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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=Guo%2C+Q&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Guo%2C+Q&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=Guo%2C+Q&start=50" class="pagination-link " aria-label="Page 2" aria-current="page">2 </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/2502.20794">arXiv:2502.20794</a> <span> [<a href="https://arxiv.org/pdf/2502.20794">pdf</a>, <a href="https://arxiv.org/format/2502.20794">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="Atomic Physics">physics.atom-ph</span> </div> </div> <p class="title is-5 mathjax"> Enhancing the coherence time of a neutral atom by an optical quartic trap </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chang%2C+H">Haobo Chang</a>, <a href="/search/quant-ph?searchtype=author&query=Tian%2C+Z">Zhuangzhuang Tian</a>, <a href="/search/quant-ph?searchtype=author&query=Lv%2C+X">Xin Lv</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+M">Mengna Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zhihui Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Q">Qi Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+P">Pengfei Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+P">Pengfei Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+G">Gang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+T">Tiancai Zhang</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="2502.20794v1-abstract-short" style="display: inline;"> The coherence time of an optically trapped neutral atom is a crucial parameter for quantum technologies. We found that optical dipole traps with higher-order spatial forms inherently offer lower decoherence rates compared to those with lower-order spatial forms. We formulated the decoherence rate caused by the variance of the differential energy shift and photon jumping rate. Then, we constructed… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.20794v1-abstract-full').style.display = 'inline'; document.getElementById('2502.20794v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2502.20794v1-abstract-full" style="display: none;"> The coherence time of an optically trapped neutral atom is a crucial parameter for quantum technologies. We found that optical dipole traps with higher-order spatial forms inherently offer lower decoherence rates compared to those with lower-order spatial forms. We formulated the decoherence rate caused by the variance of the differential energy shift and photon jumping rate. Then, we constructed blue-detuned harmonic and quartic optical dipole traps, and experimentally investigated the coherence time of a trapped single cesium atom. The experimental results qualitatively verified our theory. Our approach provides a novel method to enhance the coherence time of optically trapped neutral atoms. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.20794v1-abstract-full').style.display = 'none'; document.getElementById('2502.20794v1-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 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">4 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/2501.09079">arXiv:2501.09079</a> <span> [<a href="https://arxiv.org/pdf/2501.09079">pdf</a>, <a href="https://arxiv.org/format/2501.09079">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"> Demonstrating quantum error mitigation on logical qubits </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+A">Aosai Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Xie%2C+H">Haipeng Xie</a>, <a href="/search/quant-ph?searchtype=author&query=Gao%2C+Y">Yu Gao</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+J">Jia-Nan Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Bao%2C+Z">Zehang Bao</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+Z">Zitian Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+J">Jiachen Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+N">Ning Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+C">Chuanyu Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhong%2C+J">Jiarun Zhong</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+S">Shibo Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+K">Ke Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yaozu Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Jin%2C+F">Feitong Jin</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+X">Xuhao Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Zou%2C+Y">Yiren Zou</a>, <a href="/search/quant-ph?searchtype=author&query=Tan%2C+Z">Ziqi Tan</a>, <a href="/search/quant-ph?searchtype=author&query=Cui%2C+Z">Zhengyi Cui</a>, <a href="/search/quant-ph?searchtype=author&query=Shen%2C+F">Fanhao Shen</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+T">Tingting Li</a>, <a href="/search/quant-ph?searchtype=author&query=Han%2C+Y">Yihang Han</a>, <a href="/search/quant-ph?searchtype=author&query=He%2C+Y">Yiyang He</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+G">Gongyu Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Shen%2C+J">Jiayuan Shen</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+H">Han Wang</a> , et al. (10 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="2501.09079v1-abstract-short" style="display: inline;"> A long-standing challenge in quantum computing is developing technologies to overcome the inevitable noise in qubits. To enable meaningful applications in the early stages of fault-tolerant quantum computing, devising methods to suppress post-correction logical failures is becoming increasingly crucial. In this work, we propose and experimentally demonstrate the application of zero-noise extrapola… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.09079v1-abstract-full').style.display = 'inline'; document.getElementById('2501.09079v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.09079v1-abstract-full" style="display: none;"> A long-standing challenge in quantum computing is developing technologies to overcome the inevitable noise in qubits. To enable meaningful applications in the early stages of fault-tolerant quantum computing, devising methods to suppress post-correction logical failures is becoming increasingly crucial. In this work, we propose and experimentally demonstrate the application of zero-noise extrapolation, a practical quantum error mitigation technique, to error correction circuits on state-of-the-art superconducting processors. By amplifying the noise on physical qubits, the circuits yield outcomes that exhibit a predictable dependence on noise strength, following a polynomial function determined by the code distance. This property enables the effective application of polynomial extrapolation to mitigate logical errors. Our experiments demonstrate a universal reduction in logical errors across various quantum circuits, including fault-tolerant circuits of repetition and surface codes. We observe a favorable performance in multi-round error correction circuits, indicating that this method remains effective when the circuit depth increases. These results advance the frontier of quantum error suppression technologies, opening a practical way to achieve reliable quantum computing in the early fault-tolerant era. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.09079v1-abstract-full').style.display = 'none'; document.getElementById('2501.09079v1-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 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2501.04688">arXiv:2501.04688</a> <span> [<a href="https://arxiv.org/pdf/2501.04688">pdf</a>, <a href="https://arxiv.org/format/2501.04688">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="Statistical Mechanics">cond-mat.stat-mech</span> </div> </div> <p class="title is-5 mathjax"> Observation of topological prethermal strong zero modes </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Jin%2C+F">Feitong Jin</a>, <a href="/search/quant-ph?searchtype=author&query=Jiang%2C+S">Si Jiang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+X">Xuhao Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Bao%2C+Z">Zehang Bao</a>, <a href="/search/quant-ph?searchtype=author&query=Shen%2C+F">Fanhao Shen</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+K">Ke Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+Z">Zitian Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+S">Shibo Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+Z">Zixuan Song</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+J">Jiachen Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Tan%2C+Z">Ziqi Tan</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yaozu Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+C">Chuanyu Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Gao%2C+Y">Yu Gao</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+N">Ning Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zou%2C+Y">Yiren Zou</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+A">Aosai Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+T">Tingting Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhong%2C+J">Jiarun Zhong</a>, <a href="/search/quant-ph?searchtype=author&query=Cui%2C+Z">Zhengyi Cui</a>, <a href="/search/quant-ph?searchtype=author&query=Han%2C+Y">Yihang Han</a>, <a href="/search/quant-ph?searchtype=author&query=He%2C+Y">Yiyang He</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+H">Han Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+J">Jianan Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Y">Yanzhe Wang</a> , et al. (20 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="2501.04688v1-abstract-short" style="display: inline;"> Symmetry-protected topological phases cannot be described by any local order parameter and are beyond the conventional symmetry-breaking paradigm for understanding quantum matter. They are characterized by topological boundary states robust against perturbations that respect the protecting symmetry. In a clean system without disorder, these edge modes typically only occur for the ground states of… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.04688v1-abstract-full').style.display = 'inline'; document.getElementById('2501.04688v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.04688v1-abstract-full" style="display: none;"> Symmetry-protected topological phases cannot be described by any local order parameter and are beyond the conventional symmetry-breaking paradigm for understanding quantum matter. They are characterized by topological boundary states robust against perturbations that respect the protecting symmetry. In a clean system without disorder, these edge modes typically only occur for the ground states of systems with a bulk energy gap and would not survive at finite temperatures due to mobile thermal excitations. Here, we report the observation of a distinct type of topological edge modes, which are protected by emergent symmetries and persist even up to infinite temperature, with an array of 100 programmable superconducting qubits. In particular, through digital quantum simulation of the dynamics of a one-dimensional disorder-free "cluster" Hamiltonian, we observe robust long-lived topological edge modes over up to 30 cycles at a wide range of temperatures. By monitoring the propagation of thermal excitations, we show that despite the free mobility of these excitations, their interactions with the edge modes are substantially suppressed in the dimerized regime due to an emergent U(1)$\times$U(1) symmetry, resulting in an unusually prolonged lifetime of the topological edge modes even at infinite temperature. In addition, we exploit these topological edge modes as logical qubits and prepare a logical Bell state, which exhibits persistent coherence in the dimerized and off-resonant regime, despite the system being disorder-free and far from its ground state. Our results establish a viable digital simulation approach to experimentally exploring a variety of finite-temperature topological phases and demonstrate a potential route to construct long-lived robust boundary qubits that survive to infinite temperature in disorder-free systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.04688v1-abstract-full').style.display = 'none'; document.getElementById('2501.04688v1-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 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2501.04679">arXiv:2501.04679</a> <span> [<a href="https://arxiv.org/pdf/2501.04679">pdf</a>, <a href="https://arxiv.org/format/2501.04679">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> </div> </div> <p class="title is-5 mathjax"> Exploring nontrivial topology at quantum criticality in a superconducting processor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Tan%2C+Z">Ziqi Tan</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+K">Ke Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+S">Sheng Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Shen%2C+F">Fanhao Shen</a>, <a href="/search/quant-ph?searchtype=author&query=Jin%2C+F">Feitong Jin</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+X">Xuhao Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Ji%2C+Y">Yujie Ji</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+S">Shibo Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+J">Jiachen Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yaozu Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+C">Chuanyu Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Gao%2C+Y">Yu Gao</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+N">Ning Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zou%2C+Y">Yiren Zou</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+A">Aosai Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+T">Tingting Li</a>, <a href="/search/quant-ph?searchtype=author&query=Bao%2C+Z">Zehang Bao</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+Z">Zitian Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhong%2C+J">Jiarun Zhong</a>, <a href="/search/quant-ph?searchtype=author&query=Cui%2C+Z">Zhengyi Cui</a>, <a href="/search/quant-ph?searchtype=author&query=Han%2C+Y">Yihang Han</a>, <a href="/search/quant-ph?searchtype=author&query=He%2C+Y">Yiyang He</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+H">Han Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+J">Jianan Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Y">Yanzhe Wang</a> , et al. (15 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="2501.04679v1-abstract-short" style="display: inline;"> The discovery of nontrivial topology in quantum critical states has introduced a new paradigm for classifying quantum phase transitions and challenges the conventional belief that topological phases are typically associated with a bulk energy gap. However, realizing and characterizing such topologically nontrivial quantum critical states with large particle numbers remains an outstanding experimen… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.04679v1-abstract-full').style.display = 'inline'; document.getElementById('2501.04679v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.04679v1-abstract-full" style="display: none;"> The discovery of nontrivial topology in quantum critical states has introduced a new paradigm for classifying quantum phase transitions and challenges the conventional belief that topological phases are typically associated with a bulk energy gap. However, realizing and characterizing such topologically nontrivial quantum critical states with large particle numbers remains an outstanding experimental challenge in statistical and condensed matter physics. Programmable quantum processors can directly prepare and manipulate exotic quantum many-body states, offering a powerful path for exploring the physics behind these states. Here, we present an experimental exploration of the critical cluster Ising model by preparing its low-lying critical states on a superconducting processor with up to $100$ qubits. We develop an efficient method to probe the boundary $g$-function based on prepared low-energy states, which allows us to uniquely identify the nontrivial topology of the critical systems under study. Furthermore, by adapting the entanglement Hamiltonian tomography technique, we recognize two-fold topological degeneracy in the entanglement spectrum under periodic boundary condition, experimentally verifying the universal bulk-boundary correspondence in topological critical systems. Our results demonstrate the low-lying critical states as useful quantum resources for investigating the interplay between topology and quantum criticality. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.04679v1-abstract-full').style.display = 'none'; document.getElementById('2501.04679v1-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 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.07997">arXiv:2411.07997</a> <span> [<a href="https://arxiv.org/pdf/2411.07997">pdf</a>, <a href="https://arxiv.org/format/2411.07997">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Gases">cond-mat.quant-gas</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"> Tunneling Spectroscopy in Superconducting Circuit Lattices </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Du%2C+B">Botao Du</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Q">Qihao Guo</a>, <a href="/search/quant-ph?searchtype=author&query=L%C3%B3pez%2C+S">Santiago L贸pez</a>, <a href="/search/quant-ph?searchtype=author&query=Ma%2C+R">Ruichao Ma</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="2411.07997v1-abstract-short" style="display: inline;"> We demonstrate tunneling spectroscopy of synthetic quantum matter in superconducting circuit lattices. We measure site-resolved excitation spectra by coupling the lattice to engineered driven-dissipative particle baths that serve as local tunneling probes. Using incoherent particle source and drain, we independently extract quasi-particle and quasi-hole spectra and reconstruct the spatial structur… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.07997v1-abstract-full').style.display = 'inline'; document.getElementById('2411.07997v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.07997v1-abstract-full" style="display: none;"> We demonstrate tunneling spectroscopy of synthetic quantum matter in superconducting circuit lattices. We measure site-resolved excitation spectra by coupling the lattice to engineered driven-dissipative particle baths that serve as local tunneling probes. Using incoherent particle source and drain, we independently extract quasi-particle and quasi-hole spectra and reconstruct the spatial structure of collective excitations. We perform spectroscopy of a strongly interacting Bose-Hubbard lattice at different densities, observing changes in energy gaps across the superfluid to Mott-insulator transition and the effects of three-body interactions. Our results provide a new toolset for characterizing many-body states in analog quantum simulators. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.07997v1-abstract-full').style.display = 'none'; document.getElementById('2411.07997v1-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 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">8 pages, 4 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/2411.06794">arXiv:2411.06794</a> <span> [<a href="https://arxiv.org/pdf/2411.06794">pdf</a>, <a href="https://arxiv.org/format/2411.06794">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="Statistical Mechanics">cond-mat.stat-mech</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/s41467-024-54332-9">10.1038/s41467-024-54332-9 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Emergence of steady quantum transport in a superconducting processor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+P">Pengfei Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Gao%2C+Y">Yu Gao</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+X">Xiansong Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+N">Ning Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Dong%2C+H">Hang Dong</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+C">Chu Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+J">Jinfeng Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+X">Xu Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+J">Jiachen Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+S">Shibo Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+K">Ke Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yaozu Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+C">Chuanyu Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Jin%2C+F">Feitong Jin</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+X">Xuhao Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+A">Aosai Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Zou%2C+Y">Yiren Zou</a>, <a href="/search/quant-ph?searchtype=author&query=Tan%2C+Z">Ziqi Tan</a>, <a href="/search/quant-ph?searchtype=author&query=Cui%2C+Z">Zhengyi Cui</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+Z">Zitian Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Shen%2C+F">Fanhao Shen</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+T">Tingting Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhong%2C+J">Jiarun Zhong</a>, <a href="/search/quant-ph?searchtype=author&query=Bao%2C+Z">Zehang Bao</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+L">Liangtian Zhao</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="2411.06794v1-abstract-short" style="display: inline;"> Non-equilibrium quantum transport is crucial to technological advances ranging from nanoelectronics to thermal management. In essence, it deals with the coherent transfer of energy and (quasi-)particles through quantum channels between thermodynamic baths. A complete understanding of quantum transport thus requires the ability to simulate and probe macroscopic and microscopic physics on equal foot… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.06794v1-abstract-full').style.display = 'inline'; document.getElementById('2411.06794v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.06794v1-abstract-full" style="display: none;"> Non-equilibrium quantum transport is crucial to technological advances ranging from nanoelectronics to thermal management. In essence, it deals with the coherent transfer of energy and (quasi-)particles through quantum channels between thermodynamic baths. A complete understanding of quantum transport thus requires the ability to simulate and probe macroscopic and microscopic physics on equal footing. Using a superconducting quantum processor, we demonstrate the emergence of non-equilibrium steady quantum transport by emulating the baths with qubit ladders and realising steady particle currents between the baths. We experimentally show that the currents are independent of the microscopic details of bath initialisation, and their temporal fluctuations decrease rapidly with the size of the baths, emulating those predicted by thermodynamic baths. The above characteristics are experimental evidence of pure-state statistical mechanics and prethermalisation in non-equilibrium many-body quantum systems. Furthermore, by utilising precise controls and measurements with single-site resolution, we demonstrate the capability to tune steady currents by manipulating the macroscopic properties of the baths, including filling and spectral properties. Our investigation paves the way for a new generation of experimental exploration of non-equilibrium quantum transport in strongly correlated quantum matter. