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<button class="button is-small is-link">Go</button> </div> </div> </form> </div> </div> <nav class="pagination is-small is-centered breathe-horizontal" role="navigation" aria-label="pagination"> <a href="" class="pagination-previous is-invisible">Previous </a> <a href="/search/?searchtype=author&query=Chen%2C+C&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Chen%2C+C&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=Chen%2C+C&start=50" class="pagination-link " aria-label="Page 2" aria-current="page">2 </a> </li> <li> <a href="/search/?searchtype=author&query=Chen%2C+C&start=100" class="pagination-link " aria-label="Page 3" aria-current="page">3 </a> </li> <li> <a href="/search/?searchtype=author&query=Chen%2C+C&start=150" class="pagination-link " aria-label="Page 4" aria-current="page">4 </a> </li> <li> <a href="/search/?searchtype=author&query=Chen%2C+C&start=200" class="pagination-link " aria-label="Page 5" aria-current="page">5 </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/2411.17726">arXiv:2411.17726</a> <span> [<a href="https://arxiv.org/pdf/2411.17726">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Information Theory">cs.IT</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Machine Learning">cs.LG</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Neural and Evolutionary Computing">cs.NE</span> </div> </div> <p class="title is-5 mathjax"> EQNN: Enhanced Quantum Neural Network </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chen%2C+A+C+H">Abel C. H. Chen</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="2411.17726v1-abstract-short" style="display: inline;"> With the maturation of quantum computing technology, research has gradually shifted towards exploring its applications. Alongside the rise of artificial intelligence, various machine learning methods have been developed into quantum circuits and algorithms. Among them, Quantum Neural Networks (QNNs) can map inputs to quantum circuits through Feature Maps (FMs) and adjust parameter values via varia… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.17726v1-abstract-full').style.display = 'inline'; document.getElementById('2411.17726v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.17726v1-abstract-full" style="display: none;"> With the maturation of quantum computing technology, research has gradually shifted towards exploring its applications. Alongside the rise of artificial intelligence, various machine learning methods have been developed into quantum circuits and algorithms. Among them, Quantum Neural Networks (QNNs) can map inputs to quantum circuits through Feature Maps (FMs) and adjust parameter values via variational models, making them applicable in regression and classification tasks. However, designing a FM that is suitable for a given application problem is a significant challenge. In light of this, this study proposes an Enhanced Quantum Neural Network (EQNN), which includes an Enhanced Feature Map (EFM) designed in this research. This EFM effectively maps input variables to a value range more suitable for quantum computing, serving as the input to the variational model to improve accuracy. In the experimental environment, this study uses mobile data usage prediction as a case study, recommending appropriate rate plans based on users' mobile data usage. The proposed EQNN is compared with current mainstream QNNs, and experimental results show that the EQNN achieves higher accuracy with fewer quantum logic gates and converges to the optimal solution faster under different optimization algorithms. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.17726v1-abstract-full').style.display = 'none'; document.getElementById('2411.17726v1-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 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">in Chinese language</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.16830">arXiv:2411.16830</a> <span> [<a href="https://arxiv.org/pdf/2411.16830">pdf</a>, <a href="https://arxiv.org/format/2411.16830">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="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</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"> Cavity-Quantum Electrodynamics with Moir茅 Flatband Photonic Crystals </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Y">Yu-Tong Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Ye%2C+Q">Qi-Hang Ye</a>, <a href="/search/quant-ph?searchtype=author&query=Yan%2C+J">Jun-Yong Yan</a>, <a href="/search/quant-ph?searchtype=author&query=Qiao%2C+Y">Yufei Qiao</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Chen Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Cheng%2C+X">Xiao-Tian Cheng</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+C">Chen-Hui Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Z">Zi-Jian Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+C">Cheng-Nian Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Meng%2C+Y">Yun Meng</a>, <a href="/search/quant-ph?searchtype=author&query=Zou%2C+K">Kai Zou</a>, <a href="/search/quant-ph?searchtype=author&query=Zhan%2C+W">Wen-Kang Zhan</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+C">Chao Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Hu%2C+X">Xiaolong Hu</a>, <a href="/search/quant-ph?searchtype=author&query=Tee%2C+C+A+T+H">Clarence Augustine T H Tee</a>, <a href="/search/quant-ph?searchtype=author&query=Sha%2C+W+E+I">Wei E. I. Sha</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Z">Zhixiang Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+H">Huiyun Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Jin%2C+C">Chao-Yuan Jin</a>, <a href="/search/quant-ph?searchtype=author&query=Ying%2C+L">Lei Ying</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+F">Feng 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="2411.16830v1-abstract-short" style="display: inline;"> Quantum emitters are a key component in photonic quantum technologies. Enhancing their single-photon emission by engineering the photonic environment using cavities can significantly improve the overall efficiency in quantum information processing. However, this enhancement is often constrained by the need for precise nanoscale control over the emitter's position within micro- or nano-cavities. In… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.16830v1-abstract-full').style.display = 'inline'; document.getElementById('2411.16830v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.16830v1-abstract-full" style="display: none;"> Quantum emitters are a key component in photonic quantum technologies. Enhancing their single-photon emission by engineering the photonic environment using cavities can significantly improve the overall efficiency in quantum information processing. However, this enhancement is often constrained by the need for precise nanoscale control over the emitter's position within micro- or nano-cavities. Inspired by the fascinating physics of moir茅 patterns, we present an approach to strongly modify the spontaneous emission rate of a quantum emitter using a finely designed multilayer moir茅 photonic crystal with a robust isolated-flatband dispersion. Theoretical analysis reveals that, due to its nearly infinite photonic density of states, the moir茅 cavity can simultaneously achieve a high Purcell factor and exhibit large tolerance over the emitter's position. We experimentally demonstrate the coupling between this moir茅 cavity and a quantum dot through the cavity-determined polarization of the dot's emission. The radiative lifetime of the quantum dot can be tuned by a factor of 40, ranging from 42 ps to 1692 ps, which is attributed to strong Purcell enhancement and Purcell inhibition effects. Our findings pave the way for moir茅 flatband cavity-enhanced quantum light sources, quantum optical switches, and quantum nodes for quantum internet applications. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.16830v1-abstract-full').style.display = 'none'; document.getElementById('2411.16830v1-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 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.11822">arXiv:2411.11822</a> <span> [<a href="https://arxiv.org/pdf/2411.11822">pdf</a>, <a href="https://arxiv.org/format/2411.11822">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"> Logical computation demonstrated with a neutral atom quantum processor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Reichardt%2C+B+W">Ben W. Reichardt</a>, <a href="/search/quant-ph?searchtype=author&query=Paetznick%2C+A">Adam Paetznick</a>, <a href="/search/quant-ph?searchtype=author&query=Aasen%2C+D">David Aasen</a>, <a href="/search/quant-ph?searchtype=author&query=Basov%2C+I">Ivan Basov</a>, <a href="/search/quant-ph?searchtype=author&query=Bello-Rivas%2C+J+M">Juan M. Bello-Rivas</a>, <a href="/search/quant-ph?searchtype=author&query=Bonderson%2C+P">Parsa Bonderson</a>, <a href="/search/quant-ph?searchtype=author&query=Chao%2C+R">Rui Chao</a>, <a href="/search/quant-ph?searchtype=author&query=van+Dam%2C+W">Wim van Dam</a>, <a href="/search/quant-ph?searchtype=author&query=Hastings%2C+M+B">Matthew B. Hastings</a>, <a href="/search/quant-ph?searchtype=author&query=Paz%2C+A">Andres Paz</a>, <a href="/search/quant-ph?searchtype=author&query=da+Silva%2C+M+P">Marcus P. da Silva</a>, <a href="/search/quant-ph?searchtype=author&query=Sundaram%2C+A">Aarthi Sundaram</a>, <a href="/search/quant-ph?searchtype=author&query=Svore%2C+K+M">Krysta M. Svore</a>, <a href="/search/quant-ph?searchtype=author&query=Vaschillo%2C+A">Alexander Vaschillo</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zhenghan Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zanner%2C+M">Matt Zanner</a>, <a href="/search/quant-ph?searchtype=author&query=Cairncross%2C+W+B">William B. Cairncross</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Cheng-An Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Crow%2C+D">Daniel Crow</a>, <a href="/search/quant-ph?searchtype=author&query=Kim%2C+H">Hyosub Kim</a>, <a href="/search/quant-ph?searchtype=author&query=Kindem%2C+J+M">Jonathan M. Kindem</a>, <a href="/search/quant-ph?searchtype=author&query=King%2C+J">Jonathan King</a>, <a href="/search/quant-ph?searchtype=author&query=McDonald%2C+M">Michael McDonald</a>, <a href="/search/quant-ph?searchtype=author&query=Norcia%2C+M+A">Matthew A. Norcia</a>, <a href="/search/quant-ph?searchtype=author&query=Ryou%2C+A">Albert Ryou</a> , et al. (46 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="2411.11822v2-abstract-short" style="display: inline;"> Transitioning from quantum computation on physical qubits to quantum computation on encoded, logical qubits can improve the error rate of operations, and will be essential for realizing valuable quantum computational advantages. Using a neutral atom quantum processor with 256 qubits, each an individual Ytterbium atom, we demonstrate the entanglement of 24 logical qubits using the distance-two [[4,… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.11822v2-abstract-full').style.display = 'inline'; document.getElementById('2411.11822v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.11822v2-abstract-full" style="display: none;"> Transitioning from quantum computation on physical qubits to quantum computation on encoded, logical qubits can improve the error rate of operations, and will be essential for realizing valuable quantum computational advantages. Using a neutral atom quantum processor with 256 qubits, each an individual Ytterbium atom, we demonstrate the entanglement of 24 logical qubits using the distance-two [[4,2,2]] code, simultaneously detecting errors and correcting for lost qubits. We also implement the Bernstein-Vazirani algorithm with up to 28 logical qubits encoded in the [[4,1,2]] code, showing better-than-physical error rates. We demonstrate fault-tolerant quantum computation in our approach, guided by the proposal of Gottesman (2016), by performing repeated loss correction for both structured and random circuits encoded in the [[4,2,2]] code. Finally, since distance-two codes can correct qubit loss, but not other errors, we show repeated loss and error correction using the distance-three [[9,1,3]] Bacon-Shor code. These results begin to clear a path for achieving scientific quantum advantage with a programmable neutral atom quantum processor. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.11822v2-abstract-full').style.display = 'none'; document.getElementById('2411.11822v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 19 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 18 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">17 pages, 16 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/2411.11708">arXiv:2411.11708</a> <span> [<a href="https://arxiv.org/pdf/2411.11708">pdf</a>, <a href="https://arxiv.org/format/2411.11708">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"> High-fidelity universal gates in the $^{171}$Yb ground state nuclear spin qubit </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Muniz%2C+J+A">J. A. Muniz</a>, <a href="/search/quant-ph?searchtype=author&query=Stone%2C+M">M. Stone</a>, <a href="/search/quant-ph?searchtype=author&query=Stack%2C+D+T">D. T. Stack</a>, <a href="/search/quant-ph?searchtype=author&query=Jaffe%2C+M">M. Jaffe</a>, <a href="/search/quant-ph?searchtype=author&query=Kindem%2C+J+M">J. M. Kindem</a>, <a href="/search/quant-ph?searchtype=author&query=Wadleigh%2C+L">L. Wadleigh</a>, <a href="/search/quant-ph?searchtype=author&query=Zalys-Geller%2C+E">E. Zalys-Geller</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+X">X. Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C+-">C. -A. Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Norcia%2C+M+A">M. A. Norcia</a>, <a href="/search/quant-ph?searchtype=author&query=Epstein%2C+J">J. Epstein</a>, <a href="/search/quant-ph?searchtype=author&query=Halperin%2C+E">E. Halperin</a>, <a href="/search/quant-ph?searchtype=author&query=Hummel%2C+F">F. Hummel</a>, <a href="/search/quant-ph?searchtype=author&query=Wilkason%2C+T">T. Wilkason</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+M">M. Li</a>, <a href="/search/quant-ph?searchtype=author&query=Barnes%2C+K">K. Barnes</a>, <a href="/search/quant-ph?searchtype=author&query=Battaglino%2C+P">P. Battaglino</a>, <a href="/search/quant-ph?searchtype=author&query=Bohdanowicz%2C+T+C">T. C. Bohdanowicz</a>, <a href="/search/quant-ph?searchtype=author&query=Booth%2C+G">G. Booth</a>, <a href="/search/quant-ph?searchtype=author&query=Brown%2C+A">A. Brown</a>, <a href="/search/quant-ph?searchtype=author&query=Brown%2C+M+O">M. O. Brown</a>, <a href="/search/quant-ph?searchtype=author&query=Cairncross%2C+W+B">W. B. Cairncross</a>, <a href="/search/quant-ph?searchtype=author&query=Cassella%2C+K">K. Cassella</a>, <a href="/search/quant-ph?searchtype=author&query=Coxe%2C+R">R. Coxe</a>, <a href="/search/quant-ph?searchtype=author&query=Crow%2C+D">D. Crow</a> , et al. (28 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2411.11708v1-abstract-short" style="display: inline;"> Arrays of optically trapped neutral atoms are a promising architecture for the realization of quantum computers. In order to run increasingly complex algorithms, it is advantageous to demonstrate high-fidelity and flexible gates between long-lived and highly coherent qubit states. In this work, we demonstrate a universal high-fidelity gate-set with individually controlled and parallel application… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.11708v1-abstract-full').style.display = 'inline'; document.getElementById('2411.11708v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.11708v1-abstract-full" style="display: none;"> Arrays of optically trapped neutral atoms are a promising architecture for the realization of quantum computers. In order to run increasingly complex algorithms, it is advantageous to demonstrate high-fidelity and flexible gates between long-lived and highly coherent qubit states. In this work, we demonstrate a universal high-fidelity gate-set with individually controlled and parallel application of single-qubit gates and two-qubit gates operating on the ground-state nuclear spin qubit in arrays of tweezer-trapped $^{171}$Yb atoms. We utilize the long lifetime, flexible control, and high physical fidelity of our system to characterize native gates using single and two-qubit Clifford and symmetric subspace randomized benchmarking circuits with more than 200 CZ gates applied to one or two pairs of atoms. We measure our two-qubit entangling gate fidelity to be 99.72(3)% (99.40(3)%) with (without) post-selection. In addition, we introduce a simple and optimized method for calibration of multi-parameter quantum gates. These results represent important milestones towards executing complex and general quantum computation with neutral atoms. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.11708v1-abstract-full').style.display = 'none'; document.getElementById('2411.11708v1-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 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.02578">arXiv:2411.02578</a> <span> [<a href="https://arxiv.org/pdf/2411.02578">pdf</a>, <a href="https://arxiv.org/ps/2411.02578">ps</a>, <a href="https://arxiv.org/format/2411.02578">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"> Optimizing random local Hamiltonians by dissipation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Basso%2C+J">Joao Basso</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Chi-Fang Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Dalzell%2C+A+M">Alexander M. Dalzell</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="2411.02578v1-abstract-short" style="display: inline;"> A central challenge in quantum simulation is to prepare low-energy states of strongly interacting many-body systems. In this work, we study the problem of preparing a quantum state that optimizes a random all-to-all, sparse or dense, spin or fermionic $k$-local Hamiltonian. We prove that a simplified quantum Gibbs sampling algorithm achieves a $惟(\frac{1}{k})$-fraction approximation of the optimum… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.02578v1-abstract-full').style.display = 'inline'; document.getElementById('2411.02578v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.02578v1-abstract-full" style="display: none;"> A central challenge in quantum simulation is to prepare low-energy states of strongly interacting many-body systems. In this work, we study the problem of preparing a quantum state that optimizes a random all-to-all, sparse or dense, spin or fermionic $k$-local Hamiltonian. We prove that a simplified quantum Gibbs sampling algorithm achieves a $惟(\frac{1}{k})$-fraction approximation of the optimum, giving an exponential improvement on the $k$-dependence over the prior best (both classical and quantum) algorithmic guarantees. Combined with the circuit lower bound for such states, our results suggest that finding low-energy states for sparsified (quasi)local spin and fermionic models is quantumly easy but classically nontrivial. This further indicates that quantum Gibbs sampling may be a suitable metaheuristic for optimization problems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.02578v1-abstract-full').style.display = 'none'; document.getElementById('2411.02578v1-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 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">51 pages</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.21424">arXiv:2410.21424</a> <span> [<a href="https://arxiv.org/pdf/2410.21424">pdf</a>, <a href="https://arxiv.org/format/2410.21424">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="Quantum Gases">cond-mat.quant-gas</span> </div> </div> <p class="title is-5 mathjax"> Spin-1 Haldane phase in a chain of Rydberg atoms </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=M%C3%B6gerle%2C+J">J. M枚gerle</a>, <a href="/search/quant-ph?searchtype=author&query=Brechtelsbauer%2C+K">K. Brechtelsbauer</a>, <a href="/search/quant-ph?searchtype=author&query=Gea-Caballero%2C+A+T">A. T. Gea-Caballero</a>, <a href="/search/quant-ph?searchtype=author&query=Prior%2C+J">J. Prior</a>, <a href="/search/quant-ph?searchtype=author&query=Emperauger%2C+G">G. Emperauger</a>, <a href="/search/quant-ph?searchtype=author&query=Bornet%2C+G">G. Bornet</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">C. Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Lahaye%2C+T">T. Lahaye</a>, <a href="/search/quant-ph?searchtype=author&query=Browaeys%2C+A">A. Browaeys</a>, <a href="/search/quant-ph?searchtype=author&query=B%C3%BCchler%2C+H+P">H. P. B眉chler</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="2410.21424v1-abstract-short" style="display: inline;"> We present a protocol to implement a spin-1 chain in Rydberg systems using three Rydberg states close to a F枚rster resonance. In addition to dipole-dipole interactions, strong van der Waals interactions naturally appear due to the presence of the F枚rster resonance and give rise to a highly tunable Hamiltonian. The resulting phase diagram is studied using the infinite density-matrix renormalization… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.21424v1-abstract-full').style.display = 'inline'; document.getElementById('2410.21424v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.21424v1-abstract-full" style="display: none;"> We present a protocol to implement a spin-1 chain in Rydberg systems using three Rydberg states close to a F枚rster resonance. In addition to dipole-dipole interactions, strong van der Waals interactions naturally appear due to the presence of the F枚rster resonance and give rise to a highly tunable Hamiltonian. The resulting phase diagram is studied using the infinite density-matrix renormalization group and reveals a highly robust Haldane phase -- a prime example of a symmetry protected topological phase. We find experimentally accessible parameters to probe the Haldane phase in current Rydberg systems, and demonstrate an efficient adiabatic preparation scheme. This paves the way to probe the remarkable properties of spin fractionalization in the Haldane phase. