103/PhysRevX.10.031030 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> High-speed measurement-device-independent quantum key distribution with integrated silicon photonics </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wei%2C+K">Kejin Wei</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+W">Wei Li</a>, <a href="/search/quant-ph?searchtype=author&query=Tan%2C+H">Hao Tan</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Min%2C+H">Hao Min</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+W">Wei-Jun Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+H">Hao Li</a>, <a href="/search/quant-ph?searchtype=author&query=You%2C+L">Lixing You</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zhen Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Jiang%2C+X">Xiao Jiang</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+T">Teng-Yun Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Liao%2C+S">Sheng-Kai Liao</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Cheng-Zhi Peng</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+F">Feihu Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Pan%2C+J">Jian-Wei Pan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1911.00690v1-abstract-short" style="display: inline;"> Measurement-device-independent quantum key distribution (MDI-QKD) removes all detector side channels and enables secure QKD with an untrusted relay. It is suitable for building a star-type quantum access network, where the complicated and expensive measurement devices are placed in the central untrusted relay and each user requires only a low-cost transmitter, such as an integrated photonic chip.… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1911.00690v1-abstract-full').style.display = 'inline'; document.getElementById('1911.00690v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1911.00690v1-abstract-full" style="display: none;"> Measurement-device-independent quantum key distribution (MDI-QKD) removes all detector side channels and enables secure QKD with an untrusted relay. It is suitable for building a star-type quantum access network, where the complicated and expensive measurement devices are placed in the central untrusted relay and each user requires only a low-cost transmitter, such as an integrated photonic chip. Here, we experimentally demonstrate a 1.25 GHz silicon photonic chip-based MDI-QKD system using polarization encoding. The photonic chip transmitters integrate the necessary encoding components for a standard QKD source. We implement random modulations of polarization states and decoy intensities, and demonstrate a finite-key secret rate of 31 bps over 36 dB channel loss (or 180 km standard fiber). This key rate is higher than state-of-the-art MDI-QKD experiments. The results show that silicon photonic chip-based MDI-QKD, benefiting from miniaturization, low-cost manufacture and compatibility with CMOS microelectronics, is a promising solution for future quantum secure networks. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1911.00690v1-abstract-full').style.display = 'none'; document.getElementById('1911.00690v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 2 November, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">30 pages, 12 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. X 10, 031030 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1908.01271">arXiv:1908.01271</a> <span> [<a href="https://arxiv.org/pdf/1908.01271">pdf</a>, <a href="https://arxiv.org/format/1908.01271">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41566-020-0599-8">10.1038/s41566-020-0599-8 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Surpassing the rate-transmittance linear bound of quantum key distribution </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Fang%2C+X">Xiao-Tian Fang</a>, <a href="/search/quant-ph?searchtype=author&query=Zeng%2C+P">Pei Zeng</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+H">Hui Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Zou%2C+M">Mi Zou</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+W">Weijie Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Tang%2C+Y">Yan-Lin Tang</a>, <a href="/search/quant-ph?searchtype=author&query=Sheng%2C+Y">Ying-Jie Sheng</a>, <a href="/search/quant-ph?searchtype=author&query=Xiang%2C+Y">Yao Xiang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+W">Weijun Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+H">Hao Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zhen Wang</a>, <a href="/search/quant-ph?searchtype=author&query=You%2C+L">Lixing You</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+M">Ming-Jun Li</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+H">Hao Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Y">Yu-Ao Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Q">Qiang Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+C">Cheng-Zhi Peng</a>, <a href="/search/quant-ph?searchtype=author&query=Ma%2C+X">Xiongfeng Ma</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+T">Teng-Yun Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Pan%2C+J">Jian-Wei Pan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1908.01271v1-abstract-short" style="display: inline;"> Quantum key distribution (QKD offers a long-term solution to establish information-theoretically secure keys between two distant users. In practice, with a careful characterization of quantum sources and the decoy-state method, measure-device-independent quantum key distribution (MDI-QKD) provides secure key distribution. While short-distance fibre-based QKD has already been available for real-lif… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1908.01271v1-abstract-full').style.display = 'inline'; document.getElementById('1908.01271v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1908.01271v1-abstract-full" style="display: none;"> Quantum key distribution (QKD offers a long-term solution to establish information-theoretically secure keys between two distant users. In practice, with a careful characterization of quantum sources and the decoy-state method, measure-device-independent quantum key distribution (MDI-QKD) provides secure key distribution. While short-distance fibre-based QKD has already been available for real-life implementation, the bottleneck of practical QKD lies on the limited transmission distance. Due to photon losses in transmission, it was believed that the key generation rate is bounded by a linear function of the channel transmittance, $O(畏)$, without a quantum repeater, which puts an upper bound on the maximal secure transmission distance. Interestingly, a new phase-encoding MDI-QKD scheme, named twin-field QKD, has been suggested to beat the linear bound, while another variant, named phase-matching quantum key distribution (PM-QKD), has been proven to have a quadratic key-rate improvement, $O(\sqrt畏)$. In reality, however, the intrinsic optical mode mismatch of independent lasers, accompanied by phase fluctuation and drift, impedes the successful experimental implementation of the new schemes. Here, we solve this problem with the assistance of the laser injection technique and the phase post-compensation method. In the experiment, the key rate surpasses the linear key-rate bound via 302 km and 402 km commercial-fibre channels, achieving a key rate over 4 orders of magnitude higher than the existing results in literature. Furthermore, with a 502 km ultralow-loss fibre, our system yields a secret key rate of 0.118 bps. We expect this new type of QKD schemes to become a new standard for future QKD. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1908.01271v1-abstract-full').style.display = 'none'; document.getElementById('1908.01271v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 August, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">16 pages, 7 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Photonics, vol. 14, p. 422425, (2020) </p> </li> </ol> <nav class="pagination is-small is-centered breathe-horizontal" role="navigation" aria-label="pagination"> <a 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