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.06794v1-abstract-full').style.display = 'none'; document.getElementById('2411.06794v1-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> 11 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">7 pages, 4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nat. Commun. 15, 10115 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.11630">arXiv:2410.11630</a> <span> [<a href="https://arxiv.org/pdf/2410.11630">pdf</a>, <a href="https://arxiv.org/format/2410.11630">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"> Generating entanglement of two acoustic modes by driving the qubit in circuit quantum acoustodynamics system </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wei%2C+M">Mei-Rong Wei</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Q">Qi Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+G">Gang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+T">Tiancai Zhang</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="2410.11630v2-abstract-short" style="display: inline;"> We propose how to generate the entanglement of two long-lived phonon modes in a circuit quantum acoustodynamics system, which consists of a multi-mode high-frequency bulk acoustic wave resonator and a transmon-type superconducting qubit. Two acoustic modes couple to the qubit through piezoelectric interaction, and the qubit is driven by a microwave field. Under the condition of far detuning betwee… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.11630v2-abstract-full').style.display = 'inline'; document.getElementById('2410.11630v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.11630v2-abstract-full" style="display: none;"> We propose how to generate the entanglement of two long-lived phonon modes in a circuit quantum acoustodynamics system, which consists of a multi-mode high-frequency bulk acoustic wave resonator and a transmon-type superconducting qubit. Two acoustic modes couple to the qubit through piezoelectric interaction, and the qubit is driven by a microwave field. Under the condition of far detuning between the qubit and acoustic modes, the qubit can be eliminated adiabatically, and thus establishing the indirect interaction between the two acoustic modes. We demonstrate that such the indirect interaction can be the parametric-amplification-type interaction by appropriately choosing the drive frequency and strength, so the entanglement between acoustic modes can be created by the direct unitary evolution. We numerically analyze the parameter conditions for generating the entanglement in detail and evaluate the influence of system dissipations and noise. The results show that the scheme can be realized using currently available parameters and has strong robustness against the dissipations and environmental temperature. This work may provide efficient resource for the quantum information processing based on the phononic systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.11630v2-abstract-full').style.display = 'none'; document.getElementById('2410.11630v2-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 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 15 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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, 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/2409.09729">arXiv:2409.09729</a> <span> [<a href="https://arxiv.org/pdf/2409.09729">pdf</a>, <a href="https://arxiv.org/format/2409.09729">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 continual learning on a programmable superconducting processor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+C">Chuanyu Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Lu%2C+Z">Zhide Lu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+L">Liangtian Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+S">Shibo Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+W">Weikang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+K">Ke Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+J">Jiachen Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yaozu Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Jin%2C+F">Feitong Jin</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+X">Xuhao Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Gao%2C+Y">Yu Gao</a>, <a href="/search/quant-ph?searchtype=author&query=Tan%2C+Z">Ziqi Tan</a>, <a href="/search/quant-ph?searchtype=author&query=Cui%2C+Z">Zhengyi Cui</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+A">Aosai Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+N">Ning Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zou%2C+Y">Yiren Zou</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+T">Tingting Li</a>, <a href="/search/quant-ph?searchtype=author&query=Shen%2C+F">Fanhao Shen</a>, <a href="/search/quant-ph?searchtype=author&query=Zhong%2C+J">Jiarun Zhong</a>, <a href="/search/quant-ph?searchtype=author&query=Bao%2C+Z">Zehang Bao</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+Z">Zitian Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+Z">Zixuan Song</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+J">Jinfeng Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Dong%2C+H">Hang Dong</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+P">Pengfei Zhang</a> , et al. (10 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="2409.09729v1-abstract-short" style="display: inline;"> Quantum computers may outperform classical computers on machine learning tasks. In recent years, a variety of quantum algorithms promising unparalleled potential to enhance, speed up, or innovate machine learning have been proposed. Yet, quantum learning systems, similar to their classical counterparts, may likewise suffer from the catastrophic forgetting problem, where training a model with new t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.09729v1-abstract-full').style.display = 'inline'; document.getElementById('2409.09729v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.09729v1-abstract-full" style="display: none;"> Quantum computers may outperform classical computers on machine learning tasks. In recent years, a variety of quantum algorithms promising unparalleled potential to enhance, speed up, or innovate machine learning have been proposed. Yet, quantum learning systems, similar to their classical counterparts, may likewise suffer from the catastrophic forgetting problem, where training a model with new tasks would result in a dramatic performance drop for the previously learned ones. This problem is widely believed to be a crucial obstacle to achieving continual learning of multiple sequential tasks. Here, we report an experimental demonstration of quantum continual learning on a fully programmable superconducting processor. In particular, we sequentially train a quantum classifier with three tasks, two about identifying real-life images and the other on classifying quantum states, and demonstrate its catastrophic forgetting through experimentally observed rapid performance drops for prior tasks. To overcome this dilemma, we exploit the elastic weight consolidation strategy and show that the quantum classifier can incrementally learn and retain knowledge across the three distinct tasks, with an average prediction accuracy exceeding 92.3%. In addition, for sequential tasks involving quantum-engineered data, we demonstrate that the quantum classifier can achieve a better continual learning performance than a commonly used classical feedforward network with a comparable number of variational parameters. Our results establish a viable strategy for empowering quantum learning systems with desirable adaptability to multiple sequential tasks, marking an important primary experimental step towards the long-term goal of achieving quantum artificial general intelligence. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.09729v1-abstract-full').style.display = 'none'; document.getElementById('2409.09729v1-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 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 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, 14 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/2408.11900">arXiv:2408.11900</a> <span> [<a href="https://arxiv.org/pdf/2408.11900">pdf</a>, <a href="https://arxiv.org/format/2408.11900">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="Superconductivity">cond-mat.supr-con</span> </div> </div> <p class="title is-5 mathjax"> Quantum highway: Observation of minimal and maximal speed limits for few and many-body states </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+Z">Zitian Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Gao%2C+L">Lei Gao</a>, <a href="/search/quant-ph?searchtype=author&query=Bao%2C+Z">Zehang Bao</a>, <a href="/search/quant-ph?searchtype=author&query=Xiang%2C+L">Liang Xiang</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+Z">Zixuan Song</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+S">Shibo Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+K">Ke Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+J">Jiachen Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Jin%2C+F">Feitong Jin</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+X">Xuhao Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Gao%2C+Y">Yu Gao</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yaozu Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+C">Chuanyu Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+N">Ning Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zou%2C+Y">Yiren Zou</a>, <a href="/search/quant-ph?searchtype=author&query=Tan%2C+Z">Ziqi Tan</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+A">Aosai Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Cui%2C+Z">Zhengyi Cui</a>, <a href="/search/quant-ph?searchtype=author&query=Shen%2C+F">Fanhao Shen</a>, <a href="/search/quant-ph?searchtype=author&query=Zhong%2C+J">Jiarun Zhong</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+T">Tingting Li</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+J">Jinfeng Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+X">Xu Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Dong%2C+H">Hang Dong</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+P">Pengfei Zhang</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="2408.11900v1-abstract-short" style="display: inline;"> Tracking the time evolution of a quantum state allows one to verify the thermalization rate or the propagation speed of correlations in generic quantum systems. Inspired by the energy-time uncertainty principle, bounds have been demonstrated on the maximal speed at which a quantum state can change, resulting in immediate and practical tasks. Based on a programmable superconducting quantum processo… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.11900v1-abstract-full').style.display = 'inline'; document.getElementById('2408.11900v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.11900v1-abstract-full" style="display: none;"> Tracking the time evolution of a quantum state allows one to verify the thermalization rate or the propagation speed of correlations in generic quantum systems. Inspired by the energy-time uncertainty principle, bounds have been demonstrated on the maximal speed at which a quantum state can change, resulting in immediate and practical tasks. Based on a programmable superconducting quantum processor, we test the dynamics of various emulated quantum mechanical systems encompassing single- and many-body states. We show that one can test the known quantum speed limits and that modifying a single Hamiltonian parameter allows the observation of the crossover of the different bounds on the dynamics. We also unveil the observation of minimal quantum speed limits in addition to more common maximal ones, i.e., the lowest rate of change of a unitarily evolved quantum state. Our results establish a comprehensive experimental characterization of quantum speed limits and pave the way for their subsequent study in engineered non-unitary conditions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.11900v1-abstract-full').style.display = 'none'; document.getElementById('2408.11900v1-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 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">9 pages,4 figures + supplementary information</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.12347">arXiv:2407.12347</a> <span> [<a href="https://arxiv.org/pdf/2407.12347">pdf</a>, <a href="https://arxiv.org/format/2407.12347">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"> Improved Nonlocality Certification via Bouncing between Bell Operators and Inequalities </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+W">Weikang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Hu%2C+M">Mengyao Hu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+K">Ke Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+S">Shibo Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Lu%2C+Z">Zhide Lu</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+J">Jiachen Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yaozu Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+C">Chuanyu Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Jin%2C+F">Feitong Jin</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+X">Xuhao Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Gao%2C+Y">Yu Gao</a>, <a href="/search/quant-ph?searchtype=author&query=Cui%2C+Z">Zhengyi Cui</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+A">Aosai Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+N">Ning Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zou%2C+Y">Yiren Zou</a>, <a href="/search/quant-ph?searchtype=author&query=Shen%2C+F">Fanhao Shen</a>, <a href="/search/quant-ph?searchtype=author&query=Zhong%2C+J">Jiarun Zhong</a>, <a href="/search/quant-ph?searchtype=author&query=Bao%2C+Z">Zehang Bao</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+Z">Zitian Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+P">Pengfei Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+H">Hekang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Q">Qiujiang Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zhen Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+D">Dong-Ling Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+C">Chao Song</a> , et al. (3 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="2407.12347v1-abstract-short" style="display: inline;"> Bell nonlocality is an intrinsic feature of quantum mechanics, which can be certified via the violation of Bell inequalities. It is therefore a fundamental question to certify Bell nonlocality from experimental data. Here, we present an optimization scheme to improve nonlocality certification by exploring flexible mappings between Bell inequalities and Hamiltonians corresponding to the Bell operat… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.12347v1-abstract-full').style.display = 'inline'; document.getElementById('2407.12347v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.12347v1-abstract-full" style="display: none;"> Bell nonlocality is an intrinsic feature of quantum mechanics, which can be certified via the violation of Bell inequalities. It is therefore a fundamental question to certify Bell nonlocality from experimental data. Here, we present an optimization scheme to improve nonlocality certification by exploring flexible mappings between Bell inequalities and Hamiltonians corresponding to the Bell operators. We show that several Hamiltonian models can be mapped to new inequalities with improved classical bounds than the original one, enabling a more robust detection of nonlocality. From the other direction, we investigate the mapping from fixed Bell inequalities to Hamiltonians, aiming to maximize quantum violations while considering experimental imperfections. As a practical demonstration, we apply this method to an XXZ-like honeycomb-lattice model utilizing over 70 superconducting qubits. The successful application of this technique, as well as combining the two directions to form an optimization loop, may open new avenues for developing more practical and noise-resilient nonlocality certification techniques and enable broader experimental explorations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.12347v1-abstract-full').style.display = 'none'; document.getElementById('2407.12347v1-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 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">11 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/2406.17841">arXiv:2406.17841</a> <span> [<a href="https://arxiv.org/pdf/2406.17841">pdf</a>, <a href="https://arxiv.org/format/2406.17841">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="Artificial Intelligence">cs.AI</span> </div> </div> <p class="title is-5 mathjax"> Probing many-body Bell correlation depth with superconducting qubits </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wang%2C+K">Ke Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+W">Weikang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+S">Shibo Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Hu%2C+M">Mengyao Hu</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+J">Jiachen Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yaozu Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+C">Chuanyu Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Jin%2C+F">Feitong Jin</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+X">Xuhao Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Gao%2C+Y">Yu Gao</a>, <a href="/search/quant-ph?searchtype=author&query=Tan%2C+Z">Ziqi Tan</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+A">Aosai Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+N">Ning Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zou%2C+Y">Yiren Zou</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+T">Tingting Li</a>, <a href="/search/quant-ph?searchtype=author&query=Shen%2C+F">Fanhao Shen</a>, <a href="/search/quant-ph?searchtype=author&query=Zhong%2C+J">Jiarun Zhong</a>, <a href="/search/quant-ph?searchtype=author&query=Bao%2C+Z">Zehang Bao</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+Z">Zitian Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+Z">Zixuan Song</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+J">Jinfeng Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Dong%2C+H">Hang Dong</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+X">Xu Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+P">Pengfei Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Jiang%2C+W">Wenjie Jiang</a> , et al. (10 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="2406.17841v1-abstract-short" style="display: inline;"> Quantum nonlocality describes a stronger form of quantum correlation than that of entanglement. It refutes Einstein's belief of local realism and is among the most distinctive and enigmatic features of quantum mechanics. It is a crucial resource for achieving quantum advantages in a variety of practical applications, ranging from cryptography and certified random number generation via self-testing… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.17841v1-abstract-full').style.display = 'inline'; document.getElementById('2406.17841v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2406.17841v1-abstract-full" style="display: none;"> Quantum nonlocality describes a stronger form of quantum correlation than that of entanglement. It refutes Einstein's belief of local realism and is among the most distinctive and enigmatic features of quantum mechanics. It is a crucial resource for achieving quantum advantages in a variety of practical applications, ranging from cryptography and certified random number generation via self-testing to machine learning. Nevertheless, the detection of nonlocality, especially in quantum many-body systems, is notoriously challenging. Here, we report an experimental certification of genuine multipartite Bell correlations, which signal nonlocality in quantum many-body systems, up to 24 qubits with a fully programmable superconducting quantum processor. In particular, we employ energy as a Bell correlation witness and variationally decrease the energy of a many-body system across a hierarchy of thresholds, below which an increasing Bell correlation depth can be certified from experimental data. As an illustrating example, we variationally prepare the low-energy state of a two-dimensional honeycomb model with 73 qubits and certify its Bell correlations by measuring an energy that surpasses the corresponding classical bound with up to 48 standard deviations. In addition, we variationally prepare a sequence of low-energy states and certify their genuine multipartite Bell correlations up to 24 qubits via energies measured efficiently by parity oscillation and multiple quantum coherence techniques. Our results establish a viable approach for preparing and certifying multipartite Bell correlations, which provide not only a finer benchmark beyond entanglement for quantum devices, but also a valuable guide towards exploiting multipartite Bell correlation in a wide spectrum of practical applications. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.17841v1-abstract-full').style.display = 'none'; document.getElementById('2406.17841v1-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> 25 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">11 pages,6 figures + 14 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/2406.00862">arXiv:2406.00862</a> <span> [<a href="https://arxiv.org/pdf/2406.00862">pdf</a>, <a href="https://arxiv.org/format/2406.00862">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="Distributed, Parallel, and Cluster Computing">cs.DC</span> </div> </div> <p class="title is-5 mathjax"> Quantum Computing in Intelligent Transportation Systems: A Survey </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhuang%2C+Y">Yifan Zhuang</a>, <a href="/search/quant-ph?searchtype=author&query=Azfar%2C+T">Talha Azfar</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Y">Yinhai Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Sun%2C+W">Wei Sun</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+X+C">Xiaokun Cara Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Q+V">Qianwen Vivian Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Ke%2C+R">Ruimin Ke</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="2406.00862v2-abstract-short" style="display: inline;"> Quantum computing, a field utilizing the principles of quantum mechanics, promises great advancements across various industries. This survey paper is focused on the burgeoning intersection of quantum computing and intelligent transportation systems, exploring its potential to transform areas such as traffic optimization, logistics, routing, and autonomous vehicles. By examining current research ef… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.00862v2-abstract-full').style.display = 'inline'; document.getElementById('2406.00862v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2406.00862v2-abstract-full" style="display: none;"> Quantum computing, a field utilizing the principles of quantum mechanics, promises great advancements across various industries. This survey paper is focused on the burgeoning intersection of quantum computing and intelligent transportation systems, exploring its potential to transform areas such as traffic optimization, logistics, routing, and autonomous vehicles. By examining current research efforts, challenges, and future directions, this survey aims to provide a comprehensive overview of how quantum computing could affect the future of transportation. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.00862v2-abstract-full').style.display = 'none'; document.getElementById('2406.00862v2-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> 3 June, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 2 June, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2405.19564">arXiv:2405.19564</a> <span> [<a href="https://arxiv.org/pdf/2405.19564">pdf</a>, <a href="https://arxiv.org/ps/2405.19564">ps</a>, <a href="https://arxiv.org/format/2405.19564">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"> Parity-controlled gate in a two-dimensional neutral-atom array </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Guo%2C+F+Q">F. Q. Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Su%2C+S+L">S. L. Su</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+W">Weibin Li</a>, <a href="/search/quant-ph?searchtype=author&query=Shao%2C+X+Q">X. Q. Shao</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="2405.19564v2-abstract-short" style="display: inline;"> We propose a parity-controlled gate within a two-dimensional Rydberg atom array, enabling efficient discrimination between even and odd parities of virtually excited control atoms by monitoring the dynamic evolution of an auxiliary atom. This is achieved through the use of spin-exchange dipolar interactions between Rydberg states and coupling between ground states and Rydberg states. For practical… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.19564v2-abstract-full').style.display = 'inline'; document.getElementById('2405.19564v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.19564v2-abstract-full" style="display: none;"> We propose a parity-controlled gate within a two-dimensional Rydberg atom array, enabling efficient discrimination between even and odd parities of virtually excited control atoms by monitoring the dynamic evolution of an auxiliary atom. This is achieved through the use of spin-exchange dipolar interactions between Rydberg states and coupling between ground states and Rydberg states. For practical applications, we explore its implementation in three-qubit repetition codes and rotated surface codes featuring $XZZX$ stabilizers, enabling single-shot readout of stabilizer measurements. Comprehensive numerical simulations are conducted to assess the feasibility of the proposed approach, taking into account potential experimental imperfections such as unwanted interactions between Rydberg states, atomic position fluctuations, laser phase noise, and Rabi amplitude noise. Our study highlights the inherent advantages of the physical mechanisms underlying parity measurement, demonstrating its reliability and practicality. These findings establish our protocol as a highly promising solution for quantum error detection and computation within Rydberg atom systems, with significant potential for future experimental realizations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.19564v2-abstract-full').style.display = 'none'; document.getElementById('2405.19564v2-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 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 29 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 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">title changed, accepted by PRA</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2405.06853">arXiv:2405.06853</a> <span> [<a href="https://arxiv.org/pdf/2405.06853">pdf</a>, <a href="https://arxiv.org/format/2405.06853">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="Other Condensed Matter">cond-mat.other</span> </div> </div> <p class="title is-5 mathjax"> Quantum State Transfer in Interacting, Multiple-Excitation Systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Yue%2C+A">Alexander Yue</a>, <a href="/search/quant-ph?searchtype=author&query=Mondaini%2C+R">Rubem Mondaini</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Q">Qiujiang Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Scalettar%2C+R+T">Richard T. Scalettar</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="2405.06853v2-abstract-short" style="display: inline;"> Quantum state transfer (QST) describes the coherent passage of quantum information from one node in a network to another. Experiments on QST span a diverse set of platforms and currently report transport across up to tens of nodes in times of several hundred nanoseconds with fidelities that can approach 90% or more. Theoretical studies examine both the lossless time evolution associated with a giv… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.06853v2-abstract-full').style.display = 'inline'; document.getElementById('2405.06853v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.06853v2-abstract-full" style="display: none;"> Quantum state transfer (QST) describes the coherent passage of quantum information from one node in a network to another. Experiments on QST span a diverse set of platforms and currently report transport across up to tens of nodes in times of several hundred nanoseconds with fidelities that can approach 90% or more. Theoretical studies examine both the lossless time evolution associated with a given (Hermitian) lattice Hamiltonian and methods based on the master equation that allows for losses. In this paper, we describe Monte Carlo techniques which enable the discovery of a Hamiltonian that gives high-fidelity QST. We benchmark our approach in geometries appropriate to coupled optical cavity-emitter arrays and discuss connections to condensed matter Hamiltonians of localized orbitals coupled to conduction bands. The resulting Jaynes-Cummings-Hubbard and periodic Anderson models can, in principle, be engineered in appropriate hardware to give efficient QST. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.06853v2-abstract-full').style.display = 'none'; document.getElementById('2405.06853v2-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 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 10 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 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">12 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/2404.15878">arXiv:2404.15878</a> <span> [<a href="https://arxiv.org/pdf/2404.15878">pdf</a>, <a href="https://arxiv.org/format/2404.15878">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="Fluid Dynamics">physics.flu-dyn</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/s42005-024-01845-w">10.1038/s42005-024-01845-w <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Simulating unsteady fluid flows on a superconducting quantum processor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Meng%2C+Z">Zhaoyuan Meng</a>, <a href="/search/quant-ph?searchtype=author&query=Zhong%2C+J">Jiarun Zhong</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+S">Shibo Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+K">Ke Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+J">Jiachen Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Jin%2C+F">Feitong Jin</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+X">Xuhao Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Gao%2C+Y">Yu Gao</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yaozu Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+C">Chuanyu Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+N">Ning Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zou%2C+Y">Yiren Zou</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+A">Aosai Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Cui%2C+Z">Zhengyi Cui</a>, <a href="/search/quant-ph?searchtype=author&query=Shen%2C+F">Fanhao Shen</a>, <a href="/search/quant-ph?searchtype=author&query=Bao%2C+Z">Zehang Bao</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+Z">Zitian Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Tan%2C+Z">Ziqi Tan</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+T">Tingting Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+P">Pengfei Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Xiong%2C+S">Shiying Xiong</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+H">Hekang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Q">Qiujiang Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zhen Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+C">Chao Song</a> , et al. (2 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="2404.15878v1-abstract-short" style="display: inline;"> Recent advancements of intermediate-scale quantum processors have triggered tremendous interest in the exploration of practical quantum advantage. The simulation of fluid dynamics, a highly challenging problem in classical physics but vital for practical applications, emerges as a good candidate for showing quantum utility. Here, we report an experiment on the digital simulation of unsteady flows,… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.15878v1-abstract-full').style.display = 'inline'; document.getElementById('2404.15878v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2404.15878v1-abstract-full" style="display: none;"> Recent advancements of intermediate-scale quantum processors have triggered tremendous interest in the exploration of practical quantum advantage. The simulation of fluid dynamics, a highly challenging problem in classical physics but vital for practical applications, emerges as a good candidate for showing quantum utility. Here, we report an experiment on the digital simulation of unsteady flows, which consists of quantum encoding, evolution, and detection of flow states, with a superconducting quantum processor. The quantum algorithm is based on the Hamiltonian simulation using the hydrodynamic formulation of the Schr枚dinger equation. With the median fidelities of 99.97% and 99.67% for parallel single- and two-qubit gates respectively, we simulate the dynamics of a two-dimensional (2D) compressible diverging flow and a 2D decaying vortex with ten qubits. The experimental results well capture the temporal evolution of averaged density and momentum profiles, and qualitatively reproduce spatial flow fields with moderate noises. This work demonstrates the potential of quantum computing in simulating more complex flows, such as turbulence, for practical applications. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.15878v1-abstract-full').style.display = 'none'; document.getElementById('2404.15878v1-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> 24 April, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2404.00091">arXiv:2404.00091</a> <span> [<a href="https://arxiv.org/pdf/2404.00091">pdf</a>, <a href="https://arxiv.org/format/2404.00091">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/s41567-024-02529-6">10.1038/s41567-024-02529-6 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Non-Abelian braiding of Fibonacci anyons with a superconducting processor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Xu%2C+S">Shibo Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Sun%2C+Z">Zheng-Zhi Sun</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+K">Ke Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+H">Hekang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+Z">Zitian Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Dong%2C+H">Hang Dong</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+J">Jinfeng Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+X">Xu Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+J">Jiachen Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yaozu Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+C">Chuanyu Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Jin%2C+F">Feitong Jin</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+X">Xuhao Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Gao%2C+Y">Yu Gao</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+A">Aosai Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+N">Ning Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zou%2C+Y">Yiren Zou</a>, <a href="/search/quant-ph?searchtype=author&query=Tan%2C+Z">Ziqi Tan</a>, <a href="/search/quant-ph?searchtype=author&query=Shen%2C+F">Fanhao Shen</a>, <a href="/search/quant-ph?searchtype=author&query=Zhong%2C+J">Jiarun Zhong</a>, <a href="/search/quant-ph?searchtype=author&query=Bao%2C+Z">Zehang Bao</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+W">Weikang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Jiang%2C+W">Wenjie Jiang</a>, <a href="/search/quant-ph?searchtype=author&query=Yu%2C+L">Li-Wei Yu</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+Z">Zixuan Song</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="2404.00091v1-abstract-short" style="display: inline;"> Non-Abelian topological orders offer an intriguing path towards fault-tolerant quantum computation, where information can be encoded and manipulated in a topologically protected manner immune to arbitrary local noises and perturbations. However, realizing non-Abelian topologically ordered states is notoriously challenging in both condensed matter and programmable quantum systems, and it was not un… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.00091v1-abstract-full').style.display = 'inline'; document.getElementById('2404.00091v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2404.00091v1-abstract-full" style="display: none;"> Non-Abelian topological orders offer an intriguing path towards fault-tolerant quantum computation, where information can be encoded and manipulated in a topologically protected manner immune to arbitrary local noises and perturbations. However, realizing non-Abelian topologically ordered states is notoriously challenging in both condensed matter and programmable quantum systems, and it was not until recently that signatures of non-Abelian statistics were observed through digital quantum simulation approaches. Despite these exciting progresses, none of them has demonstrated the appropriate type of topological orders and associated non-Abelian anyons whose braidings alone support universal quantum computation. Here, we report the realization of non-Abelian topologically ordered states of the Fibonacci string-net model and demonstrate braidings of Fibonacci anyons featuring universal computational power, with a superconducting quantum processor. We exploit efficient quantum circuits to prepare the desired states and verify their nontrivial topological nature by measuring the topological entanglement entropy. In addition, we create two pairs of Fibonacci anyons and demonstrate their fusion rule and non-Abelian braiding statistics by applying unitary gates on the underlying physical qubits. Our results establish a versatile digital approach to exploring exotic non-Abelian topological states and their associated braiding statistics with current noisy intermediate-scale quantum processors. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.00091v1-abstract-full').style.display = 'none'; document.getElementById('2404.00091v1-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 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.16935">arXiv:2403.16935</a> <span> [<a href="https://arxiv.org/pdf/2403.16935">pdf</a>, <a href="https://arxiv.org/format/2403.16935">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.134.010402">10.1103/PhysRevLett.134.010402 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Measuring Spectral Form Factor in Many-Body Chaotic and Localized Phases of Quantum Processors </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Dong%2C+H">Hang Dong</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+P">Pengfei Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Dag%2C+C+B">Ceren B. Dag</a>, <a href="/search/quant-ph?searchtype=author&query=Gao%2C+Y">Yu Gao</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+N">Ning Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+J">Jinfeng Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+X">Xu Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+J">Jiachen Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+S">Shibo Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+K">Ke Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yaozu Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+C">Chuanyu Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Jin%2C+F">Feitong Jin</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+X">Xuhao Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+A">Aosai Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Zou%2C+Y">Yiren Zou</a>, <a href="/search/quant-ph?searchtype=author&query=Tan%2C+Z">Ziqi Tan</a>, <a href="/search/quant-ph?searchtype=author&query=Cui%2C+Z">Zhengyi Cui</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+Z">Zitian Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Shen%2C+F">Fanhao Shen</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+T">Tingting Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhong%2C+J">Jiarun Zhong</a>, <a href="/search/quant-ph?searchtype=author&query=Bao%2C+Z">Zehang Bao</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+H">Hekang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zhen Wang</a> , et al. (6 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="2403.16935v1-abstract-short" style="display: inline;"> The spectral form factor (SFF) captures universal spectral fluctuations as signatures of quantum chaos, and has been instrumental in advancing multiple frontiers of physics including the studies of black holes and quantum many-body systems. However, the measurement of SFF in many-body systems is challenging due to the difficulty in resolving level spacings that become exponentially small with incr… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.16935v1-abstract-full').style.display = 'inline'; document.getElementById('2403.16935v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.16935v1-abstract-full" style="display: none;"> The spectral form factor (SFF) captures universal spectral fluctuations as signatures of quantum chaos, and has been instrumental in advancing multiple frontiers of physics including the studies of black holes and quantum many-body systems. However, the measurement of SFF in many-body systems is challenging due to the difficulty in resolving level spacings that become exponentially small with increasing system size. Here we experimentally measure the SFF to probe the presence or absence of chaos in quantum many-body systems using a superconducting quantum processor with a randomized measurement protocol. For a Floquet chaotic system, we observe signatures of spectral rigidity of random matrix theory in SFF given by the ramp-plateau behavior. For a Hamiltonian system, we utilize SFF to distinguish the quantum many-body chaotic phase and the prethermal many-body localization. We observe the dip-ramp-plateau behavior of random matrix theory in the chaotic phase, and contrast the scaling of the plateau time in system size between the many-body chaotic and localized phases. Furthermore, we probe the eigenstate statistics by measuring a generalization of the SFF, known as the partial SFF, and observe distinct behaviors in the purities of the reduced density matrix in the two phases. This work unveils a new way of extracting the universal signatures of many-body quantum chaos in quantum devices by probing the correlations in eigenenergies and eigenstates. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.16935v1-abstract-full').style.display = 'none'; document.getElementById('2403.16935v1-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> 25 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 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">12 pages, 9 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. 134, 010402 (2025) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.03579">arXiv:2403.03579</a> <span> [<a href="https://arxiv.org/pdf/2403.03579">pdf</a>, <a href="https://arxiv.org/format/2403.03579">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"> Testing the unified bounds of quantum speed limit </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yaozu Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Yuan%2C+J">Jiale Yuan</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+C">Chuanyu Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+Z">Zitian Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+J">Jinfeng Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+X">Xu Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+P">Pengfei Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Q">Qiujiang Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zhen Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+J">Jiehui Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+C">Chao Song</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+H">Hekang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+D">Da-Wei Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+H">H. Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Agarwal%2C+G+S">Girish S. Agarwal</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="2403.03579v1-abstract-short" style="display: inline;"> Quantum speed limits (QSLs) impose fundamental constraints on the evolution speed of quantum systems. Traditionally, the Mandelstam-Tamm (MT) and Margolus-Levitin (ML) bounds have been widely employed, relying on the standard deviation and mean of energy distribution to define the QSLs. However, these universal bounds only offer loose restrictions on the quantum evolution. Here we introduce the ge… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.03579v1-abstract-full').style.display = 'inline'; document.getElementById('2403.03579v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.03579v1-abstract-full" style="display: none;"> Quantum speed limits (QSLs) impose fundamental constraints on the evolution speed of quantum systems. Traditionally, the Mandelstam-Tamm (MT) and Margolus-Levitin (ML) bounds have been widely employed, relying on the standard deviation and mean of energy distribution to define the QSLs. However, these universal bounds only offer loose restrictions on the quantum evolution. Here we introduce the generalized ML bounds, which prove to be more stringent in constraining dynamic evolution, by utilizing moments of energy spectra of arbitrary orders, even noninteger orders. To validate our findings, we conduct experiments in a superconducting circuit, where we have the capability to prepare a wide range of quantum photonic states and rigorously test these bounds by measuring the evolution of the system and its photon statistics using quantum state tomography. While, in general, the MT bound is effective for short-time evolution, we identify specific parameter regimes where either the MT or the generalized ML bounds suffice to constrain the entire evolution. Our findings not only establish new criteria for estimating QSLs but also substantially enhance our comprehension of the dynamic evolution of quantum systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.03579v1-abstract-full').style.display = 'none'; document.getElementById('2403.03579v1-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> 6 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2402.00936">arXiv:2402.00936</a> <span> [<a href="https://arxiv.org/pdf/2402.00936">pdf</a>, <a href="https://arxiv.org/format/2402.00936">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="Superconductivity">cond-mat.supr-con</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/s41467-024-48791-3">10.1038/s41467-024-48791-3 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Enhanced quantum state transfer: Circumventing quantum chaotic behavior </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Xiang%2C+L">Liang Xiang</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+J">Jiachen Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+Z">Zitian Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+Z">Zixuan Song</a>, <a href="/search/quant-ph?searchtype=author&query=Bao%2C+Z">Zehang Bao</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+X">Xuhao Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Jin%2C+F">Feitong Jin</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+K">Ke Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+S">Shibo Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Zou%2C+Y">Yiren Zou</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+H">Hekang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zhen Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+C">Chao Song</a>, <a href="/search/quant-ph?searchtype=author&query=Yue%2C+A">Alexander Yue</a>, <a href="/search/quant-ph?searchtype=author&query=Partridge%2C+J">Justine Partridge</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Q">Qiujiang Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Mondaini%2C+R">Rubem Mondaini</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+H">H. Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Scalettar%2C+R+T">Richard T. Scalettar</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="2402.00936v1-abstract-short" style="display: inline;"> The ability to realize high-fidelity quantum communication is one of the many facets required to build generic quantum computing devices. In addition to quantum processing, sensing, and storage, transferring the resulting quantum states demands a careful design that finds no parallel in classical communication. Existing experimental demonstrations of quantum information transfer in solid-state qua… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.00936v1-abstract-full').style.display = 'inline'; document.getElementById('2402.00936v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2402.00936v1-abstract-full" style="display: none;"> The ability to realize high-fidelity quantum communication is one of the many facets required to build generic quantum computing devices. In addition to quantum processing, sensing, and storage, transferring the resulting quantum states demands a careful design that finds no parallel in classical communication. Existing experimental demonstrations of quantum information transfer in solid-state quantum systems are largely confined to small chains with few qubits, often relying upon non-generic schemes. Here, by using a large-scale superconducting quantum circuit featuring thirty-six tunable qubits, accompanied by general optimization procedures deeply rooted in overcoming quantum chaotic behavior, we demonstrate a scalable protocol for transferring few-particle quantum states in a two-dimensional quantum network. These include single-qubit excitation and also two-qubit entangled states, and two excitations for which many-body effects are present. Our approach, combined with the quantum circuit's versatility, paves the way to short-distance quantum communication for connecting distributed quantum processors or registers, even if hampered by inherent imperfections in actual quantum devices. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.00936v1-abstract-full').style.display = 'none'; document.getElementById('2402.00936v1-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 February, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 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">10 pages, 4 figures (main text); 14 pages, 20 figures (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/2401.08284">arXiv:2401.08284</a> <span> [<a href="https://arxiv.org/pdf/2401.08284">pdf</a>, <a href="https://arxiv.org/format/2401.08284">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="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/10.1038/s41467-024-53140-5">10.1038/s41467-024-53140-5 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Creating and controlling global Greenberger-Horne-Zeilinger entanglement on quantum processors </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Bao%2C+Z">Zehang Bao</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+S">Shibo Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+Z">Zixuan Song</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+K">Ke Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Xiang%2C+L">Liang Xiang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+Z">Zitian Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+J">Jiachen Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Jin%2C+F">Feitong Jin</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+X">Xuhao Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Gao%2C+Y">Yu Gao</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yaozu Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+C">Chuanyu Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+N">Ning Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zou%2C+Y">Yiren Zou</a>, <a href="/search/quant-ph?searchtype=author&query=Tan%2C+Z">Ziqi Tan</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+A">Aosai Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Cui%2C+Z">Zhengyi Cui</a>, <a href="/search/quant-ph?searchtype=author&query=Shen%2C+F">Fanhao Shen</a>, <a href="/search/quant-ph?searchtype=author&query=Zhong%2C+J">Jiarun Zhong</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+T">Tingting Li</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+J">Jinfeng Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+X">Xu Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Dong%2C+H">Hang Dong</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+P">Pengfei Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+Y">Yang-Ren Liu</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="2401.08284v2-abstract-short" style="display: inline;"> Greenberger-Horne-Zeilinger (GHZ) states, also known as two-component Schr枚dinger cats, play vital roles in the foundation of quantum physics and, more attractively, in future quantum technologies such as fault-tolerant quantum computation. Enlargement in size and coherent control of GHZ states are both crucial for harnessing entanglement in advanced computational tasks with practical advantages,… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.08284v2-abstract-full').style.display = 'inline'; document.getElementById('2401.08284v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2401.08284v2-abstract-full" style="display: none;"> Greenberger-Horne-Zeilinger (GHZ) states, also known as two-component Schr枚dinger cats, play vital roles in the foundation of quantum physics and, more attractively, in future quantum technologies such as fault-tolerant quantum computation. Enlargement in size and coherent control of GHZ states are both crucial for harnessing entanglement in advanced computational tasks with practical advantages, which unfortunately pose tremendous challenges as GHZ states are vulnerable to noise. Here we propose a general strategy for creating, preserving, and manipulating large-scale GHZ entanglement, and demonstrate a series of experiments underlined by high-fidelity digital quantum circuits. For initialization, we employ a scalable protocol to create genuinely entangled GHZ states with up to 60 qubits, almost doubling the previous size record. For protection, we take a new perspective on discrete time crystals (DTCs), originally for exploring exotic nonequilibrium quantum matters, and embed a GHZ state into the eigenstates of a tailor-made cat scar DTC to extend its lifetime. For manipulation, we switch the DTC eigenstates with in-situ quantum gates to modify the effectiveness of the GHZ protection. Our findings establish a viable path towards coherent operations on large-scale entanglement, and further highlight superconducting processors as a promising platform to explore nonequilibrium quantum matters and emerging applications. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.08284v2-abstract-full').style.display = 'none'; document.getElementById('2401.08284v2-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 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 16 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">7 pages, 4 figures + supplementary information</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nat. Commun. 15, 8823 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2401.04333">arXiv:2401.04333</a> <span> [<a href="https://arxiv.org/pdf/2401.04333">pdf</a>, <a href="https://arxiv.org/format/2401.04333">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="Superconductivity">cond-mat.supr-con</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/s41467-024-53077-9">10.1038/s41467-024-53077-9 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Long-lived topological time-crystalline order on a quantum processor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Xiang%2C+L">Liang Xiang</a>, <a href="/search/quant-ph?searchtype=author&query=Jiang%2C+W">Wenjie Jiang</a>, <a href="/search/quant-ph?searchtype=author&query=Bao%2C+Z">Zehang Bao</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+Z">Zixuan Song</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+S">Shibo Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+K">Ke Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+J">Jiachen Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Jin%2C+F">Feitong Jin</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+X">Xuhao Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+Z">Zitian Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Shen%2C+F">Fanhao Shen</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+N">Ning Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+C">Chuanyu Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yaozu Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Zou%2C+Y">Yiren Zou</a>, <a href="/search/quant-ph?searchtype=author&query=Zhong%2C+J">Jiarun Zhong</a>, <a href="/search/quant-ph?searchtype=author&query=Cui%2C+Z">Zhengyi Cui</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+A">Aosai Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Tan%2C+Z">Ziqi Tan</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+T">Tingting Li</a>, <a href="/search/quant-ph?searchtype=author&query=Gao%2C+Y">Yu Gao</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+J">Jinfeng Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+X">Xu Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Dong%2C+H">Hang Dong</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+P">Pengfei Zhang</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="2401.04333v1-abstract-short" style="display: inline;"> Topologically ordered phases of matter elude Landau's symmetry-breaking theory, featuring a variety of intriguing properties such as long-range entanglement and intrinsic robustness against local perturbations. Their extension to periodically driven systems gives rise to exotic new phenomena that are forbidden in thermal equilibrium. Here, we report the observation of signatures of such a phenomen… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.04333v1-abstract-full').style.display = 'inline'; document.getElementById('2401.04333v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2401.04333v1-abstract-full" style="display: none;"> Topologically ordered phases of matter elude Landau's symmetry-breaking theory, featuring a variety of intriguing properties such as long-range entanglement and intrinsic robustness against local perturbations. Their extension to periodically driven systems gives rise to exotic new phenomena that are forbidden in thermal equilibrium. Here, we report the observation of signatures of such a phenomenon -- a prethermal topologically ordered time crystal -- with programmable superconducting qubits arranged on a square lattice. By periodically driving the superconducting qubits with a surface-code Hamiltonian, we observe discrete time-translation symmetry breaking dynamics that is only manifested in the subharmonic temporal response of nonlocal logical operators. We further connect the observed dynamics to the underlying topological order by measuring a nonzero topological entanglement entropy and studying its subsequent dynamics. Our results demonstrate the potential to explore exotic topologically ordered nonequilibrium phases of matter with noisy intermediate-scale quantum processors. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.04333v1-abstract-full').style.display = 'none'; document.getElementById('2401.04333v1-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 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 (main text), 16 pages (supplementary information)</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2312.10216">arXiv:2312.10216</a> <span> [<a href="https://arxiv.org/pdf/2312.10216">pdf</a>, <a href="https://arxiv.org/format/2312.10216">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/sciadv.adj3822">10.1126/sciadv.adj3822 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Disorder-tunable entanglement at infinite temperature </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Dong%2C+H">Hang Dong</a>, <a href="/search/quant-ph?searchtype=author&query=Desaules%2C+J">Jean-Yves Desaules</a>, <a href="/search/quant-ph?searchtype=author&query=Gao%2C+Y">Yu Gao</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+N">Ning Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Z">Zexian Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+J">Jiachen Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Zou%2C+Y">Yiren Zou</a>, <a href="/search/quant-ph?searchtype=author&query=Jin%2C+F">Feitong Jin</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+X">Xuhao Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+P">Pengfei Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+H">Hekang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zhen Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Q">Qiujiang Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+J">Junxiang Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Ying%2C+L">Lei Ying</a>, <a href="/search/quant-ph?searchtype=author&query=Papi%C4%87%2C+Z">Zlatko Papi膰</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="2312.10216v2-abstract-short" style="display: inline;"> Emerging quantum technologies hold the promise of unraveling difficult problems ranging from condensed matter to high energy physics, while at the same time motivating the search for unprecedented phenomena in their setting. Here we utilize a custom-built superconducting qubit ladder to realize non-thermalizing states with rich entanglement structures in the middle of the energy spectrum. Despite… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.10216v2-abstract-full').style.display = 'inline'; document.getElementById('2312.10216v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2312.10216v2-abstract-full" style="display: none;"> Emerging quantum technologies hold the promise of unraveling difficult problems ranging from condensed matter to high energy physics, while at the same time motivating the search for unprecedented phenomena in their setting. Here we utilize a custom-built superconducting qubit ladder to realize non-thermalizing states with rich entanglement structures in the middle of the energy spectrum. Despite effectively forming an "infinite" temperature ensemble, these states robustly encode quantum information far from equilibrium, as we demonstrate by measuring the fidelity and entanglement entropy in the quench dynamics of the ladder. Our approach harnesses the recently proposed type of non-ergodic behavior known as "rainbow scar", which allows us to obtain analytically exact eigenfunctions whose ergodicity-breaking properties can be conveniently controlled by randomizing the couplings of the model, without affecting their energy. The on-demand tunability of quantum correlations via disorder allows for in situ control over ergodicity breaking and it provides a knob for designing exotic many-body states that defy thermalization. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.10216v2-abstract-full').style.display = 'none'; document.getElementById('2312.10216v2-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> 3 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 15 December, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 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">11+15 pages</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Science Advances 9, eadj3822 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2305.19873">arXiv:2305.19873</a> <span> [<a href="https://arxiv.org/pdf/2305.19873">pdf</a>, <a href="https://arxiv.org/format/2305.19873">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"> Multi-qubit State Tomography with Few Pauli Measurements </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chai%2C+X">Xudan Chai</a>, <a href="/search/quant-ph?searchtype=author&query=Ma%2C+T">Teng Ma</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Q">Qihao Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Yin%2C+Z">Zhangqi Yin</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+H">Hao Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+Q">Qing Zhao</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="2305.19873v1-abstract-short" style="display: inline;"> In quantum information transformation and quantum computation, the most critical issues are security and accuracy. These features, therefore, stimulate research on quantum state characterization. A characterization tool, Quantum state tomography, reconstructs the density matrix of an unknown quantum state. Theoretically, reconstructing an unknown state using this method can be arbitrarily accurate… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.19873v1-abstract-full').style.display = 'inline'; document.getElementById('2305.19873v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2305.19873v1-abstract-full" style="display: none;"> In quantum information transformation and quantum computation, the most critical issues are security and accuracy. These features, therefore, stimulate research on quantum state characterization. A characterization tool, Quantum state tomography, reconstructs the density matrix of an unknown quantum state. Theoretically, reconstructing an unknown state using this method can be arbitrarily accurate. However, this is less practical owing to the huge burden of measurements and data processing for large numbers of qubits. Even comprising an efficient estimator and a precise algorithm, an optimal tomographic framework can also be overburdened owing to the exponential growth of the measurements. Moreover, the consequential postprocessing of huge amounts of data challenges the capacity of computers. Thus, it is crucial to build an efficient framework that requires fewer measurements but yields an expected accuracy. To this end, we built a tomography schema by which only a few Pauli measurements enable an accurate tomographic reconstruction. Subsequently, this schema was verified as efficient and accurate through numerical simulations on the tomography of multi-qubit quantum states. Furthermore, this schema was proven to be robust through numerical simulations on a noisy superconducting qubit system. Therefore, the tomography schema paves an alternatively effective way to reconstruct the density matrix of a quantum state owing to its efficiency and accuracy, which are essential for quantum state tomography. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.19873v1-abstract-full').style.display = 'none'; document.getElementById('2305.19873v1-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, 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/2304.10760">arXiv:2304.10760</a> <span> [<a href="https://arxiv.org/pdf/2304.10760">pdf</a>, <a href="https://arxiv.org/format/2304.10760">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="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/PhysRevA.108.063703">10.1103/PhysRevA.108.063703 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Magnon squeezing by two-tone driving of a qubit in cavity-magnon-qubit systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Q">Qi Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Cheng%2C+J">Jiong Cheng</a>, <a href="/search/quant-ph?searchtype=author&query=Tan%2C+H">Huatang Tan</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+J">Jie Li</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="2304.10760v4-abstract-short" style="display: inline;"> We propose a scheme for preparing magnon squeezed states in a hybrid cavity-magnon-qubit system. The system consists of a microwave cavity that simultaneously couples to a magnon mode of a macroscopic yttrium-iron-garnet (YIG) sphere via the magnetic-dipole interaction and to a transmon-type superconducting qubit via the electric-dipole interaction. By far detuning from the magnon-qubit system, th… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.10760v4-abstract-full').style.display = 'inline'; document.getElementById('2304.10760v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2304.10760v4-abstract-full" style="display: none;"> We propose a scheme for preparing magnon squeezed states in a hybrid cavity-magnon-qubit system. The system consists of a microwave cavity that simultaneously couples to a magnon mode of a macroscopic yttrium-iron-garnet (YIG) sphere via the magnetic-dipole interaction and to a transmon-type superconducting qubit via the electric-dipole interaction. By far detuning from the magnon-qubit system, the microwave cavity is adiabatically eliminated. The magnon mode and the qubit then get effectively coupled via the mediation of virtual photons of the microwave cavity. We show that by driving the qubit with two microwave fields and by appropriately choosing the drive frequencies and strengths, magnonic parametric amplification can be realized, which leads to magnon quadrature squeezing with the noise below vacuum fluctuation. We provide optimal conditions for achieving magnon squeezing, and moderate squeezing can be obtained using currently available parameters. The generated squeezed states are of a magnon mode involving more than $10^{18}$ spins and thus macroscopic quantum states. The work may find promising applications in quantum information processing and high-precision measurements based on magnons and in the study of macroscopic quantum states. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.10760v4-abstract-full').style.display = 'none'; document.getElementById('2304.10760v4-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 November, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 21 April, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 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">To appear in PRA</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. A 108, 063703 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2211.09802">arXiv:2211.09802</a> <span> [<a href="https://arxiv.org/pdf/2211.09802">pdf</a>, <a href="https://arxiv.org/format/2211.09802">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="Other Condensed Matter">cond-mat.other</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/40/6/060301">10.1088/0256-307X/40/6/060301 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Digital simulation of non-Abelian anyons with 68 programmable superconducting qubits </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Xu%2C+S">Shibo Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Sun%2C+Z">Zheng-Zhi Sun</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+K">Ke Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Xiang%2C+L">Liang Xiang</a>, <a href="/search/quant-ph?searchtype=author&query=Bao%2C+Z">Zehang Bao</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+Z">Zitian Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Shen%2C+F">Fanhao Shen</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+Z">Zixuan Song</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+P">Pengfei Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Ren%2C+W">Wenhui Ren</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+X">Xu Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Dong%2C+H">Hang Dong</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+J">Jinfeng Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+J">Jiachen Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yaozu Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Tan%2C+Z">Ziqi Tan</a>, <a href="/search/quant-ph?searchtype=author&query=Gao%2C+Y">Yu Gao</a>, <a href="/search/quant-ph?searchtype=author&query=Jin%2C+F">Feitong Jin</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+X">Xuhao Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+C">Chuanyu Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+N">Ning Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zou%2C+Y">Yiren Zou</a>, <a href="/search/quant-ph?searchtype=author&query=Zhong%2C+J">Jiarun Zhong</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+A">Aosai Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+W">Weikang Li</a> , et al. (9 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="2211.09802v2-abstract-short" style="display: inline;"> Non-Abelian anyons are exotic quasiparticle excitations hosted by certain topological phases of matter. They break the fermion-boson dichotomy and obey non-Abelian braiding statistics: their interchanges yield unitary operations, rather than merely a phase factor, in a space spanned by topologically degenerate wavefunctions. They are the building blocks of topological quantum computing. However, e… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2211.09802v2-abstract-full').style.display = 'inline'; document.getElementById('2211.09802v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2211.09802v2-abstract-full" style="display: none;"> Non-Abelian anyons are exotic quasiparticle excitations hosted by certain topological phases of matter. They break the fermion-boson dichotomy and obey non-Abelian braiding statistics: their interchanges yield unitary operations, rather than merely a phase factor, in a space spanned by topologically degenerate wavefunctions. They are the building blocks of topological quantum computing. However, experimental observation of non-Abelian anyons and their characterizing braiding statistics is notoriously challenging and has remained elusive hitherto, in spite of various theoretical proposals. Here, we report an experimental quantum digital simulation of projective non-Abelian anyons and their braiding statistics with up to 68 programmable superconducting qubits arranged on a two-dimensional lattice. By implementing the ground states of the toric-code model with twists through quantum circuits, we demonstrate that twists exchange electric and magnetic charges and behave as a particular type of non-Abelian anyons, i.e., the Ising anyons. In particular, we show experimentally that these twists follow the fusion rules and non-Abelian braiding statistics of the Ising type, and can be explored to encode topological logical qubits. Furthermore, we demonstrate how to implement both single- and two-qubit logic gates through applying a sequence of elementary Pauli gates on the underlying physical qubits. Our results demonstrate a versatile quantum digital approach for simulating non-Abelian anyons, offering a new lens into the study of such peculiar quasiparticles. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2211.09802v2-abstract-full').style.display = 'none'; document.getElementById('2211.09802v2-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> 11 May, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 17 November, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Chin. Phys. Lett. 40 060301 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2211.05803">arXiv:2211.05803</a> <span> [<a href="https://arxiv.org/pdf/2211.05803">pdf</a>, <a href="https://arxiv.org/format/2211.05803">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/10.1038/s41567-023-02133-0">10.1038/s41567-023-02133-0 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Observation of many-body Fock space dynamics in two dimensions </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Yao%2C+Y">Yunyan Yao</a>, <a href="/search/quant-ph?searchtype=author&query=Xiang%2C+L">Liang Xiang</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Z">Zexian Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Bao%2C+Z">Zehang Bao</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+Y">Yong-Feng Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+Z">Zixuan Song</a>, <a href="/search/quant-ph?searchtype=author&query=Shi%2C+H">Haohai Shi</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+X">Xuhao Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Jin%2C+F">Feitong Jin</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+J">Jiachen Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+S">Shibo Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+Z">Zitian Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Shen%2C+F">Fanhao Shen</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+N">Ning Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+C">Chuanyu Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yaozu Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Zou%2C+Y">Yiren Zou</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+P">Pengfei Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+H">Hekang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zhen Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+C">Chao Song</a>, <a href="/search/quant-ph?searchtype=author&query=Cheng%2C+C">Chen Cheng</a>, <a href="/search/quant-ph?searchtype=author&query=Mondaini%2C+R">Rubem Mondaini</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+H">H. Wang</a>, <a href="/search/quant-ph?searchtype=author&query=You%2C+J+Q">J. Q. You</a> , et al. (3 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="2211.05803v1-abstract-short" style="display: inline;"> Quantum many-body simulation provides a straightforward way to understand fundamental physics and connect with quantum information applications. However, suffering from exponentially growing Hilbert space size, characterization in terms of few-body probes in real space is often insufficient to tackle challenging problems such as quantum critical behavior and many-body localization (MBL) in higher… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2211.05803v1-abstract-full').style.display = 'inline'; document.getElementById('2211.05803v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2211.05803v1-abstract-full" style="display: none;"> Quantum many-body simulation provides a straightforward way to understand fundamental physics and connect with quantum information applications. However, suffering from exponentially growing Hilbert space size, characterization in terms of few-body probes in real space is often insufficient to tackle challenging problems such as quantum critical behavior and many-body localization (MBL) in higher dimensions. Here, we experimentally employ a new paradigm on a superconducting quantum processor, exploring such elusive questions from a Fock space view: mapping the many-body system onto an unconventional Anderson model on a complex Fock space network of many-body states. By observing the wave packet propagating in Fock space and the emergence of a statistical ergodic ensemble, we reveal a fresh picture for characterizing representative many-body dynamics: thermalization, localization, and scarring. In addition, we observe a quantum critical regime of anomalously enhanced wave packet width and deduce a critical point from the maximum wave packet fluctuations, which lend support for the two-dimensional MBL transition in finite-sized systems. Our work unveils a new perspective of exploring many-body physics in Fock space, demonstrating its practical applications on contentious MBL aspects such as criticality and dimensionality. Moreover, the entire protocol is universal and scalable, paving the way to finally solve a broader range of controversial many-body problems on future larger quantum devices. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2211.05803v1-abstract-full').style.display = 'none'; document.getElementById('2211.05803v1-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 November, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 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">8 pages, 4 figures + supplementary information</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2204.01738">arXiv:2204.01738</a> <span> [<a href="https://arxiv.org/pdf/2204.01738">pdf</a>, <a href="https://arxiv.org/format/2204.01738">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="Artificial Intelligence">cs.AI</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/10.1038/s43588-022-00351-9">10.1038/s43588-022-00351-9 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Experimental quantum adversarial learning with programmable superconducting qubits </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Ren%2C+W">Wenhui Ren</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+W">Weikang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+S">Shibo Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+K">Ke Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Jiang%2C+W">Wenjie Jiang</a>, <a href="/search/quant-ph?searchtype=author&query=Jin%2C+F">Feitong Jin</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+X">Xuhao Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+J">Jiachen Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+Z">Zixuan Song</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+P">Pengfei Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Dong%2C+H">Hang Dong</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+X">Xu Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+J">Jinfeng Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Gao%2C+Y">Yu Gao</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+C">Chuanyu Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yaozu Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+B">Bing Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Q">Qiujiang Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+H">Hekang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zhen Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Biamonte%2C+J">Jacob Biamonte</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+C">Chao Song</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+D">Dong-Ling Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+H">H. Wang</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="2204.01738v1-abstract-short" style="display: inline;"> Quantum computing promises to enhance machine learning and artificial intelligence. Different quantum algorithms have been proposed to improve a wide spectrum of machine learning tasks. Yet, recent theoretical works show that, similar to traditional classifiers based on deep classical neural networks, quantum classifiers would suffer from the vulnerability problem: adding tiny carefully-crafted pe… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2204.01738v1-abstract-full').style.display = 'inline'; document.getElementById('2204.01738v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2204.01738v1-abstract-full" style="display: none;"> Quantum computing promises to enhance machine learning and artificial intelligence. Different quantum algorithms have been proposed to improve a wide spectrum of machine learning tasks. Yet, recent theoretical works show that, similar to traditional classifiers based on deep classical neural networks, quantum classifiers would suffer from the vulnerability problem: adding tiny carefully-crafted perturbations to the legitimate original data samples would facilitate incorrect predictions at a notably high confidence level. This will pose serious problems for future quantum machine learning applications in safety and security-critical scenarios. Here, we report the first experimental demonstration of quantum adversarial learning with programmable superconducting qubits. We train quantum classifiers, which are built upon variational quantum circuits consisting of ten transmon qubits featuring average lifetimes of 150 $渭$s, and average fidelities of simultaneous single- and two-qubit gates above 99.94% and 99.4% respectively, with both real-life images (e.g., medical magnetic resonance imaging scans) and quantum data. We demonstrate that these well-trained classifiers (with testing accuracy up to 99%) can be practically deceived by small adversarial perturbations, whereas an adversarial training process would significantly enhance their robustness to such perturbations. Our results reveal experimentally a crucial vulnerability aspect of quantum learning systems under adversarial scenarios and demonstrate an effective defense strategy against adversarial attacks, which provide a valuable guide for quantum artificial intelligence applications with both near-term and future quantum devices. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2204.01738v1-abstract-full').style.display = 'none'; document.getElementById('2204.01738v1-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 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">26 pages, 17 figures, 8 algorithms</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Computational Science 2, 711 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2201.06768">arXiv:2201.06768</a> <span> [<a href="https://arxiv.org/pdf/2201.06768">pdf</a>, <a href="https://arxiv.org/format/2201.06768">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.abo6213">10.1126/science.abo6213 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Few-cycle vacuum squeezing in nanophotonics </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Nehra%2C+R">Rajveer Nehra</a>, <a href="/search/quant-ph?searchtype=author&query=Sekine%2C+R">Ryoto Sekine</a>, <a href="/search/quant-ph?searchtype=author&query=Ledezma%2C+L">Luis Ledezma</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Q">Qiushi Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Gray%2C+R+M">Robert M. Gray</a>, <a href="/search/quant-ph?searchtype=author&query=Roy%2C+A">Arkadev Roy</a>, <a href="/search/quant-ph?searchtype=author&query=Marandi%2C+A">Alireza Marandi</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="2201.06768v1-abstract-short" style="display: inline;"> One of the most fundamental quantum states of light is squeezed vacuum, in which noise in one of the quadratures is less than the standard quantum noise limit. Significant progress has been made in the generation of optical squeezed vacuum and its utilization for numerous applications. However, it remains challenging to generate, manipulate, and measure such quantum states in nanophotonics with pe… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2201.06768v1-abstract-full').style.display = 'inline'; document.getElementById('2201.06768v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2201.06768v1-abstract-full" style="display: none;"> One of the most fundamental quantum states of light is squeezed vacuum, in which noise in one of the quadratures is less than the standard quantum noise limit. Significant progress has been made in the generation of optical squeezed vacuum and its utilization for numerous applications. However, it remains challenging to generate, manipulate, and measure such quantum states in nanophotonics with performances required for a wide range of scalable quantum information systems. Here, we overcome this challenge in lithium niobate nanophotonics by utilizing ultrashort-pulse phase-sensitive amplifiers for both generation and all-optical measurement of squeezed states on the same chip. We generate a squeezed state spanning over more than 25 THz of bandwidth supporting only a few optical cycles, and measure a maximum of 4.9 dB of squeezing ($\sim$11 dB inferred). This level of squeezing surpasses the requirements for a wide range of quantum information systems. Our results on generation and measurement of few-optical-cycle squeezed states in nanophotonics enable a practical path towards scalable quantum information systems with THz clock rates and open opportunities for studying non-classical nature of light in the sub-cycle regime. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2201.06768v1-abstract-full').style.display = 'none'; document.getElementById('2201.06768v1-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 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">8 pages, 4 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/2201.03438">arXiv:2201.03438</a> <span> [<a href="https://arxiv.org/pdf/2201.03438">pdf</a>, <a href="https://arxiv.org/ps/2201.03438">ps</a>, <a href="https://arxiv.org/format/2201.03438">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="Statistical Mechanics">cond-mat.stat-mech</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/s41567-022-01784-9">10.1038/s41567-022-01784-9 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Many-body Hilbert space scarring on a superconducting processor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+P">Pengfei Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Dong%2C+H">Hang Dong</a>, <a href="/search/quant-ph?searchtype=author&query=Gao%2C+Y">Yu Gao</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+L">Liangtian Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Hao%2C+J">Jie Hao</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Q">Qiujiang Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+J">Jiachen Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+J">Jinfeng Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+B">Bobo Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Ren%2C+W">Wenhui Ren</a>, <a href="/search/quant-ph?searchtype=author&query=Yao%2C+Y">Yunyan Yao</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+X">Xu Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+S">Shibo Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+K">Ke Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Jin%2C+F">Feitong Jin</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+X">Xuhao Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+H">Hekang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+C">Chao Song</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zhen Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+F">Fangli Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Papi%C4%87%2C+Z">Zlatko Papi膰</a>, <a href="/search/quant-ph?searchtype=author&query=Ying%2C+L">Lei Ying</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+H">H. Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Lai%2C+Y">Ying-Cheng Lai</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="2201.03438v2-abstract-short" style="display: inline;"> Quantum many-body scarring (QMBS) -- a recently discovered form of weak ergodicity breaking in strongly-interacting quantum systems -- presents opportunities for mitigating thermalization-induced decoherence in quantum information processsing. However, the existing experimental realizations of QMBS are based on kinetically-constrained systems where an emergent dynamical symmetry "shields" such sta… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2201.03438v2-abstract-full').style.display = 'inline'; document.getElementById('2201.03438v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2201.03438v2-abstract-full" style="display: none;"> Quantum many-body scarring (QMBS) -- a recently discovered form of weak ergodicity breaking in strongly-interacting quantum systems -- presents opportunities for mitigating thermalization-induced decoherence in quantum information processsing. However, the existing experimental realizations of QMBS are based on kinetically-constrained systems where an emergent dynamical symmetry "shields" such states from the thermalizing bulk of the spectrum. Here, we experimentally realize a distinct kind of QMBS phenomena by approximately decoupling a part of the many-body Hilbert space in the computational basis. Utilizing a programmable superconducting processor with 30 qubits and tunable couplings, we realize Hilbert space scarring in a non-constrained model in different geometries, including a linear chain as well as a quasi-one-dimensional comb geometry. By performing full quantum state tomography on 4-qubit subsystems, we provide strong evidence for QMBS states by measuring qubit population dynamics, quantum fidelity and entanglement entropy following a quench from initial product states. Our experimental findings broaden the realm of QMBS mechanisms and pave the way to exploiting correlations in QMBS states for applications in quantum information technology. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2201.03438v2-abstract-full').style.display = 'none'; document.getElementById('2201.03438v2-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 March, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 10 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">Report number:</span> s41567-022-01784-9 </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Physics 19, 120 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2112.14922">arXiv:2112.14922</a> <span> [<a href="https://arxiv.org/pdf/2112.14922">pdf</a>, <a href="https://arxiv.org/format/2112.14922">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/s41567-022-01813-7">10.1038/s41567-022-01813-7 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Scalable algorithm simplification using quantum AND logic </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chu%2C+J">Ji Chu</a>, <a href="/search/quant-ph?searchtype=author&query=He%2C+X">Xiaoyu He</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Y">Yuxuan Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Yuan%2C+J">Jiahao Yuan</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+L">Libo Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Q">Qihao Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Hai%2C+Y">Yongju Hai</a>, <a href="/search/quant-ph?searchtype=author&query=Han%2C+Z">Zhikun Han</a>, <a href="/search/quant-ph?searchtype=author&query=Hu%2C+C">Chang-Kang Hu</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+W">Wenhui Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Jia%2C+H">Hao Jia</a>, <a href="/search/quant-ph?searchtype=author&query=Jiao%2C+D">Dawei Jiao</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+Y">Yang Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Ni%2C+Z">Zhongchu Ni</a>, <a href="/search/quant-ph?searchtype=author&query=Pan%2C+X">Xianchuang Pan</a>, <a href="/search/quant-ph?searchtype=author&query=Qiu%2C+J">Jiawei Qiu</a>, <a href="/search/quant-ph?searchtype=author&query=Wei%2C+W">Weiwei Wei</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+Z">Zusheng Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+J">Jiajian Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Z">Zhida Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Zou%2C+W">Wanjing Zou</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Y">Yuanzhen Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+X">Xiaowei Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+X">Xiuhao Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Hu%2C+L">Ling Hu</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="2112.14922v1-abstract-short" style="display: inline;"> Implementing quantum algorithms on realistic hardware requires translating high-level global operations into sequences of native elementary gates, a process known as quantum compiling. Physical limitations, such as constraints in connectivity and gate alphabets, often result in unacceptable implementation costs. To enable successful near-term applications, it is crucial to optimize compilation by… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2112.14922v1-abstract-full').style.display = 'inline'; document.getElementById('2112.14922v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2112.14922v1-abstract-full" style="display: none;"> Implementing quantum algorithms on realistic hardware requires translating high-level global operations into sequences of native elementary gates, a process known as quantum compiling. Physical limitations, such as constraints in connectivity and gate alphabets, often result in unacceptable implementation costs. To enable successful near-term applications, it is crucial to optimize compilation by exploiting the potential capabilities of existing hardware. Here, we implement a resource-efficient construction for a quantum version of AND logic that can reduce the cost, enabling the execution of key quantum circuits. On a high-scalability superconducting quantum processor, we demonstrate low-depth synthesis of high-fidelity generalized Toffoli gates with up to 8 qubits and Grover's search algorithm in a search space of up to 64 entries; both are the largest such implementations in scale to date. Our experimental demonstration illustrates a scalable implementation of simplifying quantum algorithms, paving the way for larger, more meaningful quantum applications on noisy devices. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2112.14922v1-abstract-full').style.display = 'none'; document.getElementById('2112.14922v1-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 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> Nature Physics 19, 126 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2110.05334">arXiv:2110.05334</a> <span> [<a href="https://arxiv.org/pdf/2110.05334">pdf</a>, <a href="https://arxiv.org/format/2110.05334">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="Computational Physics">physics.comp-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.105.012616">10.1103/PhysRevA.105.012616 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Optimizing quantum control pulses with complex constraints and few variables through Tensorflow </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Song%2C+Y">Yao Song</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+J">Junning Li</a>, <a href="/search/quant-ph?searchtype=author&query=Hai%2C+Y">Yong-Ju Hai</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Q">Qihao Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+X">Xiu-Hao Deng</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="2110.05334v2-abstract-short" style="display: inline;"> Applying optimal control algorithms on realistic quantum systems confronts two key challenges: to efficiently adopt physical constraints in the optimization and to minimize the variables for the convenience of experimental tune-ups. In order to resolve these issues, we propose a novel algorithm by incorporating multiple constraints into the gradient optimization over piece-wise pulse constant valu… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2110.05334v2-abstract-full').style.display = 'inline'; document.getElementById('2110.05334v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2110.05334v2-abstract-full" style="display: none;"> Applying optimal control algorithms on realistic quantum systems confronts two key challenges: to efficiently adopt physical constraints in the optimization and to minimize the variables for the convenience of experimental tune-ups. In order to resolve these issues, we propose a novel algorithm by incorporating multiple constraints into the gradient optimization over piece-wise pulse constant values, which are transformed to contained numbers of the finite Fourier basis for bandwidth control. Such complex constraints and variable transformation involved in the optimization introduce extreme difficulty in calculating gradients. We resolve this issue efficiently utilizing auto-differentiation on Tensorflow. We test our algorithm by finding smooth control pulses to implement single-qubit and two-qubit gates for superconducting transmon qubits with always-on interaction, which remains a challenge of quantum control in various qubit systems. Our algorithm provides a promising optimal quantum control approach that is friendly to complex and optional physical constraints. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2110.05334v2-abstract-full').style.display = 'none'; document.getElementById('2110.05334v2-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 October, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 11 October, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2021. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2109.05577">arXiv:2109.05577</a> <span> [<a href="https://arxiv.org/pdf/2109.05577">pdf</a>, <a href="https://arxiv.org/format/2109.05577">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="Superconductivity">cond-mat.supr-con</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/s41586-022-04854-3">10.1038/s41586-022-04854-3 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Observation of a symmetry-protected topological time crystal with superconducting qubits </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+X">Xu Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Jiang%2C+W">Wenjie Jiang</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+J">Jinfeng Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+K">Ke Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+J">Jiachen Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+P">Pengfei Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Ren%2C+W">Wenhui Ren</a>, <a href="/search/quant-ph?searchtype=author&query=Dong%2C+H">Hang Dong</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+S">Shibo Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Gao%2C+Y">Yu Gao</a>, <a href="/search/quant-ph?searchtype=author&query=Jin%2C+F">Feitong Jin</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+X">Xuhao Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Q">Qiujiang Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+H">Hekang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+C">Chao Song</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zhen Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+D">Dong-Ling Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+H">H. Wang</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="2109.05577v1-abstract-short" style="display: inline;"> We report the observation of a symmetry-protected topological time crystal, which is implemented with an array of programmable superconducting qubits. Unlike the time crystals reported in previous experiments, where spontaneous breaking of the discrete time translational symmetry occurs for local observables throughout the whole system, the topological time crystal observed in our experiment break… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2109.05577v1-abstract-full').style.display = 'inline'; document.getElementById('2109.05577v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2109.05577v1-abstract-full" style="display: none;"> We report the observation of a symmetry-protected topological time crystal, which is implemented with an array of programmable superconducting qubits. Unlike the time crystals reported in previous experiments, where spontaneous breaking of the discrete time translational symmetry occurs for local observables throughout the whole system, the topological time crystal observed in our experiment breaks the time translational symmetry only at the boundaries and has trivial dynamics in the bulk. More concretely, we observe robust long-lived temporal correlations and sub-harmonic temporal response for the edge spins up to 40 driving cycles. We demonstrate that the sub-harmonic response is independent of whether the initial states are random product states or symmetry-protected topological states, and experimentally map out the phase boundary between the time crystalline and thermal phases. Our work paves the way to exploring peculiar non-equilibrium phases of matter emerged from the interplay between topology and localization as well as periodic driving, with current noisy intermediate-scale quantum processors. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2109.05577v1-abstract-full').style.display = 'none'; document.getElementById('2109.05577v1-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 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">8 pages main text, and 11 pages for supplementary materials</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature 607, 468 (2022) </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/2104.08262">arXiv:2104.08262</a> <span> [<a href="https://arxiv.org/pdf/2104.08262">pdf</a>, <a href="https://arxiv.org/format/2104.08262">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="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/OPTICA.442332">10.1364/OPTICA.442332 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Intense optical parametric amplification in dispersion engineered nanophotonic lithium niobate waveguides </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Ledezma%2C+L">Luis Ledezma</a>, <a href="/search/quant-ph?searchtype=author&query=Sekine%2C+R">Ryoto Sekine</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Q">Qiushi Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Nehra%2C+R">Rajveer Nehra</a>, <a href="/search/quant-ph?searchtype=author&query=Jahani%2C+S">Saman Jahani</a>, <a href="/search/quant-ph?searchtype=author&query=Marandi%2C+A">Alireza Marandi</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="2104.08262v3-abstract-short" style="display: inline;"> Strong amplification in integrated photonics is one of the most desired optical functionalities for computing, communications, sensing, and quantum information processing. Semiconductor gain and cubic nonlinearities, such as four-wave mixing and stimulated Raman and Brillouin scattering, have been among the most studied amplification mechanisms on chip. Alternatively, material platforms with stron… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2104.08262v3-abstract-full').style.display = 'inline'; document.getElementById('2104.08262v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2104.08262v3-abstract-full" style="display: none;"> Strong amplification in integrated photonics is one of the most desired optical functionalities for computing, communications, sensing, and quantum information processing. Semiconductor gain and cubic nonlinearities, such as four-wave mixing and stimulated Raman and Brillouin scattering, have been among the most studied amplification mechanisms on chip. Alternatively, material platforms with strong quadratic nonlinearities promise numerous advantages with respect to gain and bandwidth, among which nanophotonic lithium niobate is one of the most promising candidates. Here, we combine quasi-phase matching with dispersion engineering in nanophotonic lithium niobate waveguides and achieve intense optical parametric amplification. We measure a broadband phase-sensitive on-chip amplification larger than 45 dB/cm in a 2.5-mm-long waveguide. We further confirm high gain operation in the degenerate and non-degenerate regimes by amplifying vacuum fluctuations to macroscopic levels in a 6-mm-long waveguide, with on-chip gains exceeding 100 dB/cm over 600 nm of bandwidth around 2 $渭$m. Our results unlock new possibilities for on-chip few-cycle nonlinear optics, mid-infrared photonics, and quantum photonics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2104.08262v3-abstract-full').style.display = 'none'; document.getElementById('2104.08262v3-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 March, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 16 April, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 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 pages, 4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Optica 9(3) 303-308 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2103.07821">arXiv:2103.07821</a> <span> [<a href="https://arxiv.org/pdf/2103.07821">pdf</a>, <a href="https://arxiv.org/ps/2103.07821">ps</a>, <a href="https://arxiv.org/format/2103.07821">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/10.1002/andp.202000589">10.1002/andp.202000589 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Operator transpose within normal ordering and its applications for quantifying entanglement </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Hu%2C+L">Liyun Hu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+L">Luping Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+X">Xiaoting Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Ye%2C+W">Wei Ye</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Q">Qin Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Fan%2C+H">Hongyi Fan</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="2103.07821v1-abstract-short" style="display: inline;"> Partial transpose is an important operation for quantifying the entanglement, here we study the (partial) transpose of any single (two-mode) operators. Using the Fock-basis expansion, it is found that the transposed operator of an arbitrary operator can be obtained by replacement of a^{鈥爙(a) by a(a^{鈥爙) instead of c-number within normal ordering form. The transpose of displacement operator and Wig… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2103.07821v1-abstract-full').style.display = 'inline'; document.getElementById('2103.07821v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2103.07821v1-abstract-full" style="display: none;"> Partial transpose is an important operation for quantifying the entanglement, here we study the (partial) transpose of any single (two-mode) operators. Using the Fock-basis expansion, it is found that the transposed operator of an arbitrary operator can be obtained by replacement of a^{鈥爙(a) by a(a^{鈥爙) instead of c-number within normal ordering form. The transpose of displacement operator and Wigner operator are studied, from which the relation of Wigner function, characteristics function and average values such as covariance matrix are constructed between density operator and transposed density operator. These observations can be further extended to multi-mode cases. As applications, the partial transpose of two-mode squeezed operator and the entanglement of two-mode squeezed vacuum through a laser channel are considered. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2103.07821v1-abstract-full').style.display = 'none'; document.getElementById('2103.07821v1-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 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">10 pages, no figure</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">MSC Class:</span> A.0 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2102.11562">arXiv:2102.11562</a> <span> [<a href="https://arxiv.org/pdf/2102.11562">pdf</a>, <a href="https://arxiv.org/ps/2102.11562">ps</a>, <a href="https://arxiv.org/format/2102.11562">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.104.022210">10.1103/PhysRevA.104.022210 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Modified quantum delayed-choice experiment without quantum control </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Q">Qi Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+W">Wen-Jie Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+G">Gang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+T">Tiancai Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+H">Hong-Fu Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+S">Shou Zhang</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="2102.11562v1-abstract-short" style="display: inline;"> Wheeler's delayed-choice experiment delays the decision to observe either the wave or particle behavior of a photon until after it has entered the interferometer, and the quantum delayed-choice experiment provides the possibility of observing the wave and particle behavior simultaneously by introducing quantum control device. We here propose a modified quantum delayed-choice experiment without qua… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2102.11562v1-abstract-full').style.display = 'inline'; document.getElementById('2102.11562v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2102.11562v1-abstract-full" style="display: none;"> Wheeler's delayed-choice experiment delays the decision to observe either the wave or particle behavior of a photon until after it has entered the interferometer, and the quantum delayed-choice experiment provides the possibility of observing the wave and particle behavior simultaneously by introducing quantum control device. We here propose a modified quantum delayed-choice experiment without quantum control or entanglement assistance, in which a photon can be prepared in a wave-particle superposition state and the morphing behavior of wave-to-particle transition can be observed easily. It is demonstrated that the presented scheme can allow us to rule out classical hidden variable models in a device-independent manner via violating dimension witness. We also extend the scheme to the situation of two degrees of freedom, first constructing a hybrid quantum delayed-choice experiment which enables simultaneous observation of a photon's wave and particle behaviors in different degrees of freedom, and then proposing a scheme to prepare the single-photon wave-particle entanglement. This study is not only meaningful to explore the wave and particle properties of photons, but also provides potential for the research of the single-particle nonlocality from the perspective of the wave-particle degree of freedom. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2102.11562v1-abstract-full').style.display = 'none'; document.getElementById('2102.11562v1-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 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">17 pages, 5 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. A 104, 022210 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2011.13895">arXiv:2011.13895</a> <span> [<a href="https://arxiv.org/pdf/2011.13895">pdf</a>, <a href="https://arxiv.org/format/2011.13895">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.127.240502">10.1103/PhysRevLett.127.240502 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Stark many-body localization on a superconducting quantum processor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Q">Qiujiang Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Cheng%2C+C">Chen Cheng</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+H">Hekang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+S">Shibo Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+P">Pengfei Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zhen Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+C">Chao Song</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+W">Wuxin Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Ren%2C+W">Wenhui Ren</a>, <a href="/search/quant-ph?searchtype=author&query=Dong%2C+H">Hang Dong</a>, <a href="/search/quant-ph?searchtype=author&query=Mondaini%2C+R">Rubem Mondaini</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+H">H. Wang</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="2011.13895v1-abstract-short" style="display: inline;"> Quantum emulators, owing to their large degree of tunability and control, allow the observation of fine aspects of closed quantum many-body systems, as either the regime where thermalization takes place or when it is halted by the presence of disorder. The latter, dubbed many-body localization (MBL) phenomenon, describes the non-ergodic behavior that is dynamically identified by the preservation o… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2011.13895v1-abstract-full').style.display = 'inline'; document.getElementById('2011.13895v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2011.13895v1-abstract-full" style="display: none;"> Quantum emulators, owing to their large degree of tunability and control, allow the observation of fine aspects of closed quantum many-body systems, as either the regime where thermalization takes place or when it is halted by the presence of disorder. The latter, dubbed many-body localization (MBL) phenomenon, describes the non-ergodic behavior that is dynamically identified by the preservation of local information and slow entanglement growth. Here, we provide a precise observation of this same phenomenology in the case the onsite energy landscape is not disordered, but rather linearly varied, emulating the Stark MBL. To this end, we construct a quantum device composed of thirty-two superconducting qubits, faithfully reproducing the relaxation dynamics of a non-integrable spin model. Our results describe the real-time evolution at sizes that surpass what is currently attainable by exact simulations in classical computers, signaling the onset of quantum advantage, thus bridging the way for quantum computation as a resource for solving out-of-equilibrium many-body problems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2011.13895v1-abstract-full').style.display = 'none'; document.getElementById('2011.13895v1-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 November, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 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">8 pages, 5 figures; + Supplementary Materials: 12 pages, 11 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, 240502 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2009.12827">arXiv:2009.12827</a> <span> [<a href="https://arxiv.org/pdf/2009.12827">pdf</a>, <a href="https://arxiv.org/format/2009.12827">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/s41534-021-00503-1">10.1038/s41534-021-00503-1 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Realizing a quantum generative adversarial network using a programmable superconducting processor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Huang%2C+K">Kaixuan Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zheng-An Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+C">Chao Song</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+K">Kai Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+H">Hekang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zhen Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Q">Qiujiang Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+Z">Zixuan Song</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+Z">Zhi-Bo Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Zheng%2C+D">Dongning Zheng</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+D">Dong-Ling Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+H">H. Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Tian%2C+J">Jian-Guo Tian</a>, <a href="/search/quant-ph?searchtype=author&query=Fan%2C+H">Heng Fan</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="2009.12827v1-abstract-short" style="display: inline;"> Generative adversarial networks are an emerging technique with wide applications in machine learning, which have achieved dramatic success in a number of challenging tasks including image and video generation. When equipped with quantum processors, their quantum counterparts--called quantum generative adversarial networks (QGANs)--may even exhibit exponential advantages in certain machine learning… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2009.12827v1-abstract-full').style.display = 'inline'; document.getElementById('2009.12827v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2009.12827v1-abstract-full" style="display: none;"> Generative adversarial networks are an emerging technique with wide applications in machine learning, which have achieved dramatic success in a number of challenging tasks including image and video generation. When equipped with quantum processors, their quantum counterparts--called quantum generative adversarial networks (QGANs)--may even exhibit exponential advantages in certain machine learning applications. Here, we report an experimental implementation of a QGAN using a programmable superconducting processor, in which both the generator and the discriminator are parameterized via layers of single- and multi-qubit quantum gates. The programmed QGAN runs automatically several rounds of adversarial learning with quantum gradients to achieve a Nash equilibrium point, where the generator can replicate data samples that mimic the ones from the training set. Our implementation is promising to scale up to noisy intermediate-scale quantum devices, thus paving the way for experimental explorations of quantum advantages in practical applications with near-term quantum technologies. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2009.12827v1-abstract-full').style.display = 'none'; document.getElementById('2009.12827v1-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 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">Journal ref:</span> npj Quantum Inf 7, 165 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2009.07522">arXiv:2009.07522</a> <span> [<a href="https://arxiv.org/pdf/2009.07522">pdf</a>, <a href="https://arxiv.org/format/2009.07522">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/10.1364/OPTICA.415569">10.1364/OPTICA.415569 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Non-Dissipative Non-Hermitian Dynamics and Exceptional Points in Coupled Optical Parametric Oscillators </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Roy%2C+A">Arkadev Roy</a>, <a href="/search/quant-ph?searchtype=author&query=Jahani%2C+S">Saman Jahani</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Q">Qiushi Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Dutt%2C+A">Avik Dutt</a>, <a href="/search/quant-ph?searchtype=author&query=Fan%2C+S">Shanhui Fan</a>, <a href="/search/quant-ph?searchtype=author&query=Miri%2C+M">Mohammad-Ali Miri</a>, <a href="/search/quant-ph?searchtype=author&query=Marandi%2C+A">Alireza Marandi</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="2009.07522v1-abstract-short" style="display: inline;"> Engineered non-Hermitian systems featuring exceptional points can lead to a host of extraordinary phenomena in diverse fields ranging from photonics, acoustics, opto-mechanics, electronics, to atomic physics. Here we introduce and present non-Hermitian dynamics of coupled optical parametric oscillators (OPOs) arising from phase-sensitive amplification and de-amplification, and show their distinct… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2009.07522v1-abstract-full').style.display = 'inline'; document.getElementById('2009.07522v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2009.07522v1-abstract-full" style="display: none;"> Engineered non-Hermitian systems featuring exceptional points can lead to a host of extraordinary phenomena in diverse fields ranging from photonics, acoustics, opto-mechanics, electronics, to atomic physics. Here we introduce and present non-Hermitian dynamics of coupled optical parametric oscillators (OPOs) arising from phase-sensitive amplification and de-amplification, and show their distinct advantages over conventional non-Hermitian systems relying on laser gain and loss. OPO-based non-Hermitian systems can benefit from the instantaneous nature of the parametric gain, noiseless phase-sensitive amplification, and rich quantum and classical nonlinear dynamics. We show that two coupled OPOs can exhibit spectral anti-PT symmetry and an exceptional point between its degenerate and non-degenerate operation regimes. To demonstrate the distinct potentials of the coupled OPO system compared to conventional non-Hermitian systems, we present higher-order exceptional points with two OPOs, tunable Floquet exceptional points in a reconfigurable dynamic non-Hermitian system, and generation of squeezed vacuum around exceptional points, all of which are not easy to realize in other non-Hermitian platforms. Our results show that coupled OPOs are an outstanding non-Hermitian setting with unprecedented opportunities in realizing nonlinear dynamical systems for enhanced sensing and quantum information processing. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2009.07522v1-abstract-full').style.display = 'none'; document.getElementById('2009.07522v1-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 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">Journal ref:</span> Optica 8 (3), 415-421 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2007.13682">arXiv:2007.13682</a> <span> [<a href="https://arxiv.org/pdf/2007.13682">pdf</a>, <a href="https://arxiv.org/format/2007.13682">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="High Energy Physics - Theory">hep-th</span> </div> </div> <p class="title is-5 mathjax"> Observation of Two-Vertex Four-Dimensional Spin Foam Amplitudes with a 10-qubit Superconducting Quantum Processor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+P">Pengfei Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Z">Zichang Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+C">Chao Song</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Q">Qiujiang Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+Z">Zixuan Song</a>, <a href="/search/quant-ph?searchtype=author&query=Dong%2C+H">Hang Dong</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zhen Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Hekang%2C+L">Li Hekang</a>, <a href="/search/quant-ph?searchtype=author&query=Han%2C+M">Muxin Han</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+H">Haohua Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Wan%2C+Y">Yidun Wan</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="2007.13682v1-abstract-short" style="display: inline;"> Quantum computers are an increasingly hopeful means for understanding large quantum many-body systems bearing high computational complexity. Such systems exhibit complex evolutions of quantum states, and are prevailing in fundamental physics, e.g., quantum gravity. Computing the transition amplitudes between different quantum states by quantum computers is one of the promising ways to solve such c… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2007.13682v1-abstract-full').style.display = 'inline'; document.getElementById('2007.13682v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2007.13682v1-abstract-full" style="display: none;"> Quantum computers are an increasingly hopeful means for understanding large quantum many-body systems bearing high computational complexity. Such systems exhibit complex evolutions of quantum states, and are prevailing in fundamental physics, e.g., quantum gravity. Computing the transition amplitudes between different quantum states by quantum computers is one of the promising ways to solve such computational complexity problems. In this work, we apply a 10-qubit superconducting quantum processor, where the all-to-all circuit connectivity enables a many-body entangling gate that is highly efficient for state generation, to studying the transition amplitudes in loop quantum gravity. With the device metrics such as qubit coherence, control accuracy, and integration level being continuously improved, superconducting quantum processors are expected to outperform their classical counterparts in handling many-body dynamics and may lead to a deeper understanding of quantum gravity. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2007.13682v1-abstract-full').style.display = 'none'; document.getElementById('2007.13682v1-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 July, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 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">12 Pages, 8 figures, 5 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/2007.10019">arXiv:2007.10019</a> <span> [<a href="https://arxiv.org/pdf/2007.10019">pdf</a>, <a href="https://arxiv.org/format/2007.10019">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.126.080501">10.1103/PhysRevLett.126.080501 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Scalable evaluation of quantum-circuit error loss using Clifford sampling </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zhen Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Y">Yanzhu Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+Z">Zixuan Song</a>, <a href="/search/quant-ph?searchtype=author&query=Qin%2C+D">Dayue Qin</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+H">Hekang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Q">Qiujiang Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+H">H. Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+C">Chao Song</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Ying Li</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="2007.10019v1-abstract-short" style="display: inline;"> A major challenge in developing quantum computing technologies is to accomplish high precision tasks by utilizing multiplex optimization approaches, on both the physical system and algorithm levels. Loss functions assessing the overall performance of quantum circuits can provide the foundation for many optimization techniques. In this paper, we use the quadratic error loss and the final-state fide… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2007.10019v1-abstract-full').style.display = 'inline'; document.getElementById('2007.10019v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2007.10019v1-abstract-full" style="display: none;"> A major challenge in developing quantum computing technologies is to accomplish high precision tasks by utilizing multiplex optimization approaches, on both the physical system and algorithm levels. Loss functions assessing the overall performance of quantum circuits can provide the foundation for many optimization techniques. In this paper, we use the quadratic error loss and the final-state fidelity loss to characterize quantum circuits. We find that the distribution of computation error is approximately Gaussian, which in turn justifies the quadratic error loss. It is shown that these loss functions can be efficiently evaluated in a scalable way by sampling from Clifford-dominated circuits. We demonstrate the results by numerically simulating ten-qubit noisy quantum circuits with various error models as well as executing four-qubit circuits with up to ten layers of two-qubit gates on a superconducting quantum processor. Our results pave the way towards the optimization-based quantum device and algorithm design in the intermediate-scale quantum regime. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2007.10019v1-abstract-full').style.display = 'none'; document.getElementById('2007.10019v1-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 July, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 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">5+11 pages, 16 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. 126, 080501 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2004.07531">arXiv:2004.07531</a> <span> [<a href="https://arxiv.org/pdf/2004.07531">pdf</a>, <a href="https://arxiv.org/ps/2004.07531">ps</a>, <a href="https://arxiv.org/format/2004.07531">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="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.125.133601">10.1103/PhysRevLett.125.133601 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Simultaneous excitation of two noninteracting atoms with time-frequency correlated photon pairs in a superconducting circuit </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Ren%2C+W">Wenhui Ren</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+W">Wuxin Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+C">Chao Song</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+H">Hekang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Q">Qiujiang Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zhen Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zheng%2C+D">Dongning Zheng</a>, <a href="/search/quant-ph?searchtype=author&query=Agarwal%2C+G+S">Girish S. Agarwal</a>, <a href="/search/quant-ph?searchtype=author&query=Scully%2C+M+O">Marlan O. Scully</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+S">Shi-Yao Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+H">H. Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+D">Da-Wei Wang</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="2004.07531v1-abstract-short" style="display: inline;"> Here we report the first observation of simultaneous excitation of two noninteracting atoms by a pair of time-frequency correlated photons in a superconducting circuit. The strong coupling regime of this process enables the synthesis of a three-body interaction Hamiltonian, which allows the generation of the tripartite Greenberger-Horne-Zeilinger state in a single step with a fidelity as high as 0… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2004.07531v1-abstract-full').style.display = 'inline'; document.getElementById('2004.07531v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2004.07531v1-abstract-full" style="display: none;"> Here we report the first observation of simultaneous excitation of two noninteracting atoms by a pair of time-frequency correlated photons in a superconducting circuit. The strong coupling regime of this process enables the synthesis of a three-body interaction Hamiltonian, which allows the generation of the tripartite Greenberger-Horne-Zeilinger state in a single step with a fidelity as high as 0.95. We further demonstrate the quantum Zeno effect of inhibiting the simultaneous two-atom excitation by continuously measuring whether the first photon is emitted. This work provides a new route in synthesizing many-body interaction Hamiltonian and coherent control of entanglement. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2004.07531v1-abstract-full').style.display = 'none'; document.getElementById('2004.07531v1-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 April, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 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">5 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, 133601 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2003.06086">arXiv:2003.06086</a> <span> [<a href="https://arxiv.org/pdf/2003.06086">pdf</a>, <a href="https://arxiv.org/ps/2003.06086">ps</a>, <a href="https://arxiv.org/format/2003.06086">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.125.160503">10.1103/PhysRevLett.125.160503 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Digital Simulation of Topological Matter on Programmable Quantum Processors </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Mei%2C+F">Feng Mei</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Q">Qihao Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Yu%2C+Y">Ya-Fei Yu</a>, <a href="/search/quant-ph?searchtype=author&query=Xiao%2C+L">Liantuan Xiao</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+S">Shi-Liang Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Jia%2C+S">Suotang Jia</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="2003.06086v2-abstract-short" style="display: inline;"> Simulating the topological phases of matter in synthetic quantum simulators is a topic of considerable interest. Given the universality of digital quantum simulators, the prospect of digitally simulating exotic topological phases is greatly enhanced. However, it is still an open question how to realize digital quantum simulation of topological phases of matter. Here, using common single- and two-q… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2003.06086v2-abstract-full').style.display = 'inline'; document.getElementById('2003.06086v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2003.06086v2-abstract-full" style="display: none;"> Simulating the topological phases of matter in synthetic quantum simulators is a topic of considerable interest. Given the universality of digital quantum simulators, the prospect of digitally simulating exotic topological phases is greatly enhanced. However, it is still an open question how to realize digital quantum simulation of topological phases of matter. Here, using common single- and two-qubit elementary quantum gates, we propose and demonstrate an approach to design topologically protected quantum circuits on the current generation of noisy quantum processors where spin-orbital coupling and related topological matter can be digitally simulated. In particular, a low-depth topological quantum circuit is performed on both IBM and Rigetti quantum processors. In the experiments, we not only observe but also distinguish the 0 and $蟺$ energy topological edge states by measuring qubit excitation distribution at the output of the circuits. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2003.06086v2-abstract-full').style.display = 'none'; document.getElementById('2003.06086v2-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 September, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 12 March, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 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">8 pages, 4 figures, Accepted by PRL</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, 160503 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2001.10187">arXiv:2001.10187</a> <span> [<a href="https://arxiv.org/pdf/2001.10187">pdf</a>, <a href="https://arxiv.org/ps/2001.10187">ps</a>, <a href="https://arxiv.org/format/2001.10187">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.102.023113">10.1103/PhysRevA.102.023113 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Classical and quantum time crystals in a levitated nanoparticle without drive </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yi Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Q">Qihao Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Xiong%2C+A">Anda Xiong</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+T">Tongcang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Yin%2C+Z">Zhang-qi Yin</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="2001.10187v3-abstract-short" style="display: inline;"> Time crystal is defined as a phase of matter spontaneously exhibiting a periodicity in time. Previous studies focused on discrete quantum time crystals under periodic drive. Here, we propose a time crystal model based on a levitated charged nanoparticle in a static magnetic field without drive. Both the classical time crystal in thermal equilibrium and the quantum time crystal in the ground state… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2001.10187v3-abstract-full').style.display = 'inline'; document.getElementById('2001.10187v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2001.10187v3-abstract-full" style="display: none;"> Time crystal is defined as a phase of matter spontaneously exhibiting a periodicity in time. Previous studies focused on discrete quantum time crystals under periodic drive. Here, we propose a time crystal model based on a levitated charged nanoparticle in a static magnetic field without drive. Both the classical time crystal in thermal equilibrium and the quantum time crystal in the ground state can emerge in the spin rotational mode, under the strong magnetic field or the large charge-to-mass ratio limit. Besides, for the first time, the \emph{time polycrystal} is defined and naturally appears in this model. Our model paves a way for realizing time crystals in thermal equilibrium. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2001.10187v3-abstract-full').style.display = 'none'; document.getElementById('2001.10187v3-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 July, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 28 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">Comments:</span> <span class="has-text-grey-dark mathjax">10 pages, 7 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. A 102, 023113 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2001.07998">arXiv:2001.07998</a> <span> [<a href="https://arxiv.org/pdf/2001.07998">pdf</a>, <a href="https://arxiv.org/format/2001.07998">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.2020.07.033">10.1016/j.scib.2020.07.033 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Testing a Quantum Error-Correcting Code on Various Platforms </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Q">Qihao Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+Y">Yuan-Yuan Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Grassl%2C+M">Markus Grassl</a>, <a href="/search/quant-ph?searchtype=author&query=Nie%2C+X">Xinfang Nie</a>, <a href="/search/quant-ph?searchtype=author&query=Xiang%2C+G">Guo-Yong Xiang</a>, <a href="/search/quant-ph?searchtype=author&query=Xin%2C+T">Tao Xin</a>, <a href="/search/quant-ph?searchtype=author&query=Yin%2C+Z">Zhang-Qi Yin</a>, <a href="/search/quant-ph?searchtype=author&query=Zeng%2C+B">Bei Zeng</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="2001.07998v1-abstract-short" style="display: inline;"> Quantum error correction plays an important role in fault-tolerant quantum information processing. It is usually difficult to experimentally realize quantum error correction, as it requires multiple qubits and quantum gates with high fidelity. Here we propose a simple quantum error-correcting code for the detected amplitude damping channel. The code requires only two qubits. We implement the encod… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2001.07998v1-abstract-full').style.display = 'inline'; document.getElementById('2001.07998v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2001.07998v1-abstract-full" style="display: none;"> Quantum error correction plays an important role in fault-tolerant quantum information processing. It is usually difficult to experimentally realize quantum error correction, as it requires multiple qubits and quantum gates with high fidelity. Here we propose a simple quantum error-correcting code for the detected amplitude damping channel. The code requires only two qubits. We implement the encoding, the channel, and the recovery on an optical platform, the IBM Q System, and a nuclear magnetic resonance system. For all of these systems, the error correction advantage appears when the damping rate exceeds some threshold. We compare the features of these quantum information processing systems used and demonstrate the advantage of quantum error correction on current quantum computing platforms. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2001.07998v1-abstract-full').style.display = 'none'; document.getElementById('2001.07998v1-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 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">Comments:</span> <span class="has-text-grey-dark mathjax">26 pages, 9 figures, 4 tables</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Science Bulletin, 2020 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1912.05246">arXiv:1912.05246</a> <span> [<a href="https://arxiv.org/pdf/1912.05246">pdf</a>, <a href="https://arxiv.org/ps/1912.05246">ps</a>, <a href="https://arxiv.org/format/1912.05246">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/10.1103/PhysRevA.102.053713">10.1103/PhysRevA.102.053713 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Photon blockade in a bi-mode nonlinear nano-cavity embedded with a quantum-dot </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Liang%2C+X">Xinyun Liang</a>, <a href="/search/quant-ph?searchtype=author&query=Duan%2C+Z">Zhenglu Duan</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Q">Qin Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Guan%2C+S">Shengguo Guan</a>, <a href="/search/quant-ph?searchtype=author&query=Xie%2C+M">Min Xie</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+C">Cunjin Liu</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="1912.05246v1-abstract-short" style="display: inline;"> We study the interaction between a quantum-dot and a bi-mode micro/nano-optical cavity composed of second-order nonlinear materials. Compared with the Jaynes-Cummings (J-C) model, except for a coherent weak driving field, a strong pump light illuminates the two-mode optical cavity. Analytical results indicate that the model exhibits abundant non-classical optical phenomena, such as conventional ph… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1912.05246v1-abstract-full').style.display = 'inline'; document.getElementById('1912.05246v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1912.05246v1-abstract-full" style="display: none;"> We study the interaction between a quantum-dot and a bi-mode micro/nano-optical cavity composed of second-order nonlinear materials. Compared with the Jaynes-Cummings (J-C) model, except for a coherent weak driving field, a strong pump light illuminates the two-mode optical cavity. Analytical results indicate that the model exhibits abundant non-classical optical phenomena, such as conventional photon blockade induced by the nonlinear interaction between polaritons. It constitutes unconventional photon blockade induced by quantum interference due to parametric driving. We compare the photon statistical properties and average photon number of the proposed model, J-C model, and double-mode driven optical cavity under the same parameters and the proposed model can obtain stronger antibunching photons and higher average photon number. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1912.05246v1-abstract-full').style.display = 'none'; document.getElementById('1912.05246v1-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> 11 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">Journal ref:</span> Phys. Rev. A 102, 053713 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1912.02818">arXiv:1912.02818</a> <span> [<a href="https://arxiv.org/pdf/1912.02818">pdf</a>, <a href="https://arxiv.org/format/1912.02818">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/10.1038/s41567-020-1035-1">10.1038/s41567-020-1035-1 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Observation of energy resolved many-body localization </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Q">Qiujiang Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Cheng%2C+C">Chen Cheng</a>, <a href="/search/quant-ph?searchtype=author&query=Sun%2C+Z">Zheng-Hang Sun</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+Z">Zixuan Song</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+H">Hekang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zhen Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Ren%2C+W">Wenhui Ren</a>, <a href="/search/quant-ph?searchtype=author&query=Dong%2C+H">Hang Dong</a>, <a href="/search/quant-ph?searchtype=author&query=Zheng%2C+D">Dongning Zheng</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Y">Yu-Ran Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Mondaini%2C+R">Rubem Mondaini</a>, <a href="/search/quant-ph?searchtype=author&query=Fan%2C+H">Heng Fan</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+H">H. Wang</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="1912.02818v1-abstract-short" style="display: inline;"> Many-body localization (MBL) describes a quantum phase where an isolated interacting system subject to sufficient disorder displays non-ergodic behavior, evading thermal equilibrium that occurs under its own dynamics. Previously, the thermalization-MBL transition has been largely characterized with the growth of disorder. Here, we explore a new axis, reporting on an energy resolved MBL transition… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1912.02818v1-abstract-full').style.display = 'inline'; document.getElementById('1912.02818v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1912.02818v1-abstract-full" style="display: none;"> Many-body localization (MBL) describes a quantum phase where an isolated interacting system subject to sufficient disorder displays non-ergodic behavior, evading thermal equilibrium that occurs under its own dynamics. Previously, the thermalization-MBL transition has been largely characterized with the growth of disorder. Here, we explore a new axis, reporting on an energy resolved MBL transition using a 19-qubit programmable superconducting processor, which enables precise control and flexibility of both disorder strength and initial state preparations. We observe that the onset of localization occurs at different disorder strengths, with distinguishable energy scales, by measuring time-evolved observables and many-body wavefunctions related quantities. Our results open avenues for the experimental exploration of many-body mobility edges in MBL systems, whose existence is widely debated due to system size finiteness, and where exact simulations in classical computers become unfeasible. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1912.02818v1-abstract-full').style.display = 'none'; document.getElementById('1912.02818v1-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 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">9 pages, 5 figures + supplementary information</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1907.13468">arXiv:1907.13468</a> <span> [<a href="https://arxiv.org/pdf/1907.13468">pdf</a>, <a href="https://arxiv.org/format/1907.13468">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/10.1103/PhysRevLett.124.013601">10.1103/PhysRevLett.124.013601 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Generation and controllable switching of superradiant and subradiant states in a 10-qubit superconducting circuit </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zhen Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+H">Hekang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Feng%2C+W">Wei Feng</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+X">Xiaohui Song</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+C">Chao Song</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+W">Wuxin Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Q">Qiujiang Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+X">Xu Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Dong%2C+H">Hang Dong</a>, <a href="/search/quant-ph?searchtype=author&query=Zheng%2C+D">Dongning Zheng</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+H">H. Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+D">Da-Wei Wang</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="1907.13468v1-abstract-short" style="display: inline;"> Superradiance and subradiance concerning enhanced and inhibited collective radiation of an ensemble of atoms have been a central topic in quantum optics. However, precise generation and control of these states remain challenging. Here we deterministically generate up to 10-qubit superradiant and 8-qubit subradiant states, each containing a single excitation, in a superconducting quantum circuit wi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1907.13468v1-abstract-full').style.display = 'inline'; document.getElementById('1907.13468v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1907.13468v1-abstract-full" style="display: none;"> Superradiance and subradiance concerning enhanced and inhibited collective radiation of an ensemble of atoms have been a central topic in quantum optics. However, precise generation and control of these states remain challenging. Here we deterministically generate up to 10-qubit superradiant and 8-qubit subradiant states, each containing a single excitation, in a superconducting quantum circuit with multiple qubits interconnected by a cavity resonator. The $\sqrt{N}$-scaling enhancement of the coupling strength between the superradiant states and the cavity is validated. By applying appropriate phase gate on each qubit, we are able to switch the single collective excitation between superradiant and subradiant states. While the subradiant states containing a single excitation are forbidden from emitting photons, we demonstrate that they can still absorb photons from the resonator. However, for even number of qubits, a singlet state with half of the qubits being excited can neither emit nor absorb photons, which is verified with 4 qubits. This study is a step forward in coherent control of collective radiation and has promising applications in quantum information processing. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1907.13468v1-abstract-full').style.display = 'none'; document.getElementById('1907.13468v1-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 July, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 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">5 pages, 4 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. 124, 013601 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1905.00320">arXiv:1905.00320</a> <span> [<a href="https://arxiv.org/pdf/1905.00320">pdf</a>, <a href="https://arxiv.org/ps/1905.00320">ps</a>, <a href="https://arxiv.org/format/1905.00320">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.aay0600">10.1126/science.aay0600 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Observation of multi-component atomic Schr枚dinger cat states of up to 20 qubits </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Song%2C+C">Chao Song</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+K">Kai Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+H">Hekang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Y">Yuran Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+X">Xu Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+W">Wuxin Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Q">Qiujiang Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zhen Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Ren%2C+W">Wenhui Ren</a>, <a href="/search/quant-ph?searchtype=author&query=Hao%2C+J">Jie Hao</a>, <a href="/search/quant-ph?searchtype=author&query=Feng%2C+H">Hui Feng</a>, <a href="/search/quant-ph?searchtype=author&query=Fan%2C+H">Heng Fan</a>, <a href="/search/quant-ph?searchtype=author&query=Zheng%2C+D">Dongning Zheng</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+D">Dawei Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+H">H. Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+S">Shiyao Zhu</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="1905.00320v1-abstract-short" style="display: inline;"> We report on deterministic generation of 18-qubit genuinely entangled Greenberger-Horne-Zeilinger (GHZ) state and multi-component atomic Schr枚dinger cat states of up to 20 qubits on a quantum processor, which features 20 superconducting qubits interconnected by a bus resonator. By engineering a one-axis twisting Hamiltonian enabled by the resonator-mediated interactions, the system of qubits initi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1905.00320v1-abstract-full').style.display = 'inline'; document.getElementById('1905.00320v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1905.00320v1-abstract-full" style="display: none;"> We report on deterministic generation of 18-qubit genuinely entangled Greenberger-Horne-Zeilinger (GHZ) state and multi-component atomic Schr枚dinger cat states of up to 20 qubits on a quantum processor, which features 20 superconducting qubits interconnected by a bus resonator. By engineering a one-axis twisting Hamiltonian enabled by the resonator-mediated interactions, the system of qubits initialized coherently evolves to an over-squeezed, non-Gaussian regime, where atomic Schr枚dinger cat states, i.e., superpositions of atomic coherent states including GHZ state, appear at specific time intervals in excellent agreement with theory. With high controllability, we are able to take snapshots of the dynamics by plotting quasidistribution $Q$-functions of the 20-qubit atomic cat states, and globally characterize the 18-qubit GHZ state which yields a fidelity of $0.525\pm0.005$ confirming genuine eighteen-partite entanglement. Our results demonstrate the largest entanglement controllably created so far in solid state architectures, and the process of generating and detecting multipartite entanglement may promise applications in practical quantum metrology, quantum information processing and quantum computation. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1905.00320v1-abstract-full').style.display = 'none'; document.getElementById('1905.00320v1-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 May, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 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, 6 figures, 1 table including supplementary material</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Science 365, 574-577 (2019) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1811.06690">arXiv:1811.06690</a> <span> [<a href="https://arxiv.org/pdf/1811.06690">pdf</a>, <a href="https://arxiv.org/format/1811.06690">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/10.1103/PhysRevA.100.063834">10.1103/PhysRevA.100.063834 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Conventional and unconventional photon blockade effects in an atom-cavity system </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Liang%2C+X">Xinyun Liang</a>, <a href="/search/quant-ph?searchtype=author&query=Duan%2C+Z">Zhenglu Duan</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Q">Qin Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+C">Cunjin Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Guan%2C+S">Shengguo Guan</a>, <a href="/search/quant-ph?searchtype=author&query=Ren%2C+Y">Yi Ren</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="1811.06690v2-abstract-short" style="display: inline;"> A two-level system interacting with a cavity field is an important model for investigating the photon blockade (PB) effect. Most work on this topic has been based on the assumption that the atomic transition frequency is resonant with the fundamental mode frequency of the cavity. We relax this constraint and reexamine PB in a more general atom--cavity system with arbitrary atomic and cavity detuni… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1811.06690v2-abstract-full').style.display = 'inline'; document.getElementById('1811.06690v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1811.06690v2-abstract-full" style="display: none;"> A two-level system interacting with a cavity field is an important model for investigating the photon blockade (PB) effect. Most work on this topic has been based on the assumption that the atomic transition frequency is resonant with the fundamental mode frequency of the cavity. We relax this constraint and reexamine PB in a more general atom--cavity system with arbitrary atomic and cavity detunings from a driving field. The results show that when the signs of the atomic and cavity detunings are the same, PB occurs only in the strong-coupling regime, but for opposite signs of the atomic and cavity detunings, strong photon antibunching is observed in both the weak- and strong-coupling regimes and a better PB effect is achieved compared with the case when the signs are the same. More interestingly, we find that this PB arises from quantum interference for both weak and strong nonlinearities. These results deepen our understanding of the underlying mechanism of PB and may be help in the construction of single-photon sources with higher purity and better flexibility using atom--cavity systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1811.06690v2-abstract-full').style.display = 'none'; document.getElementById('1811.06690v2-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 January, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 16 November, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2018. </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, 5 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. A 100, 063834 (2019) </p> </li> </ol> <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=Guo%2C+Q&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Guo%2C+Q&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=Guo%2C+Q&start=50" class="pagination-link " aria-label="Page 2" aria-current="page">2 </a> </li> </ul> </nav> <div class="is-hidden-tablet">  <span class="help" style="display: inline-block;"><a href="https://github.com/arXiv/arxiv-search/releases">Search v0.5.6 released 2020-02-24</a>  </span> </div> </div> </main> <footer> <div class="columns is-desktop" role="navigation" aria-label="Secondary">  <div class="column"> <div class="columns"> <div class="column"> <ul 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