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.21424v1-abstract-full').style.display = 'none'; document.getElementById('2410.21424v1-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 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">11 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/2410.15041">arXiv:2410.15041</a> <span> [<a href="https://arxiv.org/pdf/2410.15041">pdf</a>, <a href="https://arxiv.org/format/2410.15041">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"> High-precision pulse calibration of tunable couplers for high-fidelity two-qubit gates in superconducting quantum processors </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+T">Tian-Ming Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+J">Jia-Chi Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+B">Bing-Jie Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+K">Kaixuan Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+H">Hao-Tian Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Xiao%2C+Y">Yong-Xi Xiao</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+C">Cheng-Lin Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Liang%2C+G">Gui-Han Liang</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Chi-Tong Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+Y">Yu Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+H">Hao Li</a>, <a href="/search/quant-ph?searchtype=author&query=Bao%2C+Z">Zhen-Ting Bao</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+K">Kui Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+Y">Yueshan Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+L">Li Li</a>, <a href="/search/quant-ph?searchtype=author&query=He%2C+Y">Yang He</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+Z">Zheng-He Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Yu%2C+Y">Yi-Han Yu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+S">Si-Yun Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+Y">Yan-Jun Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+X">Xiaohui Song</a>, <a href="/search/quant-ph?searchtype=author&query=Zheng%2C+D">Dongning Zheng</a>, <a href="/search/quant-ph?searchtype=author&query=Xiang%2C+Z">Zhong-Cheng Xiang</a>, <a href="/search/quant-ph?searchtype=author&query=Shi%2C+Y">Yun-Hao Shi</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+K">Kai Xu</a> , et al. (1 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2410.15041v1-abstract-short" style="display: inline;"> For superconducting quantum processors, stable high-fidelity two-qubit operations depend on precise flux control of the tunable coupler. However, the pulse distortion poses a significant challenge to the control precision. Current calibration methods, which often rely on microwave crosstalk or additional readout resonators for coupler excitation and readout, tend to be cumbersome and inefficient,… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.15041v1-abstract-full').style.display = 'inline'; document.getElementById('2410.15041v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.15041v1-abstract-full" style="display: none;"> For superconducting quantum processors, stable high-fidelity two-qubit operations depend on precise flux control of the tunable coupler. However, the pulse distortion poses a significant challenge to the control precision. Current calibration methods, which often rely on microwave crosstalk or additional readout resonators for coupler excitation and readout, tend to be cumbersome and inefficient, especially when couplers only have flux control. Here, we introduce and experimentally validate a novel pulse calibration scheme that exploits the strong coupling between qubits and couplers, eliminating the need for extra coupler readout and excitation. Our method directly measures the short-time and long-time step responses of the coupler flux pulse transient, enabling us to apply predistortion to subsequent signals using fast Fourier transformation and deconvolution. This approach not only simplifies the calibration process but also significantly improves the precision and stability of the flux control. We demonstrate the efficacy of our method through the implementation of diabatic CZ and iSWAP gates with fidelities of $99.61\pm0.04\%$ and $99.82\pm0.02\%$, respectively, as well as a series of diabatic CPhase gates with high fidelities characterized by cross-entropy benchmarking. The consistency and robustness of our technique are further validated by the reduction in pulse distortion and phase error observed across multilayer CZ gates. These results underscore the potential of our calibration and predistortion method to enhance the performance of two-qubit gates in superconducting quantum processors. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.15041v1-abstract-full').style.display = 'none'; document.getElementById('2410.15041v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 19 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">16 pages, 11 figures, 7 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/2409.13025">arXiv:2409.13025</a> <span> [<a href="https://arxiv.org/pdf/2409.13025">pdf</a>, <a href="https://arxiv.org/format/2409.13025">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"> Hardware-efficient quantum error correction using concatenated bosonic qubits </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Putterman%2C+H">Harald Putterman</a>, <a href="/search/quant-ph?searchtype=author&query=Noh%2C+K">Kyungjoo Noh</a>, <a href="/search/quant-ph?searchtype=author&query=Hann%2C+C+T">Connor T. Hann</a>, <a href="/search/quant-ph?searchtype=author&query=MacCabe%2C+G+S">Gregory S. MacCabe</a>, <a href="/search/quant-ph?searchtype=author&query=Aghaeimeibodi%2C+S">Shahriar Aghaeimeibodi</a>, <a href="/search/quant-ph?searchtype=author&query=Patel%2C+R+N">Rishi N. Patel</a>, <a href="/search/quant-ph?searchtype=author&query=Lee%2C+M">Menyoung Lee</a>, <a href="/search/quant-ph?searchtype=author&query=Jones%2C+W+M">William M. Jones</a>, <a href="/search/quant-ph?searchtype=author&query=Moradinejad%2C+H">Hesam Moradinejad</a>, <a href="/search/quant-ph?searchtype=author&query=Rodriguez%2C+R">Roberto Rodriguez</a>, <a href="/search/quant-ph?searchtype=author&query=Mahuli%2C+N">Neha Mahuli</a>, <a href="/search/quant-ph?searchtype=author&query=Rose%2C+J">Jefferson Rose</a>, <a href="/search/quant-ph?searchtype=author&query=Owens%2C+J+C">John Clai Owens</a>, <a href="/search/quant-ph?searchtype=author&query=Levine%2C+H">Harry Levine</a>, <a href="/search/quant-ph?searchtype=author&query=Rosenfeld%2C+E">Emma Rosenfeld</a>, <a href="/search/quant-ph?searchtype=author&query=Reinhold%2C+P">Philip Reinhold</a>, <a href="/search/quant-ph?searchtype=author&query=Moncelsi%2C+L">Lorenzo Moncelsi</a>, <a href="/search/quant-ph?searchtype=author&query=Alcid%2C+J+A">Joshua Ari Alcid</a>, <a href="/search/quant-ph?searchtype=author&query=Alidoust%2C+N">Nasser Alidoust</a>, <a href="/search/quant-ph?searchtype=author&query=Arrangoiz-Arriola%2C+P">Patricio Arrangoiz-Arriola</a>, <a href="/search/quant-ph?searchtype=author&query=Barnett%2C+J">James Barnett</a>, <a href="/search/quant-ph?searchtype=author&query=Bienias%2C+P">Przemyslaw Bienias</a>, <a href="/search/quant-ph?searchtype=author&query=Carson%2C+H+A">Hugh A. Carson</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Cliff Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+L">Li Chen</a> , et al. (96 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="2409.13025v1-abstract-short" style="display: inline;"> In order to solve problems of practical importance, quantum computers will likely need to incorporate quantum error correction, where a logical qubit is redundantly encoded in many noisy physical qubits. The large physical-qubit overhead typically associated with error correction motivates the search for more hardware-efficient approaches. Here, using a microfabricated superconducting quantum circ… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.13025v1-abstract-full').style.display = 'inline'; document.getElementById('2409.13025v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.13025v1-abstract-full" style="display: none;"> In order to solve problems of practical importance, quantum computers will likely need to incorporate quantum error correction, where a logical qubit is redundantly encoded in many noisy physical qubits. The large physical-qubit overhead typically associated with error correction motivates the search for more hardware-efficient approaches. Here, using a microfabricated superconducting quantum circuit, we realize a logical qubit memory formed from the concatenation of encoded bosonic cat qubits with an outer repetition code of distance $d=5$. The bosonic cat qubits are passively protected against bit flips using a stabilizing circuit. Cat-qubit phase-flip errors are corrected by the repetition code which uses ancilla transmons for syndrome measurement. We realize a noise-biased CX gate which ensures bit-flip error suppression is maintained during error correction. We study the performance and scaling of the logical qubit memory, finding that the phase-flip correcting repetition code operates below threshold, with logical phase-flip error decreasing with code distance from $d=3$ to $d=5$. Concurrently, the logical bit-flip error is suppressed with increasing cat-qubit mean photon number. The minimum measured logical error per cycle is on average $1.75(2)\%$ for the distance-3 code sections, and $1.65(3)\%$ for the longer distance-5 code, demonstrating the effectiveness of bit-flip error suppression throughout the error correction cycle. These results, where the intrinsic error suppression of the bosonic encodings allows us to use a hardware-efficient outer error correcting code, indicate that concatenated bosonic codes are a compelling paradigm for reaching fault-tolerant quantum computation. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.13025v1-abstract-full').style.display = 'none'; document.getElementById('2409.13025v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 19 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">Comments on the manuscript welcome!</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2409.08584">arXiv:2409.08584</a> <span> [<a href="https://arxiv.org/pdf/2409.08584">pdf</a>, <a href="https://arxiv.org/format/2409.08584">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> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Machine Learning">cs.LG</span> </div> </div> <p class="title is-5 mathjax"> CompressedMediQ: Hybrid Quantum Machine Learning Pipeline for High-Dimensional Neuroimaging Data </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chen%2C+K">Kuan-Cheng Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yi-Tien Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+T">Tai-Yu Li</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+C">Chen-Yu Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+P">Po-Heng Li</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Cheng-Yu Chen</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="2409.08584v3-abstract-short" style="display: inline;"> This paper introduces CompressedMediQ, a novel hybrid quantum-classical machine learning pipeline specifically developed to address the computational challenges associated with high-dimensional multi-class neuroimaging data analysis. Standard neuroimaging datasets, such as large-scale MRI data from the Alzheimer's Disease Neuroimaging Initiative (ADNI) and Neuroimaging in Frontotemporal Dementia (… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.08584v3-abstract-full').style.display = 'inline'; document.getElementById('2409.08584v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.08584v3-abstract-full" style="display: none;"> This paper introduces CompressedMediQ, a novel hybrid quantum-classical machine learning pipeline specifically developed to address the computational challenges associated with high-dimensional multi-class neuroimaging data analysis. Standard neuroimaging datasets, such as large-scale MRI data from the Alzheimer's Disease Neuroimaging Initiative (ADNI) and Neuroimaging in Frontotemporal Dementia (NIFD), present significant hurdles due to their vast size and complexity. CompressedMediQ integrates classical high-performance computing (HPC) nodes for advanced MRI pre-processing and Convolutional Neural Network (CNN)-PCA-based feature extraction and reduction, addressing the limited-qubit availability for quantum data encoding in the NISQ (Noisy Intermediate-Scale Quantum) era. This is followed by Quantum Support Vector Machine (QSVM) classification. By utilizing quantum kernel methods, the pipeline optimizes feature mapping and classification, enhancing data separability and outperforming traditional neuroimaging analysis techniques. Experimental results highlight the pipeline's superior accuracy in dementia staging, validating the practical use of quantum machine learning in clinical diagnostics. Despite the limitations of NISQ devices, this proof-of-concept demonstrates the transformative potential of quantum-enhanced learning, paving the way for scalable and precise diagnostic tools in healthcare and signal processing. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.08584v3-abstract-full').style.display = 'none'; document.getElementById('2409.08584v3-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 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 13 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2409.07731">arXiv:2409.07731</a> <span> [<a href="https://arxiv.org/pdf/2409.07731">pdf</a>, <a href="https://arxiv.org/format/2409.07731">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"> Group delay controlled by the decoherence of a single artificial atom </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Cheng%2C+Y+-">Y. -T. Cheng</a>, <a href="/search/quant-ph?searchtype=author&query=Hsieh%2C+K+-">K. -M. Hsieh</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+B+-">B. -Y. Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Niu%2C+Z+Q">Z. Q. Niu</a>, <a href="/search/quant-ph?searchtype=author&query=Aziz%2C+F">F. Aziz</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y+-">Y. -H. Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Wen%2C+P+Y">P. Y. Wen</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+K+-">K. -T. Lin</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+Y+-">Y. -H. Lin</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+J+C">J. C. Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Kockum%2C+A+F">A. F. Kockum</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+G+-">G. -D. Lin</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+Z+-">Z. -R. Lin</a>, <a href="/search/quant-ph?searchtype=author&query=Lu%2C+Y">Y. Lu</a>, <a href="/search/quant-ph?searchtype=author&query=Hoi%2C+I+-">I. -C. Hoi</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="2409.07731v1-abstract-short" style="display: inline;"> The ability to slow down light at the single-photon level has applications in quantum information processing and other quantum technologies. We demonstrate two methods, both using just a single artificial atom, enabling dynamic control over microwave light velocities in waveguide quantum electrodynamics (waveguide QED). Our methods are based on two distinct mechanisms harnessing the balance betwee… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.07731v1-abstract-full').style.display = 'inline'; document.getElementById('2409.07731v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.07731v1-abstract-full" style="display: none;"> The ability to slow down light at the single-photon level has applications in quantum information processing and other quantum technologies. We demonstrate two methods, both using just a single artificial atom, enabling dynamic control over microwave light velocities in waveguide quantum electrodynamics (waveguide QED). Our methods are based on two distinct mechanisms harnessing the balance between radiative and non-radiative decay rates of a superconducting artificial atom in front of a mirror. In the first method, we tune the radiative decay of the atom using interference effects due to the mirror; in the second method, we pump the atom to control its non-radiative decay through the Autler--Townes effect. When the half the radiative decay rate exceeds the non-radiative decay rate, we observe positive group delay; conversely, dominance of the non-radiative decay rate results in negative group delay. Our results advance signal-processing capabilities in waveguide QED. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.07731v1-abstract-full').style.display = 'none'; document.getElementById('2409.07731v1-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 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.16146">arXiv:2408.16146</a> <span> [<a href="https://arxiv.org/pdf/2408.16146">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Superconductivity">cond-mat.supr-con</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/10.1126/sciadv.ado4875">10.1126/sciadv.ado4875 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Signatures of a Spin-Active Interface and Locally Enhanced Zeeman field in a Superconductor-Chiral Material Heterostructure </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Cliff Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Tran%2C+J">Jason Tran</a>, <a href="/search/quant-ph?searchtype=author&query=McFadden%2C+A">Anthony McFadden</a>, <a href="/search/quant-ph?searchtype=author&query=Simmonds%2C+R">Raymond Simmonds</a>, <a href="/search/quant-ph?searchtype=author&query=Saito%2C+K">Keisuke Saito</a>, <a href="/search/quant-ph?searchtype=author&query=Chu%2C+E">En-De Chu</a>, <a href="/search/quant-ph?searchtype=author&query=Morales%2C+D">Daniel Morales</a>, <a href="/search/quant-ph?searchtype=author&query=Suezaki%2C+V">Varrick Suezaki</a>, <a href="/search/quant-ph?searchtype=author&query=Hou%2C+Y">Yasen Hou</a>, <a href="/search/quant-ph?searchtype=author&query=Aumentado%2C+J">Joe Aumentado</a>, <a href="/search/quant-ph?searchtype=author&query=Lee%2C+P+A">Patrick A. Lee</a>, <a href="/search/quant-ph?searchtype=author&query=Moodera%2C+J+S">Jagadeesh S. Moodera</a>, <a href="/search/quant-ph?searchtype=author&query=Wei%2C+P">Peng Wei</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2408.16146v1-abstract-short" style="display: inline;"> A localized Zeeman field, intensified at heterostructure interfaces, could play a crucial role in a broad area including spintronics and unconventional superconductors. Conventionally, the generation of a local Zeeman field is achieved through magnetic exchange coupling with a magnetic material. However, magnetic elements often introduce defects, which could weaken or destroy superconductivity. Al… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.16146v1-abstract-full').style.display = 'inline'; document.getElementById('2408.16146v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.16146v1-abstract-full" style="display: none;"> A localized Zeeman field, intensified at heterostructure interfaces, could play a crucial role in a broad area including spintronics and unconventional superconductors. Conventionally, the generation of a local Zeeman field is achieved through magnetic exchange coupling with a magnetic material. However, magnetic elements often introduce defects, which could weaken or destroy superconductivity. Alternatively, the coupling between a superconductor with strong spin-orbit coupling and a non-magnetic chiral material could serve as a promising approach to generate a spin active interface. In this study, we leverage an interface superconductor, namely induced superconductivity in noble metal surface states, to probe the spin active interface. Our results unveil an enhanced interface Zeeman field, which selectively closes the surface superconducting gap while preserving the bulk superconducting pairing. The chiral material, i.e. trigonal tellurium, also induces Andreev bound states (ABS) exhibiting spin polarization. The field dependence of ABS manifests a substantially enhanced interface Land茅 g-factor (g_eff ~ 12), thereby corroborating the enhanced interface Zeeman energy. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.16146v1-abstract-full').style.display = 'none'; document.getElementById('2408.16146v1-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 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">27 pages, 11 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Science Advances 10, eado4875 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.15699">arXiv:2408.15699</a> <span> [<a href="https://arxiv.org/pdf/2408.15699">pdf</a>, <a href="https://arxiv.org/format/2408.15699">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"> Strongly interacting fermions are non-trivial yet non-glassy </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Anschuetz%2C+E+R">Eric R. Anschuetz</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Chi-Fang Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Kiani%2C+B+T">Bobak T. Kiani</a>, <a href="/search/quant-ph?searchtype=author&query=King%2C+R">Robbie King</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2408.15699v4-abstract-short" style="display: inline;"> Random spin systems at low temperatures are glassy and feature computational hardness in finding low-energy states. We study the random all-to-all interacting fermionic Sachdev--Ye--Kitaev (SYK) model and prove that, in contrast, (I) the low-energy states have polynomial circuit depth, yet (II) the annealed and quenched free energies agree to inverse-polynomially low temperatures, ruling out a gla… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.15699v4-abstract-full').style.display = 'inline'; document.getElementById('2408.15699v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.15699v4-abstract-full" style="display: none;"> Random spin systems at low temperatures are glassy and feature computational hardness in finding low-energy states. We study the random all-to-all interacting fermionic Sachdev--Ye--Kitaev (SYK) model and prove that, in contrast, (I) the low-energy states have polynomial circuit depth, yet (II) the annealed and quenched free energies agree to inverse-polynomially low temperatures, ruling out a glassy phase transition in this sense. These results are derived by showing that fermionic and spin systems significantly differ in their commutation index, which quantifies the non-commutativity of Hamiltonian terms. Our results suggest that low-temperature strongly interacting fermions, unlike spins, belong in a classically nontrivial yet quantumly easy phase. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.15699v4-abstract-full').style.display = 'none'; document.getElementById('2408.15699v4-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 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 28 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">New result on commutation index of k-local Paulis for k > log(n)</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.14970">arXiv:2408.14970</a> <span> [<a href="https://arxiv.org/pdf/2408.14970">pdf</a>, <a href="https://arxiv.org/format/2408.14970">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"> A little bit of self-correction </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Kastoryano%2C+M+J">Michael J. Kastoryano</a>, <a href="/search/quant-ph?searchtype=author&query=Kristensen%2C+L+B">Lasse B. Kristensen</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Chi-Fang Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Gily%C3%A9n%2C+A">Andr谩s Gily茅n</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2408.14970v1-abstract-short" style="display: inline;"> We investigate the emergence of stable subspaces in the low-temperature quantum thermal dynamics of finite spin chains. Our analysis reveals the existence of effective decoherence-free qudit subspaces, persisting for timescales exponential in $尾$. Surprisingly, the appearance of metastable subspaces is not directly related to the entanglement structure of the ground state(s). Rather, they arise fr… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.14970v1-abstract-full').style.display = 'inline'; document.getElementById('2408.14970v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.14970v1-abstract-full" style="display: none;"> We investigate the emergence of stable subspaces in the low-temperature quantum thermal dynamics of finite spin chains. Our analysis reveals the existence of effective decoherence-free qudit subspaces, persisting for timescales exponential in $尾$. Surprisingly, the appearance of metastable subspaces is not directly related to the entanglement structure of the ground state(s). Rather, they arise from symmetry relations in low-lying excited states. Despite their stability within a 'phase', practical realization of stable qubits is hindered by susceptibility to symmetry-breaking perturbations. This work highlights that there can be non-trivial quantum behavior in the thermal dynamics of noncommuting many body models, and opens the door to more extensive studies of self-correction in such systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.14970v1-abstract-full').style.display = 'none'; document.getElementById('2408.14970v1-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 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.13919">arXiv:2408.13919</a> <span> [<a href="https://arxiv.org/pdf/2408.13919">pdf</a>, <a href="https://arxiv.org/format/2408.13919">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="Neurons and Cognition">q-bio.NC</span> </div> </div> <p class="title is-5 mathjax"> Quantum Multimodal Contrastive Learning Framework </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Chi-Sheng Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Tsai%2C+A+H">Aidan Hung-Wen Tsai</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+S">Sheng-Chieh Huang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2408.13919v3-abstract-short" style="display: inline;"> In this paper, we propose a novel framework for multimodal contrastive learning utilizing a quantum encoder to integrate EEG (electroencephalogram) and image data. This groundbreaking attempt explores the integration of quantum encoders within the traditional multimodal learning framework. By leveraging the unique properties of quantum computing, our method enhances the representation learning cap… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.13919v3-abstract-full').style.display = 'inline'; document.getElementById('2408.13919v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.13919v3-abstract-full" style="display: none;"> In this paper, we propose a novel framework for multimodal contrastive learning utilizing a quantum encoder to integrate EEG (electroencephalogram) and image data. This groundbreaking attempt explores the integration of quantum encoders within the traditional multimodal learning framework. By leveraging the unique properties of quantum computing, our method enhances the representation learning capabilities, providing a robust framework for analyzing time series and visual information concurrently. We demonstrate that the quantum encoder effectively captures intricate patterns within EEG signals and image features, facilitating improved contrastive learning across modalities. This work opens new avenues for integrating quantum computing with multimodal data analysis, particularly in applications requiring simultaneous interpretation of temporal and visual data. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.13919v3-abstract-full').style.display = 'none'; document.getElementById('2408.13919v3-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 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 25 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">15 pages</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.19214">arXiv:2407.19214</a> <span> [<a href="https://arxiv.org/pdf/2407.19214">pdf</a>, <a href="https://arxiv.org/format/2407.19214">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Neurons and Cognition">q-bio.NC</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"> QEEGNet: Quantum Machine Learning for Enhanced Electroencephalography Encoding </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Chi-Sheng Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+S+Y">Samuel Yen-Chi Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Tsai%2C+A+H">Aidan Hung-Wen Tsai</a>, <a href="/search/quant-ph?searchtype=author&query=Wei%2C+C">Chun-Shu Wei</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2407.19214v2-abstract-short" style="display: inline;"> Electroencephalography (EEG) is a critical tool in neuroscience and clinical practice for monitoring and analyzing brain activity. Traditional neural network models, such as EEGNet, have achieved considerable success in decoding EEG signals but often struggle with the complexity and high dimensionality of the data. Recent advances in quantum computing present new opportunities to enhance machine l… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.19214v2-abstract-full').style.display = 'inline'; document.getElementById('2407.19214v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.19214v2-abstract-full" style="display: none;"> Electroencephalography (EEG) is a critical tool in neuroscience and clinical practice for monitoring and analyzing brain activity. Traditional neural network models, such as EEGNet, have achieved considerable success in decoding EEG signals but often struggle with the complexity and high dimensionality of the data. Recent advances in quantum computing present new opportunities to enhance machine learning models through quantum machine learning (QML) techniques. In this paper, we introduce Quantum-EEGNet (QEEGNet), a novel hybrid neural network that integrates quantum computing with the classical EEGNet architecture to improve EEG encoding and analysis, as a forward-looking approach, acknowledging that the results might not always surpass traditional methods but it shows its potential. QEEGNet incorporates quantum layers within the neural network, allowing it to capture more intricate patterns in EEG data and potentially offering computational advantages. We evaluate QEEGNet on a benchmark EEG dataset, BCI Competition IV 2a, demonstrating that it consistently outperforms traditional EEGNet on most of the subjects and other robustness to noise. Our results highlight the significant potential of quantum-enhanced neural networks in EEG analysis, suggesting new directions for both research and practical applications in the field. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.19214v2-abstract-full').style.display = 'none'; document.getElementById('2407.19214v2-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, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 27 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">7 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/2407.16983">arXiv:2407.16983</a> <span> [<a href="https://arxiv.org/pdf/2407.16983">pdf</a>, <a href="https://arxiv.org/format/2407.16983">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevApplied.22.014052">10.1103/PhysRevApplied.22.014052 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Three-Photon Polarization Entanglement of Green Light </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Lou%2C+Y">Yan-Chao Lou</a>, <a href="/search/quant-ph?searchtype=author&query=Ren%2C+Z">Zhi-Cheng Ren</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Chao Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Wan%2C+P">Pei Wan</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+W">Wen-Zheng Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+J">Jing Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Xue%2C+S">Shu-Tian Xue</a>, <a href="/search/quant-ph?searchtype=author&query=Dong%2C+B">Bo-Wen Dong</a>, <a href="/search/quant-ph?searchtype=author&query=Ding%2C+J">Jianping Ding</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+X">Xi-Lin Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+H">Hui-Tian 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="2407.16983v1-abstract-short" style="display: inline;"> Recently, great progress has been made in the entanglement of multiple photons at various wavelengths and in different degrees of freedom for optical quantum information applied in diverse scenarios. However, multi-photon entanglement in the transmission window of green light under the water has not been reported yet. Here, by combining femtosecond laser based multi-photon entanglement and entangl… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.16983v1-abstract-full').style.display = 'inline'; document.getElementById('2407.16983v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.16983v1-abstract-full" style="display: none;"> Recently, great progress has been made in the entanglement of multiple photons at various wavelengths and in different degrees of freedom for optical quantum information applied in diverse scenarios. However, multi-photon entanglement in the transmission window of green light under the water has not been reported yet. Here, by combining femtosecond laser based multi-photon entanglement and entanglement-maintaining frequency upconversion techniques, we successfully generate a green two-photon polarization-entangled Bell state and a green three-photon Greenberger-Horne-Zeilinger (GHZ) state, whose state fidelities are 0.893$\mathbf{\pm}$0.002 and 0.595$\mathbf{\pm}$0.023, respectively. Our result provides a scalable method to prepare green multi-photon entanglement, which may have wide applications in underwater quantum information. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.16983v1-abstract-full').style.display = 'none'; document.getElementById('2407.16983v1-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 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">8 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. Applied 22, 014052 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.13321">arXiv:2407.13321</a> <span> [<a href="https://arxiv.org/pdf/2407.13321">pdf</a>, <a href="https://arxiv.org/format/2407.13321">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"> Hardware-Efficient Stabilization of Entanglement via Engineered Dissipation in Superconducting Circuits </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Changling Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Tang%2C+K">Kai Tang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Y">Yuxuan Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Yi%2C+K">KangYuan Yi</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+X">Xuan Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+X">Xu Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+H">Haosheng Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+S">Song Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Y">Yuanzhen Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Yan%2C+T">Tongxing Yan</a>, <a href="/search/quant-ph?searchtype=author&query=Yu%2C+D">Dapeng Yu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2407.13321v1-abstract-short" style="display: inline;"> Generation and preservation of quantum entanglement are among the primary tasks in quantum information processing. State stabilization via quantum bath engineering offers a resource-efficient approach to achieve this objective. However, current methods for engineering dissipative channels to stabilize target entangled states often require specialized hardware designs, complicating experimental rea… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.13321v1-abstract-full').style.display = 'inline'; document.getElementById('2407.13321v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.13321v1-abstract-full" style="display: none;"> Generation and preservation of quantum entanglement are among the primary tasks in quantum information processing. State stabilization via quantum bath engineering offers a resource-efficient approach to achieve this objective. However, current methods for engineering dissipative channels to stabilize target entangled states often require specialized hardware designs, complicating experimental realization and hindering their compatibility with scalable quantum computation architectures. In this work, we propose and experimentally demonstrate a stabilization protocol readily implementable in the mainstream integrated superconducting quantum circuits. The approach utilizes a Raman process involving a resonant (or nearly resonant) superconducting qubit array and their dedicated readout resonators to effectively emerge nonlocal dissipative channels. Leveraging individual controllability of the qubits and resonators, the protocol stabilizes two-qubit Bell states with a fidelity of $90.7\%$, marking the highest reported value in solid-state platforms to date. Furthermore, by extending this strategy to include three qubits, an entangled $W$ state is achieved with a fidelity of $86.2\%$, which has not been experimentally investigated before. Notably, the protocol is of practical interest since it only utilizes existing hardware common to standard operations in the underlying superconducting circuits, thereby facilitating the exploration of many-body quantum entanglement with dissipative resources. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.13321v1-abstract-full').style.display = 'none'; document.getElementById('2407.13321v1-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 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.05762">arXiv:2407.05762</a> <span> [<a href="https://arxiv.org/pdf/2407.05762">pdf</a>, <a href="https://arxiv.org/format/2407.05762">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"> Achieving Heisenberg scaling in low-temperature quantum thermometry </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+N">Ning Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Chong Chen</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2407.05762v1-abstract-short" style="display: inline;"> We investigate correlation-enhanced low temperature quantum thermometry. Recent studies have revealed that bath-induced correlations can enhance the low-temperature estimation precision even starting from an uncorrelated state. However, a comprehensive understanding of this enhancement remains elusive. Using the Ramsey interferometry protocol, we illustrate that the estimation precision of $N$ the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.05762v1-abstract-full').style.display = 'inline'; document.getElementById('2407.05762v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.05762v1-abstract-full" style="display: none;"> We investigate correlation-enhanced low temperature quantum thermometry. Recent studies have revealed that bath-induced correlations can enhance the low-temperature estimation precision even starting from an uncorrelated state. However, a comprehensive understanding of this enhancement remains elusive. Using the Ramsey interferometry protocol, we illustrate that the estimation precision of $N$ thermometers sparsely coupled to a common low-temperature bath can achieve the Heisenberg scaling in the low-temperature regime with only a $蟺/2$ rotation of the measurement axis, in contrast to the standard Ramsey scheme. This result is based on the assumption that interthermometer correlations are induced exclusively by low-frequency noise in the common bath, a condition achievable in practical experimental scenarios. The underlying physical mechanism is clarified, revealing that the Heisenberg scaling arises from the intrinsic nature of the temperature, which is associated solely with the fluctuation of thermal noise. In contrast to the paradigm of independent thermometers, our proposed scheme demonstrates a significant enhancement in precision for low-temperature measurement, making it suitable for precisely measuring the temperature of ultracold systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.05762v1-abstract-full').style.display = 'none'; document.getElementById('2407.05762v1-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 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">7 pages, 2 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.04338">arXiv:2407.04338</a> <span> [<a href="https://arxiv.org/pdf/2407.04338">pdf</a>, <a href="https://arxiv.org/format/2407.04338">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"> Entanglement distribution based on quantum walk in arbitrary quantum networks </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chen%2C+T">Tianen Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Shang%2C+Y">Yun Shang</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Chitong Chen</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="2407.04338v1-abstract-short" style="display: inline;"> In large-scale quantum networks, distributing the multi-particle entangled state among selected nodes is crucial for realizing long-distance and complicated quantum communication. Quantum repeaters provides an efficient method to generate entanglement between distant nodes. However, it is difficult to extend quantum repeater protocols to high-dimensional quantum states in existing experiments. Her… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.04338v1-abstract-full').style.display = 'inline'; document.getElementById('2407.04338v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.04338v1-abstract-full" style="display: none;"> In large-scale quantum networks, distributing the multi-particle entangled state among selected nodes is crucial for realizing long-distance and complicated quantum communication. Quantum repeaters provides an efficient method to generate entanglement between distant nodes. However, it is difficult to extend quantum repeater protocols to high-dimensional quantum states in existing experiments. Here we develop a series of scheme for generating high-dimensional entangled states via quantum walks with multiple coins or single coin by quantum repeaters, including $d$-dimensional Bell states, multi-particle high dimensional GHZ states etc.. Furthermore, we give entanglement distribution schemes on arbitrary quantum networks according to the above theoretical framework. As applications, we construct quantum fractal networks and multiparty quantum secret sharing protocols based on $d$-dimensional GHZ states. In the end, we give the experiment implementing of various 2-party or 3-party entanglement generation schemes based on repeaters. Our work can serve as a building block for constructing larger and more complex quantum networks. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.04338v1-abstract-full').style.display = 'none'; document.getElementById('2407.04338v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2406.07478">arXiv:2406.07478</a> <span> [<a href="https://arxiv.org/pdf/2406.07478">pdf</a>, <a href="https://arxiv.org/format/2406.07478">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 Complexity">cs.CC</span> </div> </div> <p class="title is-5 mathjax"> Incompressibility and spectral gaps of random circuits </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Chi-Fang Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Haah%2C+J">Jeongwan Haah</a>, <a href="/search/quant-ph?searchtype=author&query=Haferkamp%2C+J">Jonas Haferkamp</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+Y">Yunchao Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Metger%2C+T">Tony Metger</a>, <a href="/search/quant-ph?searchtype=author&query=Tan%2C+X">Xinyu Tan</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="2406.07478v2-abstract-short" style="display: inline;"> Random reversible and quantum circuits form random walks on the alternating group $\mathrm{Alt}(2^n)$ and unitary group $\mathrm{SU}(2^n)$, respectively. Known bounds on the spectral gap for the $t$-th moment of these random walks have inverse-polynomial dependence in both $n$ and $t$. We prove that the gap for random reversible circuits is $惟(n^{-3})$ for all $t\geq 1$, and the gap for random qua… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.07478v2-abstract-full').style.display = 'inline'; document.getElementById('2406.07478v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2406.07478v2-abstract-full" style="display: none;"> Random reversible and quantum circuits form random walks on the alternating group $\mathrm{Alt}(2^n)$ and unitary group $\mathrm{SU}(2^n)$, respectively. Known bounds on the spectral gap for the $t$-th moment of these random walks have inverse-polynomial dependence in both $n$ and $t$. We prove that the gap for random reversible circuits is $惟(n^{-3})$ for all $t\geq 1$, and the gap for random quantum circuits is $惟(n^{-3})$ for $t \leq 螛(2^{n/2})$. These gaps are independent of $t$ in the respective regimes. We can further improve both gaps to $n^{-1}/\mathrm{polylog}(n, t)$ for $t\leq 2^{螛(n)}$, which is tight up to polylog factors. Our spectral gap results have a number of consequences: 1) Random reversible circuits with $\mathcal{O}(n^4 t)$ gates form multiplicative-error $t$-wise independent (even) permutations for all $t\geq 1$; for $t \leq 螛(2^{n/6.1})$, we show that $\tilde{\mathcal{O}}(n^2 t)$ gates suffice. 2) Random quantum circuits with $\mathcal{O}(n^4 t)$ gates form multiplicative-error unitary $t$-designs for $t \leq 螛(2^{n/2})$; for $t\leq 螛(2^{2n/5})$, we show that $\tilde{\mathcal{O}}(n^2t)$ gates suffice. 3) The robust quantum circuit complexity of random circuits grows linearly for an exponentially long time, proving the robust Brown--Susskind conjecture [BS18,BCHJ+21]. Our spectral gap bounds are proven by reducing random quantum circuits to a more structured walk: a modification of the ``$\mathrm{PFC}$ ensemble'' from [MPSY24] together with an expander on the alternating group due to Kassabov [Kas07a], for which we give an efficient implementation using reversible circuits. In our reduction, we approximate the structured walk with local random circuits without losing the gap, which uses tools from the study of frustration-free Hamiltonians. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.07478v2-abstract-full').style.display = 'none'; document.getElementById('2406.07478v2-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 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 11 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">80 pages, 5 figures, v2: added references and minor changes in the presentation</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2406.05007">arXiv:2406.05007</a> <span> [<a href="https://arxiv.org/pdf/2406.05007">pdf</a>, <a href="https://arxiv.org/format/2406.05007">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"> Slow and Stored Light via Electromagnetically Induced Transparency Using A $螞$-type Superconducting Artificial Atom </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chu%2C+K">Kai-I Chu</a>, <a href="/search/quant-ph?searchtype=author&query=Lu%2C+X">Xiao-Cheng Lu</a>, <a href="/search/quant-ph?searchtype=author&query=Chiang%2C+K">Kuan-Hsun Chiang</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+Y">Yen-Hsiang Lin</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Chii-Dong Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Yu%2C+I+A">Ite A. Yu</a>, <a href="/search/quant-ph?searchtype=author&query=Liao%2C+W">Wen-Te Liao</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Y">Yung-Fu Chen</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="2406.05007v1-abstract-short" style="display: inline;"> Recent progresses in Josephson-junction-based superconducting circuits have propelled quantum information processing forward. However, the lack of a metastable state in most superconducting artificial atoms hinders the development of photonic quantum memory in this platform. Here, we use a single superconducting qubit-resonator system to realize a desired $螞$-type artificial atom, and to demonstra… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.05007v1-abstract-full').style.display = 'inline'; document.getElementById('2406.05007v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2406.05007v1-abstract-full" style="display: none;"> Recent progresses in Josephson-junction-based superconducting circuits have propelled quantum information processing forward. However, the lack of a metastable state in most superconducting artificial atoms hinders the development of photonic quantum memory in this platform. Here, we use a single superconducting qubit-resonator system to realize a desired $螞$-type artificial atom, and to demonstrate slow light with a group velocity of 3.6 km/s and the microwave storage with a memory time extending to several hundred nanoseconds via electromagnetically induced transparency. Our results highlight the potential of achieving microwave quantum memory, promising substantial advancements in quantum information processing within superconducting circuits. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.05007v1-abstract-full').style.display = 'none'; document.getElementById('2406.05007v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 7 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">10 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/2406.00091">arXiv:2406.00091</a> <span> [<a href="https://arxiv.org/pdf/2406.00091">pdf</a>, <a href="https://arxiv.org/format/2406.00091">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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="Quantum Gases">cond-mat.quant-gas</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Transformer neural networks and quantum simulators: a hybrid approach for simulating strongly correlated systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Lange%2C+H">Hannah Lange</a>, <a href="/search/quant-ph?searchtype=author&query=Bornet%2C+G">Guillaume Bornet</a>, <a href="/search/quant-ph?searchtype=author&query=Emperauger%2C+G">Gabriel Emperauger</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Cheng Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Lahaye%2C+T">Thierry Lahaye</a>, <a href="/search/quant-ph?searchtype=author&query=Kienle%2C+S">Stefan Kienle</a>, <a href="/search/quant-ph?searchtype=author&query=Browaeys%2C+A">Antoine Browaeys</a>, <a href="/search/quant-ph?searchtype=author&query=Bohrdt%2C+A">Annabelle Bohrdt</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="2406.00091v1-abstract-short" style="display: inline;"> Owing to their great expressivity and versatility, neural networks have gained attention for simulating large two-dimensional quantum many-body systems. However, their expressivity comes with the cost of a challenging optimization due to the in general rugged and complicated loss landscape. Here, we present a hybrid optimization scheme for neural quantum states (NQS) that involves a data-driven pr… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.00091v1-abstract-full').style.display = 'inline'; document.getElementById('2406.00091v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2406.00091v1-abstract-full" style="display: none;"> Owing to their great expressivity and versatility, neural networks have gained attention for simulating large two-dimensional quantum many-body systems. However, their expressivity comes with the cost of a challenging optimization due to the in general rugged and complicated loss landscape. Here, we present a hybrid optimization scheme for neural quantum states (NQS) that involves a data-driven pretraining with numerical or experimental data and a second, Hamiltonian-driven optimization stage. By using both projective measurements from the computational basis as well as expectation values from other measurement configurations such as spin-spin correlations, our pretraining gives access to the sign structure of the state, yielding improved and faster convergence that is robust w.r.t. experimental imperfections and limited datasets. We apply the hybrid scheme to the ground state search for the 2D transverse field Ising model and the 2D dipolar XY model on $6\times 6$ and $10\times 10$ square lattices with a patched transformer wave function, using numerical and experimental data from a programmable Rydberg quantum simulator [Chen et al., Nature 616 (2023)], with snapshots of the quantum system obtained from the different measurement configurations, and show that the information from the second basis highly improves the performance. Our work paves the way for a reliable and efficient optimization of neural quantum states. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.00091v1-abstract-full').style.display = 'none'; document.getElementById('2406.00091v1-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> 31 May, 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">7 pages, 4 figures and supplementary material</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2405.20946">arXiv:2405.20946</a> <span> [<a href="https://arxiv.org/pdf/2405.20946">pdf</a>, <a href="https://arxiv.org/format/2405.20946">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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="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/10.1063/5.0221387">10.1063/5.0221387 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Fast characterization of multiplexed single-electron pumps with machine learning </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Schoinas%2C+N">N. Schoinas</a>, <a href="/search/quant-ph?searchtype=author&query=Rath%2C+Y">Y. Rath</a>, <a href="/search/quant-ph?searchtype=author&query=Norimoto%2C+S">S. Norimoto</a>, <a href="/search/quant-ph?searchtype=author&query=Xie%2C+W">W. Xie</a>, <a href="/search/quant-ph?searchtype=author&query=See%2C+P">P. See</a>, <a href="/search/quant-ph?searchtype=author&query=Griffiths%2C+J+P">J. P. Griffiths</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">C. Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Ritchie%2C+D+A">D. A. Ritchie</a>, <a href="/search/quant-ph?searchtype=author&query=Kataoka%2C+M">M. Kataoka</a>, <a href="/search/quant-ph?searchtype=author&query=Rossi%2C+A">A. Rossi</a>, <a href="/search/quant-ph?searchtype=author&query=Rungger%2C+I">I. Rungger</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="2405.20946v2-abstract-short" style="display: inline;"> We present an efficient machine learning based automated framework for the fast tuning of single-electron pump devices into current quantization regimes. It uses a sparse measurement approach based on an iterative active learning algorithm to take targeted measurements in the gate voltage parameter space. When compared to conventional parameter scans, our automated framework allows us to decrease… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.20946v2-abstract-full').style.display = 'inline'; document.getElementById('2405.20946v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.20946v2-abstract-full" style="display: none;"> We present an efficient machine learning based automated framework for the fast tuning of single-electron pump devices into current quantization regimes. It uses a sparse measurement approach based on an iterative active learning algorithm to take targeted measurements in the gate voltage parameter space. When compared to conventional parameter scans, our automated framework allows us to decrease the number of measurement points by about an order of magnitude. This corresponds to an eight-fold decrease in the time required to determine quantization errors, which are estimated via an exponential extrapolation of the first current plateau embedded into the algorithm. We show the robustness of the framework by characterizing 28 individual devices arranged in a GaAs/AlGaAs multiplexer array, which we use to identify a subset of devices suitable for parallel operation at communal gate voltages. The method opens up the possibility to efficiently scale the characterization of such multiplexed devices to a large number of pumps. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.20946v2-abstract-full').style.display = 'none'; document.getElementById('2405.20946v2-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 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 31 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">6 pages, 3 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Appl. Phys. Lett. 125, 124001 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2405.20322">arXiv:2405.20322</a> <span> [<a href="https://arxiv.org/pdf/2405.20322">pdf</a>, <a href="https://arxiv.org/format/2405.20322">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="Data Structures and Algorithms">cs.DS</span> </div> </div> <p class="title is-5 mathjax"> Quantum generalizations of Glauber and Metropolis dynamics </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Gily%C3%A9n%2C+A">Andr谩s Gily茅n</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Chi-Fang Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Doriguello%2C+J+F">Joao F. Doriguello</a>, <a href="/search/quant-ph?searchtype=author&query=Kastoryano%2C+M+J">Michael J. Kastoryano</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="2405.20322v1-abstract-short" style="display: inline;"> Classical Markov Chain Monte Carlo methods have been essential for simulating statistical physical systems and have proven well applicable to other systems with complex degrees of freedom. Motivated by the statistical physics origins, Chen, Kastoryano, and Gily茅n [CKG23] proposed a continuous-time quantum thermodynamic analog to Glauber dynamic that is (i) exactly detailed balanced, (ii) efficient… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.20322v1-abstract-full').style.display = 'inline'; document.getElementById('2405.20322v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.20322v1-abstract-full" style="display: none;"> Classical Markov Chain Monte Carlo methods have been essential for simulating statistical physical systems and have proven well applicable to other systems with complex degrees of freedom. Motivated by the statistical physics origins, Chen, Kastoryano, and Gily茅n [CKG23] proposed a continuous-time quantum thermodynamic analog to Glauber dynamic that is (i) exactly detailed balanced, (ii) efficiently implementable, and (iii) quasi-local for geometrically local systems. Physically, their construction gives a smooth variant of the Davies' generator derived from weak system-bath interaction. In this work, we give an efficiently implementable discrete-time quantum counterpart to Metropolis sampling that also enjoys the desirable features (i)-(iii). Also, we give an alternative highly coherent quantum generalization of detailed balanced dynamics that resembles another physically derived master equation, and propose a smooth interpolation between this and earlier constructions. We study generic properties of all constructions, including the uniqueness of the fixed-point and the locality of the resulting operators. We hope our results provide a systematic approach to the possible quantum generalizations of classical Glauber and Metropolis dynamics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.20322v1-abstract-full').style.display = 'none'; document.getElementById('2405.20322v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2405.15595">arXiv:2405.15595</a> <span> [<a href="https://arxiv.org/pdf/2405.15595">pdf</a>, <a href="https://arxiv.org/format/2405.15595">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"> Fast adiabatic preparation of multi-squeezed states by jumping along the path </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Chuan Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Lu%2C+J">Jian-Yu Lu</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+X">Xu-Yang Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zhen-Yu 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="2405.15595v1-abstract-short" style="display: inline;"> Multi-squeezed states, also known as generalized squeezed states, are valuable quantum non-Gaussian resources, because they can feature non-classical properties such as large phase-space Wigner negativities. In this work, we introduce a novel shortcuts to adiabaticity (STA) method for the fast preparation of multi-squeezed states. In contrast to previous STA methods, which rely on the use of count… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.15595v1-abstract-full').style.display = 'inline'; document.getElementById('2405.15595v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.15595v1-abstract-full" style="display: none;"> Multi-squeezed states, also known as generalized squeezed states, are valuable quantum non-Gaussian resources, because they can feature non-classical properties such as large phase-space Wigner negativities. In this work, we introduce a novel shortcuts to adiabaticity (STA) method for the fast preparation of multi-squeezed states. In contrast to previous STA methods, which rely on the use of counterdiabatic control to suppress unwanted non-adiabatic effects, our method simplifies the process and accelerates state preparation by selecting an appropriate sampling along a quantum evolution path. We demonstrate the high-fidelity and fast preparation of multi-squeezed states, as well as hybrid entangled states between a bosonic mode and a qubit. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.15595v1-abstract-full').style.display = 'none'; document.getElementById('2405.15595v1-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 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2404.16751">arXiv:2404.16751</a> <span> [<a href="https://arxiv.org/pdf/2404.16751">pdf</a>, <a href="https://arxiv.org/format/2404.16751">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="Cryptography and Security">cs.CR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mathematical Physics">math-ph</span> </div> </div> <p class="title is-5 mathjax"> Efficient unitary designs and pseudorandom unitaries from permutations </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Chi-Fang Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Bouland%2C+A">Adam Bouland</a>, <a href="/search/quant-ph?searchtype=author&query=Brand%C3%A3o%2C+F+G+S+L">Fernando G. S. L. Brand茫o</a>, <a href="/search/quant-ph?searchtype=author&query=Docter%2C+J">Jordan Docter</a>, <a href="/search/quant-ph?searchtype=author&query=Hayden%2C+P">Patrick Hayden</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+M">Michelle Xu</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="2404.16751v2-abstract-short" style="display: inline;"> In this work we give an efficient construction of unitary $k$-designs using $\tilde{O}(k\cdot poly(n))$ quantum gates, as well as an efficient construction of a parallel-secure pseudorandom unitary (PRU). Both results are obtained by giving an efficient quantum algorithm that lifts random permutations over $S(N)$ to random unitaries over $U(N)$ for $N=2^n$. In particular, we show that products of… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.16751v2-abstract-full').style.display = 'inline'; document.getElementById('2404.16751v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2404.16751v2-abstract-full" style="display: none;"> In this work we give an efficient construction of unitary $k$-designs using $\tilde{O}(k\cdot poly(n))$ quantum gates, as well as an efficient construction of a parallel-secure pseudorandom unitary (PRU). Both results are obtained by giving an efficient quantum algorithm that lifts random permutations over $S(N)$ to random unitaries over $U(N)$ for $N=2^n$. In particular, we show that products of exponentiated sums of $S(N)$ permutations with random phases approximately match the first $2^{惟(n)}$ moments of the Haar measure. By substituting either $\tilde{O}(k)$-wise independent permutations, or quantum-secure pseudorandom permutations (PRPs) in place of the random permutations, we obtain the above results. The heart of our proof is a conceptual connection between the large dimension (large-$N$) expansion in random matrix theory and the polynomial method, which allows us to prove query lower bounds at finite-$N$ by interpolating from the much simpler large-$N$ limit. The key technical step is to exhibit an orthonormal basis for irreducible representations of the partition algebra that has a low-degree large-$N$ expansion. This allows us to show that the distinguishing probability is a low-degree rational polynomial of the dimension $N$. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.16751v2-abstract-full').style.display = 'none'; document.getElementById('2404.16751v2-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 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 25 April, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 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">70 pages, 11 figures. v2: minor edits</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2404.14639">arXiv:2404.14639</a> <span> [<a href="https://arxiv.org/pdf/2404.14639">pdf</a>, <a href="https://arxiv.org/ps/2404.14639">ps</a>, <a href="https://arxiv.org/format/2404.14639">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Quantum computational advantage with constant-temperature Gibbs sampling </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Bergamaschi%2C+T">Thiago Bergamaschi</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Chi-Fang Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+Y">Yunchao 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="2404.14639v2-abstract-short" style="display: inline;"> A quantum system coupled to a bath at some fixed, finite temperature converges to its Gibbs state. This thermalization process defines a natural, physically-motivated model of quantum computation. However, whether quantum computational advantage can be achieved within this realistic physical setup has remained open, due to the challenge of finding systems that thermalize quickly, but are classical… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.14639v2-abstract-full').style.display = 'inline'; document.getElementById('2404.14639v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2404.14639v2-abstract-full" style="display: none;"> A quantum system coupled to a bath at some fixed, finite temperature converges to its Gibbs state. This thermalization process defines a natural, physically-motivated model of quantum computation. However, whether quantum computational advantage can be achieved within this realistic physical setup has remained open, due to the challenge of finding systems that thermalize quickly, but are classically intractable. Here we consider sampling from the measurement outcome distribution of quantum Gibbs states at constant temperatures, and prove that this task demonstrates quantum computational advantage. We design a family of commuting local Hamiltonians (parent Hamiltonians of shallow quantum circuits) and prove that they rapidly converge to their Gibbs states under the standard physical model of thermalization (as a continuous-time quantum Markov chain). On the other hand, we show that no polynomial time classical algorithm can sample from the measurement outcome distribution by reducing to the classical hardness of sampling from noiseless shallow quantum circuits. The key step in the reduction is constructing a fault-tolerance scheme for shallow IQP circuits against input noise. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.14639v2-abstract-full').style.display = 'none'; document.getElementById('2404.14639v2-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 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 22 April, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 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">To appear in FOCS 2024. v2: Improved main result to constant locality</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2404.14538">arXiv:2404.14538</a> <span> [<a href="https://arxiv.org/pdf/2404.14538">pdf</a>, <a href="https://arxiv.org/format/2404.14538">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="Quantum Gases">cond-mat.quant-gas</span> </div> </div> <p class="title is-5 mathjax"> Designing open quantum systems with known steady states: Davies generators and beyond </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Guo%2C+J">Jinkang Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Hart%2C+O">Oliver Hart</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Chi-Fang Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Friedman%2C+A+J">Aaron J. Friedman</a>, <a href="/search/quant-ph?searchtype=author&query=Lucas%2C+A">Andrew Lucas</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="2404.14538v1-abstract-short" style="display: inline;"> We provide a systematic framework for constructing generic models of nonequilibrium quantum dynamics with a target stationary (mixed) state. Our framework identifies (almost) all combinations of Hamiltonian and dissipative dynamics that relax to a steady state of interest, generalizing the Davies' generator for dissipative relaxation at finite temperature to nonequilibrium dynamics targeting arbit… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.14538v1-abstract-full').style.display = 'inline'; document.getElementById('2404.14538v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2404.14538v1-abstract-full" style="display: none;"> We provide a systematic framework for constructing generic models of nonequilibrium quantum dynamics with a target stationary (mixed) state. Our framework identifies (almost) all combinations of Hamiltonian and dissipative dynamics that relax to a steady state of interest, generalizing the Davies' generator for dissipative relaxation at finite temperature to nonequilibrium dynamics targeting arbitrary stationary states. We focus on Gibbs states of stabilizer Hamiltonians, identifying local Lindbladians compatible therewith by constraining the rates of dissipative and unitary processes. Moreover, given terms in the Lindbladian not compatible with the target state, our formalism identifies the operations -- including syndrome measurements and local feedback -- one must apply to correct these errors. Our methods also reveal new models of quantum dynamics: for example, we provide a "measurement-induced phase transition" where measurable two-point functions exhibit critical (power-law) scaling with distance at a critical ratio of the transverse field and rate of measurement and feedback. Time-reversal symmetry -- defined naturally within our formalism -- can be broken both in effectively classical, and intrinsically quantum, ways. Our framework provides a systematic starting point for exploring the landscape of quantum dynamical universality classes, as well as identifying new protocols for quantum error correction. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.14538v1-abstract-full').style.display = 'none'; document.getElementById('2404.14538v1-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 April, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 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">51 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/2404.07509">arXiv:2404.07509</a> <span> [<a href="https://arxiv.org/pdf/2404.07509">pdf</a>, <a href="https://arxiv.org/format/2404.07509">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.optlastec.2024.111558">10.1016/j.optlastec.2024.111558 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Multiparameter cascaded quantum interferometer </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+B">Baihong Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Q">Qi-qi Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zhuo-zhuo Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+P">Penglong Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Changhua Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Yuan%2C+B">Boxin Yuan</a>, <a href="/search/quant-ph?searchtype=author&query=Zhai%2C+Y">Yiwei Zhai</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+X">Xiaofei 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="2404.07509v3-abstract-short" style="display: inline;"> We theoretically propose a multiparameter cascaded quantum interferometer in which a two-input and two-output setup is obtained by concatenating 50:50 beam splitters with $n$ independent and adjustable time delays. A general method for deriving the coincidence probability of such an interferometer is given based on the linear transformation of the matrix of beam splitters. As examples, we analyze… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.07509v3-abstract-full').style.display = 'inline'; document.getElementById('2404.07509v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2404.07509v3-abstract-full" style="display: none;"> We theoretically propose a multiparameter cascaded quantum interferometer in which a two-input and two-output setup is obtained by concatenating 50:50 beam splitters with $n$ independent and adjustable time delays. A general method for deriving the coincidence probability of such an interferometer is given based on the linear transformation of the matrix of beam splitters. As examples, we analyze the interference characteristics of one-, two- and three-parameter cascaded quantum interferometers with different frequency correlations and input states. Some typical interferograms of such interferometers are provided to reveal richer and more complicated two-photon interference phenomena. This work offers a general theoretical framework for designing versatile quantum interferometers and provides a convenient method for deriving the coincidence probabilities involved. In principle, arbitrary two-input and two-output experimental setups can be designed with the framework. Potential applications can be found in the complete spectral characterization of two-photon states, multiparameter estimation, and quantum metrology. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.07509v3-abstract-full').style.display = 'none'; document.getElementById('2404.07509v3-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 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 11 April, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 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">16 pages, 10 figures. arXiv admin note: text overlap with arXiv:2305.13734</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Optics & Laser Technology 181 (2025) 111558 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.09095">arXiv:2403.09095</a> <span> [<a href="https://arxiv.org/pdf/2403.09095">pdf</a>, <a href="https://arxiv.org/format/2403.09095">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> </div> </div> <p class="title is-5 mathjax"> Exploring Hilbert-Space Fragmentation on a Superconducting Processor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Y">Yong-Yi Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Shi%2C+Y">Yun-Hao Shi</a>, <a href="/search/quant-ph?searchtype=author&query=Sun%2C+Z">Zheng-Hang Sun</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Chi-Tong Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zheng-An Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+K">Kui Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+H">Hao-Tian Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Ma%2C+W">Wei-Guo Ma</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Ziting Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+H">Hao Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+J">Jia-Chi Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+Y">Yu Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+C">Cheng-Lin Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+T">Tian-Ming Li</a>, <a href="/search/quant-ph?searchtype=author&query=He%2C+Y">Yang He</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+Z">Zheng-He Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+Z">Zhen-Yu Peng</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+X">Xiaohui Song</a>, <a href="/search/quant-ph?searchtype=author&query=Xue%2C+G">Guangming Xue</a>, <a href="/search/quant-ph?searchtype=author&query=Yu%2C+H">Haifeng Yu</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+K">Kaixuan Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Xiang%2C+Z">Zhongcheng Xiang</a>, <a href="/search/quant-ph?searchtype=author&query=Zheng%2C+D">Dongning Zheng</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+K">Kai Xu</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="2403.09095v1-abstract-short" style="display: inline;"> Isolated interacting quantum systems generally thermalize, yet there are several counterexamples for the breakdown of ergodicity, such as many-body localization and quantum scars. Recently, ergodicity breaking has been observed in systems subjected to linear potentials, termed Stark many-body localization. This phenomenon is closely associated with Hilbert-space fragmentation, characterized by a s… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.09095v1-abstract-full').style.display = 'inline'; document.getElementById('2403.09095v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.09095v1-abstract-full" style="display: none;"> Isolated interacting quantum systems generally thermalize, yet there are several counterexamples for the breakdown of ergodicity, such as many-body localization and quantum scars. Recently, ergodicity breaking has been observed in systems subjected to linear potentials, termed Stark many-body localization. This phenomenon is closely associated with Hilbert-space fragmentation, characterized by a strong dependence of dynamics on initial conditions. Here, we experimentally explore initial-state dependent dynamics using a ladder-type superconducting processor with up to 24 qubits, which enables precise control of the qubit frequency and initial state preparation. In systems with linear potentials, we observe distinct non-equilibrium dynamics for initial states with the same quantum numbers and energy, but with varying domain wall numbers. This distinction becomes increasingly pronounced as the system size grows, in contrast with disordered interacting systems. Our results provide convincing experimental evidence of the fragmentation in Stark systems, enriching our understanding of the weak breakdown of ergodicity. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.09095v1-abstract-full').style.display = 'none'; document.getElementById('2403.09095v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 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">main text: 7 pages, 4 figures; supplementary: 13 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/2403.02871">arXiv:2403.02871</a> <span> [<a href="https://arxiv.org/pdf/2403.02871">pdf</a>, <a href="https://arxiv.org/format/2403.02871">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="Machine Learning">cs.LG</span> </div> </div> <p class="title is-5 mathjax"> Quantum Mixed-State Self-Attention Network </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chen%2C+F">Fu Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+Q">Qinglin Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Feng%2C+L">Li Feng</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Chuangtao Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+Y">Yangbin Lin</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+J">Jianhong Lin</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="2403.02871v2-abstract-short" style="display: inline;"> The rapid advancement of quantum computing has increasingly highlighted its potential in the realm of machine learning, particularly in the context of natural language processing (NLP) tasks. Quantum machine learning (QML) leverages the unique capabilities of quantum computing to offer novel perspectives and methodologies for complex data processing and pattern recognition challenges. This paper i… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.02871v2-abstract-full').style.display = 'inline'; document.getElementById('2403.02871v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.02871v2-abstract-full" style="display: none;"> The rapid advancement of quantum computing has increasingly highlighted its potential in the realm of machine learning, particularly in the context of natural language processing (NLP) tasks. Quantum machine learning (QML) leverages the unique capabilities of quantum computing to offer novel perspectives and methodologies for complex data processing and pattern recognition challenges. This paper introduces a novel Quantum Mixed-State Attention Network (QMSAN), which integrates the principles of quantum computing with classical machine learning algorithms, especially self-attention networks, to enhance the efficiency and effectiveness in handling NLP tasks. QMSAN model employs a quantum attention mechanism based on mixed states, enabling efficient direct estimation of similarity between queries and keys within the quantum domain, leading to more effective attention weight acquisition. Additionally, we propose an innovative quantum positional encoding scheme, implemented through fixed quantum gates within the quantum circuit, to enhance the model's accuracy. Experimental validation on various datasets demonstrates that QMSAN model outperforms existing quantum and classical models in text classification, achieving significant performance improvements. QMSAN model not only significantly reduces the number of parameters but also exceeds classical self-attention networks in performance, showcasing its strong capability in data representation and information extraction. Furthermore, our study investigates the model's robustness in different quantum noise environments, showing that QMSAN possesses commendable robustness to low noise. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.02871v2-abstract-full').style.display = 'none'; document.getElementById('2403.02871v2-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 June, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 5 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/2402.18057">arXiv:2402.18057</a> <span> [<a href="https://arxiv.org/pdf/2402.18057">pdf</a>, <a href="https://arxiv.org/format/2402.18057">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> <p class="title is-5 mathjax"> A scalable cavity-based spin-photon interface in a photonic integrated circuit </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chen%2C+K+C">Kevin C. Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Christen%2C+I">Ian Christen</a>, <a href="/search/quant-ph?searchtype=author&query=Raniwala%2C+H">Hamza Raniwala</a>, <a href="/search/quant-ph?searchtype=author&query=Colangelo%2C+M">Marco Colangelo</a>, <a href="/search/quant-ph?searchtype=author&query=De+Santis%2C+L">Lorenzo De Santis</a>, <a href="/search/quant-ph?searchtype=author&query=Shtyrkova%2C+K">Katia Shtyrkova</a>, <a href="/search/quant-ph?searchtype=author&query=Starling%2C+D">David Starling</a>, <a href="/search/quant-ph?searchtype=author&query=Murphy%2C+R">Ryan Murphy</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+L">Linsen Li</a>, <a href="/search/quant-ph?searchtype=author&query=Berggren%2C+K">Karl Berggren</a>, <a href="/search/quant-ph?searchtype=author&query=Dixon%2C+P+B">P. Benjamin Dixon</a>, <a href="/search/quant-ph?searchtype=author&query=Trusheim%2C+M">Matthew Trusheim</a>, <a href="/search/quant-ph?searchtype=author&query=Englund%2C+D">Dirk Englund</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="2402.18057v1-abstract-short" style="display: inline;"> A central challenge in quantum networking is transferring quantum states between different physical modalities, such as between flying photonic qubits and stationary quantum memories. One implementation entails using spin-photon interfaces that combine solid-state spin qubits, such as color centers in diamond, with photonic nanostructures. However, while high-fidelity spin-photon interactions have… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.18057v1-abstract-full').style.display = 'inline'; document.getElementById('2402.18057v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2402.18057v1-abstract-full" style="display: none;"> A central challenge in quantum networking is transferring quantum states between different physical modalities, such as between flying photonic qubits and stationary quantum memories. One implementation entails using spin-photon interfaces that combine solid-state spin qubits, such as color centers in diamond, with photonic nanostructures. However, while high-fidelity spin-photon interactions have been demonstrated on isolated devices, building practical quantum repeaters requires scaling to large numbers of interfaces yet to be realized. Here, we demonstrate integration of nanophotonic cavities containing tin-vacancy (SnV) centers in a photonic integrated circuit (PIC). Out of a six-channel quantum micro-chiplet (QMC), we find four coupled SnV-cavity devices with an average Purcell factor of ~7. Based on system analyses and numerical simulations, we find with near-term improvements this multiplexed architecture can enable high-fidelity quantum state transfer, paving the way towards building large-scale quantum repeaters. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.18057v1-abstract-full').style.display = 'none'; document.getElementById('2402.18057v1-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, 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">to be published in Optica Quantum</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2402.16070">arXiv:2402.16070</a> <span> [<a href="https://arxiv.org/pdf/2402.16070">pdf</a>, <a href="https://arxiv.org/format/2402.16070">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"> High-order topological pumping on a superconducting quantum processor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Deng%2C+C">Cheng-Lin Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+Y">Yu Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Y">Yu-Ran Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xue-Gang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+T">Tao Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Chi-Tong Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+T">Tong Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Lu%2C+C">Cong-Wei Lu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Y">Yong-Yi Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+T">Tian-Ming Li</a>, <a href="/search/quant-ph?searchtype=author&query=Fang%2C+C">Cai-Ping Fang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+S">Si-Yun Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+J">Jia-Cheng Song</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+Y">Yue-Shan Xu</a>, <a href="/search/quant-ph?searchtype=author&query=He%2C+Y">Yang He</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+Z">Zheng-He Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+K">Kai-Xuan Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Xiang%2C+Z">Zhong-Cheng Xiang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+J">Jie-Ci Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zheng%2C+D">Dong-Ning Zheng</a>, <a href="/search/quant-ph?searchtype=author&query=Xue%2C+G">Guang-Ming Xue</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+K">Kai Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Yu%2C+H+F">H. F. Yu</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="2402.16070v1-abstract-short" style="display: inline;"> High-order topological phases of matter refer to the systems of $n$-dimensional bulk with the topology of $m$-th order, exhibiting $(n-m)$-dimensional boundary modes and can be characterized by topological pumping. Here, we experimentally demonstrate two types of second-order topological pumps, forming four 0-dimensional corner localized states on a 4$\times$4 square lattice array of 16 supercondu… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.16070v1-abstract-full').style.display = 'inline'; document.getElementById('2402.16070v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2402.16070v1-abstract-full" style="display: none;"> High-order topological phases of matter refer to the systems of $n$-dimensional bulk with the topology of $m$-th order, exhibiting $(n-m)$-dimensional boundary modes and can be characterized by topological pumping. Here, we experimentally demonstrate two types of second-order topological pumps, forming four 0-dimensional corner localized states on a 4$\times$4 square lattice array of 16 superconducting qubits. The initial ground state of the system for half-filling, as a product of four identical entangled 4-qubit states, is prepared using an adiabatic scheme. During the pumping procedure, we adiabatically modulate the superlattice Bose-Hubbard Hamiltonian by precisely controlling both the hopping strengths and on-site potentials. At the half pumping period, the system evolves to a corner-localized state in a quadrupole configuration. The robustness of the second-order topological pump is also investigated by introducing different on-site disorder. Our work studies the topological properties of high-order topological phases from the dynamical transport picture using superconducting qubits, which would inspire further research on high-order topological phases. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.16070v1-abstract-full').style.display = 'none'; document.getElementById('2402.16070v1-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 February, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2402.11056">arXiv:2402.11056</a> <span> [<a href="https://arxiv.org/pdf/2402.11056">pdf</a>, <a href="https://arxiv.org/format/2402.11056">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="Quantum Gases">cond-mat.quant-gas</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Atomic Physics">physics.atom-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.132.263601">10.1103/PhysRevLett.132.263601 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Enhancing a Many-body Dipolar Rydberg Tweezer Array with Arbitrary Local Controls </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Bornet%2C+G">Guillaume Bornet</a>, <a href="/search/quant-ph?searchtype=author&query=Emperauger%2C+G">Gabriel Emperauger</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Cheng Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Machado%2C+F">Francisco Machado</a>, <a href="/search/quant-ph?searchtype=author&query=Chern%2C+S">Sabrina Chern</a>, <a href="/search/quant-ph?searchtype=author&query=Leclerc%2C+L">Lucas Leclerc</a>, <a href="/search/quant-ph?searchtype=author&query=G%C3%A9ly%2C+B">Bastien G茅ly</a>, <a href="/search/quant-ph?searchtype=author&query=Barredo%2C+D">Daniel Barredo</a>, <a href="/search/quant-ph?searchtype=author&query=Lahaye%2C+T">Thierry Lahaye</a>, <a href="/search/quant-ph?searchtype=author&query=Yao%2C+N+Y">Norman Y. Yao</a>, <a href="/search/quant-ph?searchtype=author&query=Browaeys%2C+A">Antoine Browaeys</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="2402.11056v1-abstract-short" style="display: inline;"> We implement and characterize a protocol that enables arbitrary local controls in a dipolar atom array, where the degree of freedom is encoded in a pair of Rydberg states. Our approach relies on a combination of local addressing beams and global microwave fields. Using this method, we directly prepare two different types of three-atom entangled states, including a W-state and a state exhibiting fi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.11056v1-abstract-full').style.display = 'inline'; document.getElementById('2402.11056v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2402.11056v1-abstract-full" style="display: none;"> We implement and characterize a protocol that enables arbitrary local controls in a dipolar atom array, where the degree of freedom is encoded in a pair of Rydberg states. Our approach relies on a combination of local addressing beams and global microwave fields. Using this method, we directly prepare two different types of three-atom entangled states, including a W-state and a state exhibiting finite chirality. We verify the nature of the underlying entanglement by performing quantum state tomography. Finally, leveraging our ability to measure multi-basis, multi-body observables, we explore the adiabatic preparation of low-energy states in a frustrated geometry consisting of a pair of triangular plaquettes. By using local addressing to tune the symmetry of the initial state, we demonstrate the ability to prepare correlated states distinguished only by correlations of their chirality (a fundamentally six-body observable). Our protocol is generic, allowing for rotations on arbitrary subgroups of atoms within the array at arbitrary times during the experiment; this extends the scope of capabilities for quantum simulations of the dipolar XY model. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.11056v1-abstract-full').style.display = 'none'; document.getElementById('2402.11056v1-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 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">12 pages, 4 figures (main text) + 6 figures (Supplemental Material)</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 132, 263601 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2402.09335">arXiv:2402.09335</a> <span> [<a href="https://arxiv.org/pdf/2402.09335">pdf</a>, <a href="https://arxiv.org/ps/2402.09335">ps</a>, <a href="https://arxiv.org/format/2402.09335">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="Data Structures and Algorithms">cs.DS</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Probability">math.PR</span> </div> </div> <p class="title is-5 mathjax"> Efficient Unitary T-designs from Random Sums </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Chi-Fang Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Docter%2C+J">Jordan Docter</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+M">Michelle Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Bouland%2C+A">Adam Bouland</a>, <a href="/search/quant-ph?searchtype=author&query=Hayden%2C+P">Patrick Hayden</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="2402.09335v1-abstract-short" style="display: inline;"> Unitary $T$-designs play an important role in quantum information, with diverse applications in quantum algorithms, benchmarking, tomography, and communication. Until now, the most efficient construction of unitary $T$-designs for $n$-qudit systems has been via random local quantum circuits, which have been shown to converge to approximate $T$-designs in the diamond norm using $O(T^{5+o(1)} n^2)$… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.09335v1-abstract-full').style.display = 'inline'; document.getElementById('2402.09335v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2402.09335v1-abstract-full" style="display: none;"> Unitary $T$-designs play an important role in quantum information, with diverse applications in quantum algorithms, benchmarking, tomography, and communication. Until now, the most efficient construction of unitary $T$-designs for $n$-qudit systems has been via random local quantum circuits, which have been shown to converge to approximate $T$-designs in the diamond norm using $O(T^{5+o(1)} n^2)$ quantum gates. In this work, we provide a new construction of $T$-designs via random matrix theory using $\tilde{O}(T^2 n^2)$ quantum gates. Our construction leverages two key ideas. First, in the spirit of central limit theorems, we approximate the Gaussian Unitary Ensemble (GUE) by an i.i.d. sum of random Hermitian matrices. Second, we show that the product of just two exponentiated GUE matrices is already approximately Haar random. Thus, multiplying two exponentiated sums over rather simple random matrices yields a unitary $T$-design, via Hamiltonian simulation. A central feature of our proof is a new connection between the polynomial method in quantum query complexity and the large-dimension ($N$) expansion in random matrix theory. In particular, we show that the polynomial method provides exponentially improved bounds on the high moments of certain random matrix ensembles, without requiring intricate Weingarten calculations. In doing so, we define and solve a new type of moment problem on the unit circle, asking whether a finite number of equally weighted points, corresponding to eigenvalues of unitary matrices, can reproduce a given set of moments. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.09335v1-abstract-full').style.display = 'none'; document.getElementById('2402.09335v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 February, 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">112 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/2401.16177">arXiv:2401.16177</a> <span> [<a href="https://arxiv.org/pdf/2401.16177">pdf</a>, <a href="https://arxiv.org/format/2401.16177">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"> Iterative assembly of $^{171}$Yb atom arrays with cavity-enhanced optical lattices </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Norcia%2C+M+A">M. A. Norcia</a>, <a href="/search/quant-ph?searchtype=author&query=Kim%2C+H">H. Kim</a>, <a href="/search/quant-ph?searchtype=author&query=Cairncross%2C+W+B">W. B. Cairncross</a>, <a href="/search/quant-ph?searchtype=author&query=Stone%2C+M">M. Stone</a>, <a href="/search/quant-ph?searchtype=author&query=Ryou%2C+A">A. Ryou</a>, <a href="/search/quant-ph?searchtype=author&query=Jaffe%2C+M">M. Jaffe</a>, <a href="/search/quant-ph?searchtype=author&query=Brown%2C+M+O">M. O. Brown</a>, <a href="/search/quant-ph?searchtype=author&query=Barnes%2C+K">K. Barnes</a>, <a href="/search/quant-ph?searchtype=author&query=Battaglino%2C+P">P. Battaglino</a>, <a href="/search/quant-ph?searchtype=author&query=Bohdanowicz%2C+T+C">T. C. Bohdanowicz</a>, <a href="/search/quant-ph?searchtype=author&query=Brown%2C+A">A. Brown</a>, <a href="/search/quant-ph?searchtype=author&query=Cassella%2C+K">K. Cassella</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C+-">C. -A. Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Coxe%2C+R">R. Coxe</a>, <a href="/search/quant-ph?searchtype=author&query=Crow%2C+D">D. Crow</a>, <a href="/search/quant-ph?searchtype=author&query=Epstein%2C+J">J. Epstein</a>, <a href="/search/quant-ph?searchtype=author&query=Griger%2C+C">C. Griger</a>, <a href="/search/quant-ph?searchtype=author&query=Halperin%2C+E">E. Halperin</a>, <a href="/search/quant-ph?searchtype=author&query=Hummel%2C+F">F. Hummel</a>, <a href="/search/quant-ph?searchtype=author&query=Jones%2C+A+M+W">A. M. W. Jones</a>, <a href="/search/quant-ph?searchtype=author&query=Kindem%2C+J+M">J. M. Kindem</a>, <a href="/search/quant-ph?searchtype=author&query=King%2C+J">J. King</a>, <a href="/search/quant-ph?searchtype=author&query=Kotru%2C+K">K. Kotru</a>, <a href="/search/quant-ph?searchtype=author&query=Lauigan%2C+J">J. Lauigan</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+M">M. Li</a> , et al. (25 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="2401.16177v3-abstract-short" style="display: inline;"> Assembling and maintaining large arrays of individually addressable atoms is a key requirement for continued scaling of neutral-atom-based quantum computers and simulators. In this work, we demonstrate a new paradigm for assembly of atomic arrays, based on a synergistic combination of optical tweezers and cavity-enhanced optical lattices, and the incremental filling of a target array from a repeti… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.16177v3-abstract-full').style.display = 'inline'; document.getElementById('2401.16177v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2401.16177v3-abstract-full" style="display: none;"> Assembling and maintaining large arrays of individually addressable atoms is a key requirement for continued scaling of neutral-atom-based quantum computers and simulators. In this work, we demonstrate a new paradigm for assembly of atomic arrays, based on a synergistic combination of optical tweezers and cavity-enhanced optical lattices, and the incremental filling of a target array from a repetitively filled reservoir. In this protocol, the tweezers provide microscopic rearrangement of atoms, while the cavity-enhanced lattices enable the creation of large numbers of optical traps with sufficient depth for rapid low-loss imaging of atoms. We apply this protocol to demonstrate near-deterministic filling (99% per-site occupancy) of 1225-site arrays of optical traps. Because the reservoir is repeatedly filled with fresh atoms, the array can be maintained in a filled state indefinitely. We anticipate that this protocol will be compatible with mid-circuit reloading of atoms into a quantum processor, which will be a key capability for running large-scale error-corrected quantum computations whose durations exceed the lifetime of a single atom in the system. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.16177v3-abstract-full').style.display = 'none'; document.getElementById('2401.16177v3-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 June, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 29 January, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 pages, 6 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2401.11339">arXiv:2401.11339</a> <span> [<a href="https://arxiv.org/pdf/2401.11339">pdf</a>, <a href="https://arxiv.org/ps/2401.11339">ps</a>, <a href="https://arxiv.org/format/2401.11339">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Inner Structure of Many-Body Localization Transition and Fulfillment of Harris Criterion </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chen%2C+J">Jie Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Chun Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+X">Xiaoqun 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="2401.11339v1-abstract-short" style="display: inline;"> We treat disordered Heisenberg model in 1D as the "standard model" of many-body localization (MBL). Two independent order parameters stemming purely from the half-chain von Neumann entanglement entropy $S_{\textrm{vN}}$ are introduced to probe its eigenstate transition. From symmetry-endowed entropy decomposition, they are probability distribution deviation $|d(p_n)|$ and von Neumann entropy… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.11339v1-abstract-full').style.display = 'inline'; document.getElementById('2401.11339v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2401.11339v1-abstract-full" style="display: none;"> We treat disordered Heisenberg model in 1D as the "standard model" of many-body localization (MBL). Two independent order parameters stemming purely from the half-chain von Neumann entanglement entropy $S_{\textrm{vN}}$ are introduced to probe its eigenstate transition. From symmetry-endowed entropy decomposition, they are probability distribution deviation $|d(p_n)|$ and von Neumann entropy $S_{\textrm{vN}}^{n}(D_n\!=\!\mbox{max})$ of the maximum-dimensional symmetry subdivision. Finite-size analyses reveal that $\{p_n\}$ drives the localization transition, preceded by a thermalization breakdown transition governed by $\{S_{\textrm{vN}}^{n}\}$. For noninteracting case, these transitions coincide, but in interacting situation they separate. Such separability creates an intermediate phase region and may help discriminate between the Anderson and MBL transitions. An obstacle whose solution eludes community to date is the violation of Harris criterion in nearly all numeric investigations of MBL so far. Upon elucidating the mutually independent components in $S_{\textrm{vN}}$, it is clear that previous studies of eigenspectra, $S_{\textrm{vN}}$, and the like lack resolution to pinpoint (thus completely overlook) the crucial internal structures of the transition. We show, for the first time, that after this necessary decoupling, the universal critical exponents for both transitions of $|d(p_n)|$ and $S_{\textrm{vN}}^{n}(D_n\!=\!\mbox{max})$ fulfill the Harris criterion: $谓\approx2.0\ (谓\approx1.5)$ for quench (quasirandom) disorder. Our work puts forth "symmetry combined with entanglement" as the missing organization principle for the generic eigenstate matter and transition. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.11339v1-abstract-full').style.display = 'none'; document.getElementById('2401.11339v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 20 January, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2401.08452">arXiv:2401.08452</a> <span> [<a href="https://arxiv.org/pdf/2401.08452">pdf</a>, <a href="https://arxiv.org/format/2401.08452">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"> Incorporating Zero-Probability Constraints to Device-Independent Randomness Expansion </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Chun-Yu Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+K">Kai-Siang Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chung%2C+K">Kai-Min Chung</a>, <a href="/search/quant-ph?searchtype=author&query=Hsieh%2C+M">Min-Hsiu Hsieh</a>, <a href="/search/quant-ph?searchtype=author&query=Liang%2C+Y">Yeong-Cherng Liang</a>, <a href="/search/quant-ph?searchtype=author&query=Tabia%2C+G+N+M">Gelo Noel M. Tabia</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2401.08452v1-abstract-short" style="display: inline;"> One of the distinguishing features of quantum theory is that its measurement outcomes are usually unpredictable or, equivalently, random. Moreover, this randomness is certifiable with minimal assumptions in the so-called device-independent (DI) paradigm, where a device's behavior does not need to be presupposed but can be verified through the statistics it produces. In this work, we explore variou… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.08452v1-abstract-full').style.display = 'inline'; document.getElementById('2401.08452v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2401.08452v1-abstract-full" style="display: none;"> One of the distinguishing features of quantum theory is that its measurement outcomes are usually unpredictable or, equivalently, random. Moreover, this randomness is certifiable with minimal assumptions in the so-called device-independent (DI) paradigm, where a device's behavior does not need to be presupposed but can be verified through the statistics it produces. In this work, we explore various forms of randomness that are certifiable in this setting, where two users can perform two binary-outcome measurements on their shared entangled state. In this case, even though the Clauser-Horne-Shimony-Holt (CHSH) Bell-inequality violation is a pre-requisite for the generation of DI certifiable randomness, the CHSH value alone does not generally give a tight bound on the certifiable randomness. Here, we determine the certifiable randomness when zero-probability constraints are incorporated into the task of DI randomness expansion for the standard local and global randomness and the so-called "blind" randomness. Asymptotically, we observe consistent improvements in the amount of DI certifiable randomness (of all kinds) as we increase the number zero constraints for a wide range of given CHSH Bell violations. However, if we further optimize over the allowed CHSH values, then benefits of these additional constraints over the standard CHSH-based protocol are only found in the case of global and blind randomness. In contrast, in the regimes of finite data, these zero constraints only give a slight improvement in the local randomness rate when compared with all existing protocols. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.08452v1-abstract-full').style.display = 'none'; document.getElementById('2401.08452v1-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 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+7 pages, 3 figures, 2 tables</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2401.07039">arXiv:2401.07039</a> <span> [<a href="https://arxiv.org/pdf/2401.07039">pdf</a>, <a href="https://arxiv.org/format/2401.07039">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="Machine Learning">cs.LG</span> </div> </div> <p class="title is-5 mathjax"> Quantum Generative Diffusion Model: A Fully Quantum-Mechanical Model for Generating Quantum State Ensemble </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Chuangtao Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+Q">Qinglin Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+M">MengChu Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=He%2C+Z">Zhimin He</a>, <a href="/search/quant-ph?searchtype=author&query=Sun%2C+Z">Zhili Sun</a>, <a href="/search/quant-ph?searchtype=author&query=Situ%2C+H">Haozhen Situ</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2401.07039v4-abstract-short" style="display: inline;"> Classical diffusion models have shown superior generative results. Exploring them in the quantum domain can advance the field of quantum generative learning. This work introduces Quantum Generative Diffusion Model (QGDM) as their simple and elegant quantum counterpart. Through a non-unitary forward process, any target quantum state can be transformed into a completely mixed state that has the high… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.07039v4-abstract-full').style.display = 'inline'; document.getElementById('2401.07039v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2401.07039v4-abstract-full" style="display: none;"> Classical diffusion models have shown superior generative results. Exploring them in the quantum domain can advance the field of quantum generative learning. This work introduces Quantum Generative Diffusion Model (QGDM) as their simple and elegant quantum counterpart. Through a non-unitary forward process, any target quantum state can be transformed into a completely mixed state that has the highest entropy and maximum uncertainty about the system. A trainable backward process is used to recover the former from the latter. The design requirements for its backward process includes non-unitarity and small parameter count. We introduce partial trace operations to enforce non-unitary and reduce the number of trainable parameters by using a parameter-sharing strategy and incorporating temporal information as an input in the backward process. We present QGDM's resource-efficient version to reduce auxiliary qubits while preserving generative capabilities. QGDM exhibits faster convergence than Quantum Generative Adversarial Network (QGAN) because its adopted convex-based optimization can result in better convergence. The results of comparing it with QGAN demonstrate its effectiveness in generating both pure and mixed quantum states. It can achieve 53.02% higher fidelity in mixed-state generation than QGAN. The results highlight its great potential to tackle challenging quantum generation tasks. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.07039v4-abstract-full').style.display = 'none'; document.getElementById('2401.07039v4-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 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 13 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">Comments are welcome</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2401.05246">arXiv:2401.05246</a> <span> [<a href="https://arxiv.org/pdf/2401.05246">pdf</a>, <a href="https://arxiv.org/format/2401.05246">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> </div> </div> <p class="title is-5 mathjax"> Loophole-free test of macroscopic realism via high-order correlations of measurement </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wang%2C+P">Ping Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Chong Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Liao%2C+H">Hao Liao</a>, <a href="/search/quant-ph?searchtype=author&query=Vorobyov%2C+V+V">Vadim V. Vorobyov</a>, <a href="/search/quant-ph?searchtype=author&query=Wrachtrup%2C+J">Joerg Wrachtrup</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+a+R">and Ren-Bao 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="2401.05246v2-abstract-short" style="display: inline;"> Test of {macroscopic realism} (MR) is key to understanding the foundation of quantum mechanics. Due to the existence of the {non-invasive measurability} loophole and other interpretation loopholes, however, such test remains an open question. Here we propose a general inequality based on high-order correlations of measurements for a loophole-free test of MR at the weak signal limit. Importantly, t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.05246v2-abstract-full').style.display = 'inline'; document.getElementById('2401.05246v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2401.05246v2-abstract-full" style="display: none;"> Test of {macroscopic realism} (MR) is key to understanding the foundation of quantum mechanics. Due to the existence of the {non-invasive measurability} loophole and other interpretation loopholes, however, such test remains an open question. Here we propose a general inequality based on high-order correlations of measurements for a loophole-free test of MR at the weak signal limit. Importantly, the inequality is established using the statistics of \textit{raw data} recorded by classical devices, without requiring a specific model for the measurement process, so its violation would falsify MR without the interpretation loophole. The non-invasive measurability loophole is also closed, since the weak signal limit can be verified solely by measurement data (using the relative scaling behaviors of different orders of correlations). We demonstrate that the inequality can be broken by a quantum spin model. The inequality proposed here provides an unambiguous test of the MR principle and is also useful to characterizing {quantum coherence}. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.05246v2-abstract-full').style.display = 'none'; document.getElementById('2401.05246v2-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, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 10 January, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2401.01530">arXiv:2401.01530</a> <span> [<a href="https://arxiv.org/pdf/2401.01530">pdf</a>, <a href="https://arxiv.org/format/2401.01530">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"> Disorder-induced topological pumping on a superconducting quantum processor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Liu%2C+Y">Yu Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Y">Yu-Ran Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Shi%2C+Y">Yun-Hao Shi</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+T">Tao Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Lu%2C+C">Congwei Lu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Y">Yong-Yi Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+H">Hao Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+T">Tian-Ming Li</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+C">Cheng-Lin Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+S">Si-Yun Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+T">Tong Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+J">Jia-Chi Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Liang%2C+G">Gui-Han Liang</a>, <a href="/search/quant-ph?searchtype=author&query=Mei%2C+Z">Zheng-Yang Mei</a>, <a href="/search/quant-ph?searchtype=author&query=Ma%2C+W">Wei-Guo Ma</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+H">Hao-Tian Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+Z">Zheng-He Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Chi-Tong Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+K">Kaixuan Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+X">Xiaohui Song</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+S">SP Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Tian%2C+Y">Ye Tian</a>, <a href="/search/quant-ph?searchtype=author&query=Xiang%2C+Z">Zhongcheng Xiang</a>, <a href="/search/quant-ph?searchtype=author&query=Zheng%2C+D">Dongning Zheng</a>, <a href="/search/quant-ph?searchtype=author&query=Nori%2C+F">Franco Nori</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="2401.01530v1-abstract-short" style="display: inline;"> Thouless pumping, a dynamical version of the integer quantum Hall effect, represents the quantized charge pumped during an adiabatic cyclic evolution. Here we report experimental observations of nontrivial topological pumping that is induced by disorder even during a topologically trivial pumping trajectory. With a 41-qubit superconducting quantum processor, we develop a Floquet engineering techni… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.01530v1-abstract-full').style.display = 'inline'; document.getElementById('2401.01530v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2401.01530v1-abstract-full" style="display: none;"> Thouless pumping, a dynamical version of the integer quantum Hall effect, represents the quantized charge pumped during an adiabatic cyclic evolution. Here we report experimental observations of nontrivial topological pumping that is induced by disorder even during a topologically trivial pumping trajectory. With a 41-qubit superconducting quantum processor, we develop a Floquet engineering technique to realize cycles of adiabatic pumping by simultaneously varying the on-site potentials and the hopping couplings. We demonstrate Thouless pumping in the presence of disorder and show its breakdown as the strength of disorder increases. Moreover, we observe two types of topological pumping that are induced by on-site potential disorder and hopping disorder, respectively. Especially, an intrinsic topological pump that is induced by quasi-periodic hopping disorder has never been experimentally realized before. Our highly controllable system provides a valuable quantum simulating platform for studying various aspects of topological physics in the presence of disorder. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.01530v1-abstract-full').style.display = 'none'; document.getElementById('2401.01530v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 2 January, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2312.01023">arXiv:2312.01023</a> <span> [<a href="https://arxiv.org/pdf/2312.01023">pdf</a>, <a href="https://arxiv.org/format/2312.01023">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"> Efficient Postprocessing Procedure for Evaluating Hamiltonian Expectation Values in Variational Quantum Eigensolver </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Chi-Chun Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Goan%2C+H">Hsi-Sheng Goan</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="2312.01023v2-abstract-short" style="display: inline;"> We proposed a simple strategy to improve the postprocessing overhead of evaluating Hamiltonian expectation values in Variational quantum eigensolvers (VQEs). Observing the fact that for a mutually commuting observable group G in a given Hamiltonian, <b|G|b> is fixed for a measurement outcome bit string $b$ in the corresponding basis, we create a measurement memory (MM) dictionary for every commuti… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.01023v2-abstract-full').style.display = 'inline'; document.getElementById('2312.01023v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2312.01023v2-abstract-full" style="display: none;"> We proposed a simple strategy to improve the postprocessing overhead of evaluating Hamiltonian expectation values in Variational quantum eigensolvers (VQEs). Observing the fact that for a mutually commuting observable group G in a given Hamiltonian, <b|G|b> is fixed for a measurement outcome bit string $b$ in the corresponding basis, we create a measurement memory (MM) dictionary for every commuting operator group G in a Hamiltonian. Once a measurement outcome bit string $b$ appears, we store $b$ and <b|G|b> as key and value, and the next time the same bit string appears, we can find <b|G|b> from the memory, rather than evaluate it once again. We further analyze the complexity of MM and compare it with commonly employed post-processing procedure, finding that MM is always more efficient in terms of time complexity. We implement this procedure on the task of minimizing a fully connected Ising Hamiltonians up to 20 qubits, and $H_2$, $H_4$, $LiH$, and $H_2O$ molecular Hamiltonians with different grouping methods. For Ising Hamiltonian, where all $O(N^2)$ terms commute, our method offers an $O(N^2)$ speedup in terms of the percentage of time saved. In the case of molecular Hamiltonians, we achieved over $O(N)$ percentage time saved, depending on the grouping method. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.01023v2-abstract-full').style.display = 'none'; document.getElementById('2312.01023v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 December, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 1 December, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2023. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2312.00892">arXiv:2312.00892</a> <span> [<a href="https://arxiv.org/pdf/2312.00892">pdf</a>, <a href="https://arxiv.org/format/2312.00892">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"> Black-Litterman Portfolio Optimization with Noisy Intermediate-Scale Quantum Computers </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Chi-Chun Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chung%2C+S">San-Lin Chung</a>, <a href="/search/quant-ph?searchtype=author&query=Goan%2C+H">Hsi-Sheng Goan</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="2312.00892v1-abstract-short" style="display: inline;"> In this work, we demonstrate a practical application of noisy intermediate-scale quantum (NISQ) algorithms to enhance subroutines in the Black-Litterman (BL) portfolio optimization model. As a proof of concept, we implement a 12-qubit example for selecting 6 assets out of a 12-asset pool. Our approach involves predicting investor views with quantum machine learning (QML) and addressing the subsequ… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.00892v1-abstract-full').style.display = 'inline'; document.getElementById('2312.00892v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2312.00892v1-abstract-full" style="display: none;"> In this work, we demonstrate a practical application of noisy intermediate-scale quantum (NISQ) algorithms to enhance subroutines in the Black-Litterman (BL) portfolio optimization model. As a proof of concept, we implement a 12-qubit example for selecting 6 assets out of a 12-asset pool. Our approach involves predicting investor views with quantum machine learning (QML) and addressing the subsequent optimization problem using the variational quantum eigensolver (VQE). The solutions obtained from VQE exhibit a high approximation ratio behavior, and consistently outperform several common portfolio models in backtesting over a long period of time. A unique aspect of our VQE scheme is that after the quantum circuit is optimized, only a minimal number of samplings is required to give a high approximation ratio result since the probability distribution should be concentrated on high-quality solutions. We further emphasize the importance of employing only a small number of final samplings in our scheme by comparing the cost with those obtained from an exhaustive search and random sampling. The power of quantum computing can be anticipated when dealing with a larger-size problem due to the linear growth of the required qubit resources with the problem size. This is in contrast to classical computing where the search space grows exponentially with the problem size and would quickly reach the limit of classical computers. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.00892v1-abstract-full').style.display = 'none'; document.getElementById('2312.00892v1-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 December, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2023. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2311.11726">arXiv:2311.11726</a> <span> [<a href="https://arxiv.org/pdf/2311.11726">pdf</a>, <a href="https://arxiv.org/format/2311.11726">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="Atomic Physics">physics.atom-ph</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"> Spectroscopy of elementary excitations from quench dynamics in a dipolar XY Rydberg simulator </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Cheng Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Emperauger%2C+G">Gabriel Emperauger</a>, <a href="/search/quant-ph?searchtype=author&query=Bornet%2C+G">Guillaume Bornet</a>, <a href="/search/quant-ph?searchtype=author&query=Caleca%2C+F">Filippo Caleca</a>, <a href="/search/quant-ph?searchtype=author&query=G%C3%A9ly%2C+B">Bastien G茅ly</a>, <a href="/search/quant-ph?searchtype=author&query=Bintz%2C+M">Marcus Bintz</a>, <a href="/search/quant-ph?searchtype=author&query=Chatterjee%2C+S">Shubhayu Chatterjee</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+V">Vincent Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Barredo%2C+D">Daniel Barredo</a>, <a href="/search/quant-ph?searchtype=author&query=Yao%2C+N+Y">Norman Y. Yao</a>, <a href="/search/quant-ph?searchtype=author&query=Lahaye%2C+T">Thierry Lahaye</a>, <a href="/search/quant-ph?searchtype=author&query=Mezzacapo%2C+F">Fabio Mezzacapo</a>, <a href="/search/quant-ph?searchtype=author&query=Roscilde%2C+T">Tommaso Roscilde</a>, <a href="/search/quant-ph?searchtype=author&query=Browaeys%2C+A">Antoine Browaeys</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="2311.11726v2-abstract-short" style="display: inline;"> We use a Rydberg quantum simulator to demonstrate a new form of spectroscopy, called quench spectroscopy, which probes the low-energy excitations of a many-body system. We illustrate the method on a two-dimensional simulation of the spin-1/2 dipolar XY model. Through microscopic measurements of the spatial spin correlation dynamics following a quench, we extract the dispersion relation of the elem… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.11726v2-abstract-full').style.display = 'inline'; document.getElementById('2311.11726v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2311.11726v2-abstract-full" style="display: none;"> We use a Rydberg quantum simulator to demonstrate a new form of spectroscopy, called quench spectroscopy, which probes the low-energy excitations of a many-body system. We illustrate the method on a two-dimensional simulation of the spin-1/2 dipolar XY model. Through microscopic measurements of the spatial spin correlation dynamics following a quench, we extract the dispersion relation of the elementary excitations for both ferro- and anti-ferromagnetic couplings. We observe qualitatively different behaviors between the two cases that result from the long-range nature of the interactions, and the frustration inherent in the antiferromagnet. In particular, the ferromagnet exhibits elementary excitations behaving as linear spin waves. In the anti-ferromagnet, spin waves appear to decay, suggesting the presence of strong nonlinearities. Our demonstration highlights the importance of power-law interactions on the excitation spectrum of a many-body system. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.11726v2-abstract-full').style.display = 'none'; document.getElementById('2311.11726v2-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 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 20 November, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 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">Main text 8 pages with 4 figures ; Supplemental Material 16 pages and 13 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/2311.09207">arXiv:2311.09207</a> <span> [<a href="https://arxiv.org/pdf/2311.09207">pdf</a>, <a href="https://arxiv.org/format/2311.09207">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="Mathematical Physics">math-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Functional Analysis">math.FA</span> </div> </div> <p class="title is-5 mathjax"> An efficient and exact noncommutative quantum Gibbs sampler </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Chi-Fang Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Kastoryano%2C+M+J">Michael J. Kastoryano</a>, <a href="/search/quant-ph?searchtype=author&query=Gily%C3%A9n%2C+A">Andr谩s Gily茅n</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="2311.09207v1-abstract-short" style="display: inline;"> Preparing thermal and ground states is an essential quantum algorithmic task for quantum simulation. In this work, we construct the first efficiently implementable and exactly detailed-balanced Lindbladian for Gibbs states of arbitrary noncommutative Hamiltonians. Our construction can also be regarded as a continuous-time quantum analog of the Metropolis-Hastings algorithm. To prepare the quantum… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.09207v1-abstract-full').style.display = 'inline'; document.getElementById('2311.09207v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2311.09207v1-abstract-full" style="display: none;"> Preparing thermal and ground states is an essential quantum algorithmic task for quantum simulation. In this work, we construct the first efficiently implementable and exactly detailed-balanced Lindbladian for Gibbs states of arbitrary noncommutative Hamiltonians. Our construction can also be regarded as a continuous-time quantum analog of the Metropolis-Hastings algorithm. To prepare the quantum Gibbs state, our algorithm invokes Hamiltonian simulation for a time proportional to the mixing time and the inverse temperature $尾$, up to polylogarithmic factors. Moreover, the gate complexity reduces significantly for lattice Hamiltonians as the corresponding Lindblad operators are (quasi-) local (with radius $\sim尾$) and only depend on local Hamiltonian patches. Meanwhile, purifying our Lindbladians yields a temperature-dependent family of frustration-free "parent Hamiltonians", prescribing an adiabatic path for the canonical purified Gibbs state (i.e., the Thermal Field Double state). These favorable features suggest that our construction is the ideal quantum algorithmic counterpart of classical Markov chain Monte Carlo sampling. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.09207v1-abstract-full').style.display = 'none'; document.getElementById('2311.09207v1-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 November, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 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">39 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/2311.08164">arXiv:2311.08164</a> <span> [<a href="https://arxiv.org/pdf/2311.08164">pdf</a>, <a href="https://arxiv.org/format/2311.08164">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"> Full characterization of biphotons with a generalized quantum interferometer </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+B">Baihong Li</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Changhua Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Yuan%2C+B">Boxin Yuan</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+X">Xiaofei Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Dong%2C+R">Ruifang Dong</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+S">Shougang Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Jin%2C+R">Rui-Bo Jin</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="2311.08164v3-abstract-short" style="display: inline;"> Entangled photons (biphotons) in the time-frequency degree of freedom play a crucial role in both foundational physics and advanced quantum technologies. Fully characterizing them poses a key scientific challenge. Here, we propose a theoretical approach to achieving the complete tomography of biphotons by introducing a frequency shift in one arm of the combination interferometer. Our method, a gen… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.08164v3-abstract-full').style.display = 'inline'; document.getElementById('2311.08164v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2311.08164v3-abstract-full" style="display: none;"> Entangled photons (biphotons) in the time-frequency degree of freedom play a crucial role in both foundational physics and advanced quantum technologies. Fully characterizing them poses a key scientific challenge. Here, we propose a theoretical approach to achieving the complete tomography of biphotons by introducing a frequency shift in one arm of the combination interferometer. Our method, a generalized combination interferometer, enables the reconstruction of the full complex joint spectral amplitude associated with both frequency sum and difference in a single interferometer. In contrast, the generalized Hong-Ou-Mandel and N00N state interferometers only allow for the partial tomography of biphotons, either in frequency difference or frequency sum. This provides an alternative method for full characterization of an arbitrary two-photon state with exchange symmetry and holds potential for applications in high-dimensional quantum information processing. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.08164v3-abstract-full').style.display = 'none'; document.getElementById('2311.08164v3-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 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 14 November, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 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">14 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/2310.14645">arXiv:2310.14645</a> <span> [<a href="https://arxiv.org/pdf/2310.14645">pdf</a>, <a href="https://arxiv.org/format/2310.14645">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.110.012211">10.1103/PhysRevA.110.012211 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Temperature-heat uncertainty relation in nonequilibrium quantum thermometry </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+N">Ning Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Bai%2C+S">Si-Yuan Bai</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Chong Chen</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="2310.14645v2-abstract-short" style="display: inline;"> We investigate the temperature uncertainty relation in nonequilibrium probe-based temperature estimation process. We demonstrate that it is the fluctuation of heat that fundamentally determines temperature precision through the temperature-heat uncertainty relation. Specifically, we find that heat is divided into trajectory heat and correlation heat, which are associated with the heat exchange alo… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.14645v2-abstract-full').style.display = 'inline'; document.getElementById('2310.14645v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2310.14645v2-abstract-full" style="display: none;"> We investigate the temperature uncertainty relation in nonequilibrium probe-based temperature estimation process. We demonstrate that it is the fluctuation of heat that fundamentally determines temperature precision through the temperature-heat uncertainty relation. Specifically, we find that heat is divided into trajectory heat and correlation heat, which are associated with the heat exchange along thermometer's evolution and the correlation between the thermometer and the sample, respectively. Based on two type of thermometers, we show that both of these heat terms are resources for enhancing temperature precision. By clearly distinguishing the resources for enhancing estimation precision, our findings not only explain why various quantum features are crucial for accurate temperature sensing but also provide valuable insights for designing ultrahigh-sensitive quantum thermometers. Additionally, we demonstrate that the temperature-heat uncertainty relation is consistent with the well-known temperature-energy uncertainty relation in thermodynamics. It establishes a connection between the information theory and the thermodynamics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.14645v2-abstract-full').style.display = 'none'; document.getElementById('2310.14645v2-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 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 23 October, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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">6 pages, 1 figure</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. A 110, 012211 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2310.10365">arXiv:2310.10365</a> <span> [<a href="https://arxiv.org/pdf/2310.10365">pdf</a>, <a href="https://arxiv.org/format/2310.10365">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> </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.131.133601">10.1103/PhysRevLett.131.133601 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Berry Curvature and Bulk-Boundary Correspondence from Transport Measurement for Photonic Chern Bands </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Chao Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+R">Run-Ze Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+J">Jizhou Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Su%2C+Z">Zu-En Su</a>, <a href="/search/quant-ph?searchtype=author&query=Ding%2C+X">Xing Ding</a>, <a href="/search/quant-ph?searchtype=author&query=Qin%2C+J">Jian Qin</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+L">Lin Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+W">Wei-Wei Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=He%2C+Y">Yu He</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+X">Xi-Lin Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Lu%2C+C">Chao-Yang Lu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+L">Li Li</a>, <a href="/search/quant-ph?searchtype=author&query=Sanders%2C+B+C">Barry C. Sanders</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+X">Xiong-Jun Liu</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="2310.10365v1-abstract-short" style="display: inline;"> Berry curvature is a fundamental element to characterize topological quantum physics, while a full measurement of Berry curvature in momentum space was not reported for topological states. Here we achieve two-dimensional Berry curvature reconstruction in a photonic quantum anomalous Hall system via Hall transport measurement of a momentum-resolved wave packet. Integrating measured Berry curvature… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.10365v1-abstract-full').style.display = 'inline'; document.getElementById('2310.10365v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2310.10365v1-abstract-full" style="display: none;"> Berry curvature is a fundamental element to characterize topological quantum physics, while a full measurement of Berry curvature in momentum space was not reported for topological states. Here we achieve two-dimensional Berry curvature reconstruction in a photonic quantum anomalous Hall system via Hall transport measurement of a momentum-resolved wave packet. Integrating measured Berry curvature over the two-dimensional Brillouin zone, we obtain Chern numbers corresponding to -1 and 0. Further, we identify bulk-boundary correspondence by measuring topology-linked chiral edge states at the boundary. The full topological characterization of photonic Chern bands from Berry curvature, Chern number, and edge transport measurements enables our photonic system to serve as a versatile platform for further in-depth study of novel topological physics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.10365v1-abstract-full').style.display = 'none'; document.getElementById('2310.10365v1-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 October, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 131, 133601 (25 September 2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2310.06565">arXiv:2310.06565</a> <span> [<a href="https://arxiv.org/pdf/2310.06565">pdf</a>, <a href="https://arxiv.org/format/2310.06565">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/s41467-024-52082-2">10.1038/s41467-024-52082-2 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Probing spin hydrodynamics on a superconducting quantum simulator </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Shi%2C+Y">Yun-Hao Shi</a>, <a href="/search/quant-ph?searchtype=author&query=Sun%2C+Z">Zheng-Hang Sun</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Y">Yong-Yi Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zheng-An Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Y">Yu-Ran Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Ma%2C+W">Wei-Guo Ma</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+H">Hao-Tian Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+K">Kui Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+J">Jia-Cheng Song</a>, <a href="/search/quant-ph?searchtype=author&query=Liang%2C+G">Gui-Han Liang</a>, <a href="/search/quant-ph?searchtype=author&query=Mei%2C+Z">Zheng-Yang Mei</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+J">Jia-Chi Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+H">Hao Li</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Chi-Tong Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+X">Xiaohui Song</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+J">Jieci Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Xue%2C+G">Guangming Xue</a>, <a href="/search/quant-ph?searchtype=author&query=Yu%2C+H">Haifeng Yu</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+K">Kaixuan Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Xiang%2C+Z">Zhongcheng Xiang</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+K">Kai Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Zheng%2C+D">Dongning Zheng</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="2310.06565v3-abstract-short" style="display: inline;"> Characterizing the nature of hydrodynamical transport properties in quantum dynamics provides valuable insights into the fundamental understanding of exotic non-equilibrium phases of matter. Experimentally simulating infinite-temperature transport on large-scale complex quantum systems is of considerable interest. Here, using a controllable and coherent superconducting quantum simulator, we experi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.06565v3-abstract-full').style.display = 'inline'; document.getElementById('2310.06565v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2310.06565v3-abstract-full" style="display: none;"> Characterizing the nature of hydrodynamical transport properties in quantum dynamics provides valuable insights into the fundamental understanding of exotic non-equilibrium phases of matter. Experimentally simulating infinite-temperature transport on large-scale complex quantum systems is of considerable interest. Here, using a controllable and coherent superconducting quantum simulator, we experimentally realize the analog quantum circuit, which can efficiently prepare the Haar-random states, and probe spin transport at infinite temperature. We observe diffusive spin transport during the unitary evolution of the ladder-type quantum simulator with ergodic dynamics. Moreover, we explore the transport properties of the systems subjected to strong disorder or a tilted potential, revealing signatures of anomalous subdiffusion in accompany with the breakdown of thermalization. Our work demonstrates a scalable method of probing infinite-temperature spin transport on analog quantum simulators, which paves the way to study other intriguing out-of-equilibrium phenomena from the perspective of transport. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.06565v3-abstract-full').style.display = 'none'; document.getElementById('2310.06565v3-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 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 10 October, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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">Main text: 13 pages, 5 figures; Supplementary: 17 pages, 16 figures, 1 table</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nat. Commun. 15, 7573 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2310.03011">arXiv:2310.03011</a> <span> [<a href="https://arxiv.org/pdf/2310.03011">pdf</a>, <a href="https://arxiv.org/format/2310.03011">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 algorithms: A survey of applications and end-to-end complexities </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Dalzell%2C+A+M">Alexander M. Dalzell</a>, <a href="/search/quant-ph?searchtype=author&query=McArdle%2C+S">Sam McArdle</a>, <a href="/search/quant-ph?searchtype=author&query=Berta%2C+M">Mario Berta</a>, <a href="/search/quant-ph?searchtype=author&query=Bienias%2C+P">Przemyslaw Bienias</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+C">Chi-Fang Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Gily%C3%A9n%2C+A">Andr谩s Gily茅n</a>, <a href="/search/quant-ph?searchtype=author&query=Hann%2C+C+T">Connor T. Hann</a>, <a href="/search/quant-ph?searchtype=author&query=Kastoryano%2C+M+J">Michael J. Kastoryano</a>, <a href="/search/quant-ph?searchtype=author&query=Khabiboulline%2C+E+T">Emil T. Khabiboulline</a>, <a href="/search/quant-ph?searchtype=author&query=Kubica%2C+A">Aleksander Kubica</a>, <a href="/search/quant-ph?searchtype=author&query=Salton%2C+G">Grant Salton</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+S">Samson Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Brand%C3%A3o%2C+F+G+S+L">Fernando G. S. L. Brand茫o</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="2310.03011v1-abstract-short" style="display: inline;"> The anticipated applications of quantum computers span across science and industry, ranging from quantum chemistry and many-body physics to optimization, finance, and machine learning. Proposed quantum solutions in these areas typically combine multiple quantum algorithmic primitives into an overall quantum algorithm, which must then incorporate the methods of quantum error correction and fault to… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.03011v1-abstract-full').style.display = 'inline'; document.getElementById('2310.03011v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2310.03011v1-abstract-full" style="display: none;"> The anticipated applications of quantum computers span across science and industry, ranging from quantum chemistry and many-body physics to optimization, finance, and machine learning. Proposed quantum solutions in these areas typically combine multiple quantum algorithmic primitives into an overall quantum algorithm, which must then incorporate the methods of quantum error correction and fault tolerance to be implemented correctly on quantum hardware. As such, it can be difficult to assess how much a particular application benefits from quantum computing, as the various approaches are often sensitive to intricate technical details about the underlying primitives and their complexities. Here we present a survey of several potential application areas of quantum algorithms and their underlying algorithmic primitives, carefully considering technical caveats and subtleties. We outline the challenges and opportunities in each area in an "end-to-end" fashion by clearly defining the problem being solved alongside the input-output model, instantiating all "oracles," and spelling out all hidden costs. We also compare quantum solutions against state-of-the-art classical methods and complexity-theoretic limitations to evaluate possible quantum speedups. The survey is written in a modular, wiki-like fashion to facilitate navigation of the content. Each primitive and application area is discussed in a standalone section, with its own bibliography of references and embedded hyperlinks that direct to other relevant sections. This structure mirrors that of complex quantum algorithms that involve several layers of abstraction, and it enables rapid evaluation of how end-to-end complexities are impacted when subroutines are altered. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.03011v1-abstract-full').style.display = 'none'; document.getElementById('2310.03011v1-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 October, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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">Survey document with wiki-like modular structure. 337 pages, including bibliography and sub-bibliographies. Comments welcome</span> </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=Chen%2C+C&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Chen%2C+C&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=Chen%2C+C&start=50" class="pagination-link " aria-label="Page 2" aria-current="page">2 </a> </li> <li> <a href="/search/?searchtype=author&query=Chen%2C+C&start=100" class="pagination-link " aria-label="Page 3" aria-current="page">3 </a> </li> <li> <a href="/search/?searchtype=author&query=Chen%2C+C&start=150" class="pagination-link " aria-label="Page 4" aria-current="page">4 </a> </li> <li> <a href="/search/?searchtype=author&query=Chen%2C+C&start=200" 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