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class="breathe-horizontal" start="1"> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2502.13018">arXiv:2502.13018</a> <span> [<a href="https://arxiv.org/pdf/2502.13018">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Applied Physics">physics.app-ph</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/10.1021/acsnano.4c16450">10.1021/acsnano.4c16450 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Artificially creating emergent interfacial antiferromagnetism and its manipulation in a magnetic van-der-Waals heterostructure </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wang%2C+X">Xiangqi Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+C">Cong Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Y">Yupeng Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Ye%2C+C">Chunhui Ye</a>, <a href="/search/quant-ph?searchtype=author&query=Rahman%2C+A">Azizur Rahman</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+M">Min Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Son%2C+S">Suhan Son</a>, <a href="/search/quant-ph?searchtype=author&query=Tan%2C+J">Jun Tan</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Z">Zengming Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Ji%2C+W">Wei Ji</a>, <a href="/search/quant-ph?searchtype=author&query=Park%2C+J">Je-Geun Park</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kai-Xuan Zhang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2502.13018v1-abstract-short" style="display: inline;"> Van der Waals (vdW) magnets, with their two-dimensional (2D) atomic structures, provide a unique platform for exploring magnetism at the nanoscale. Although there have been numerous reports on their diverse quantum properties, the emergent interfacial magnetism--artificially created at the interface between two layered magnets--remains largely unexplored. This work presents observations of such em… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.13018v1-abstract-full').style.display = 'inline'; document.getElementById('2502.13018v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2502.13018v1-abstract-full" style="display: none;"> Van der Waals (vdW) magnets, with their two-dimensional (2D) atomic structures, provide a unique platform for exploring magnetism at the nanoscale. Although there have been numerous reports on their diverse quantum properties, the emergent interfacial magnetism--artificially created at the interface between two layered magnets--remains largely unexplored. This work presents observations of such emergent interfacial magnetism at the ferromagnet/antiferromagnet interface in a vdW heterostructure. We report the discovery of an intermediate Hall resistance plateau in the anomalous Hall loop, indicative of emergent interfacial antiferromagnetism fostered by the heterointerface. This plateau can be stabilized and further manipulated under varying pressures but collapses under high pressures over 10 GPa. Our theoretical calculations reveal that charge transfer at the interface is pivotal in establishing the interlayer antiferromagnetic spin-exchange interaction. This work illuminates the previously unexplored emergent interfacial magnetism at a vdW interface comprised of a ferromagnetic metal and an antiferromagnetic insulator, and highlights its gradual evolution under increasing pressure. These findings enrich the portfolio of emergent interfacial magnetism and support further investigations on vdW magnetic interfaces and the development of next-generation spintronic devices. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.13018v1-abstract-full').style.display = 'none'; document.getElementById('2502.13018v1-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 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2025. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted by ACS Nano; 42 pages, 5 main figures, 8 supporting 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/2502.07513">arXiv:2502.07513</a> <span> [<a href="https://arxiv.org/pdf/2502.07513">pdf</a>, <a href="https://arxiv.org/format/2502.07513">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/1674-1056/ad9a9d">10.1088/1674-1056/ad9a9d <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Entanglement and energy transportation in the central-spin quantum battery </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Liu%2C+F">Fan Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+H">Hui-Yu Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+S">Shuai-Li Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+J">Jun-Zhong Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kun Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+X">Xiao-Hui 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="2502.07513v1-abstract-short" style="display: inline;"> Quantum battery exploits the principle of quantum mechanics to transport and store energy. We study the energy transportation of the central-spin quantum battery, which is composed of $N_b$ spins serving as the battery cells, and surrounded by $N_c$ spins serving as the charger cells. We apply the invariant subspace method to solve the dynamics of the central-spin battery with a large number of sp… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.07513v1-abstract-full').style.display = 'inline'; document.getElementById('2502.07513v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2502.07513v1-abstract-full" style="display: none;"> Quantum battery exploits the principle of quantum mechanics to transport and store energy. We study the energy transportation of the central-spin quantum battery, which is composed of $N_b$ spins serving as the battery cells, and surrounded by $N_c$ spins serving as the charger cells. We apply the invariant subspace method to solve the dynamics of the central-spin battery with a large number of spins. We establish a universal inverse relationship between the battery capacity and the battery-charger entanglement, which persists in any size of the battery and charger cells. Moreover, we find that when $N_b=N_c$, the central-spin battery has the optimal energy transportation, corresponding to the minimal battery-charger entanglement. Surprisingly, the central-spin battery has a uniform energy transportation behaviors in certain battery-charger scales. Our results reveal a nonmonotonic relationship between the battery-charger size and the energy transportation efficiency, which may provide more insights on designing other types of quantum batteries. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.07513v1-abstract-full').style.display = 'none'; document.getElementById('2502.07513v1-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 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2025. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Published version, 8 pages, 5 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Chin. Phys. B 34, 020306 (2025) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2502.01146">arXiv:2502.01146</a> <span> [<a href="https://arxiv.org/pdf/2502.01146">pdf</a>, <a href="https://arxiv.org/format/2502.01146">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Artificial Intelligence">cs.AI</span> <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 Machine Learning: A Hands-on Tutorial for Machine Learning Practitioners and Researchers </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Du%2C+Y">Yuxuan Du</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+X">Xinbiao Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+N">Naixu Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Yu%2C+Z">Zhan Yu</a>, <a href="/search/quant-ph?searchtype=author&query=Qian%2C+Y">Yang Qian</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kaining Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Hsieh%2C+M">Min-Hsiu Hsieh</a>, <a href="/search/quant-ph?searchtype=author&query=Rebentrost%2C+P">Patrick Rebentrost</a>, <a href="/search/quant-ph?searchtype=author&query=Tao%2C+D">Dacheng Tao</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2502.01146v1-abstract-short" style="display: inline;"> This tutorial intends to introduce readers with a background in AI to quantum machine learning (QML) -- a rapidly evolving field that seeks to leverage the power of quantum computers to reshape the landscape of machine learning. For self-consistency, this tutorial covers foundational principles, representative QML algorithms, their potential applications, and critical aspects such as trainability,… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.01146v1-abstract-full').style.display = 'inline'; document.getElementById('2502.01146v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2502.01146v1-abstract-full" style="display: none;"> This tutorial intends to introduce readers with a background in AI to quantum machine learning (QML) -- a rapidly evolving field that seeks to leverage the power of quantum computers to reshape the landscape of machine learning. For self-consistency, this tutorial covers foundational principles, representative QML algorithms, their potential applications, and critical aspects such as trainability, generalization, and computational complexity. In addition, practical code demonstrations are provided in https://qml-tutorial.github.io/ to illustrate real-world implementations and facilitate hands-on learning. Together, these elements offer readers a comprehensive overview of the latest advancements in QML. By bridging the gap between classical machine learning and quantum computing, this tutorial serves as a valuable resource for those looking to engage with QML and explore the forefront of AI in the quantum era. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.01146v1-abstract-full').style.display = 'none'; document.getElementById('2502.01146v1-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 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2025. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">260 pages; 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/2501.02070">arXiv:2501.02070</a> <span> [<a href="https://arxiv.org/pdf/2501.02070">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Applied Physics">physics.app-ph</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/10.1038/s41535-025-00725-y">10.1038/s41535-025-00725-y <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Magnetoelectric effect in van der Waals magnets </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kai-Xuan Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Park%2C+G">Giung Park</a>, <a href="/search/quant-ph?searchtype=author&query=Lee%2C+Y">Youjin Lee</a>, <a href="/search/quant-ph?searchtype=author&query=Kim%2C+B+H">Beom Hyun Kim</a>, <a href="/search/quant-ph?searchtype=author&query=Park%2C+J">Je-Geun Park</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="2501.02070v2-abstract-short" style="display: inline;"> The magnetoelectric (ME) effect is a fundamental concept in modern condensed matter physics and represents the electrical control of magnetic polarisations or vice versa. Two-dimensional (2D) van-der-Waals (vdW) magnets have emerged as a new class of materials and exhibit novel ME effects with diverse manifestations. This review emphasizes some important recent discoveries unique to vdW magnets: m… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.02070v2-abstract-full').style.display = 'inline'; document.getElementById('2501.02070v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.02070v2-abstract-full" style="display: none;"> The magnetoelectric (ME) effect is a fundamental concept in modern condensed matter physics and represents the electrical control of magnetic polarisations or vice versa. Two-dimensional (2D) van-der-Waals (vdW) magnets have emerged as a new class of materials and exhibit novel ME effects with diverse manifestations. This review emphasizes some important recent discoveries unique to vdW magnets: multiferroicity on two dimensions, spin-charge correlation, atomic ME effect and current-induced intrinsic spin-orbit torque, and electrical gating control and magnetic control of their electronic properties. We also highlight the promising route of utilizing quantum magnetic hetero- or homo-structures to engineer the ME effect and corresponding spintronic and optoelectronic device applications. Due to the intrinsic two-dimensionality, vdW magnets with those ME effects are expected to form a new, exciting research direction. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.02070v2-abstract-full').style.display = 'none'; document.getElementById('2501.02070v2-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 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 3 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted by npj Quantum Materials; 27 pages, 6 main figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> npj Quantum Materials 10, 6 (2025) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2412.12339">arXiv:2412.12339</a> <span> [<a href="https://arxiv.org/pdf/2412.12339">pdf</a>, <a href="https://arxiv.org/format/2412.12339">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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="Other Condensed Matter">cond-mat.other</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Nuclear Experiment">nucl-ex</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"> Laser-Induced Quenching of the Th-229 Nuclear Clock Isomer in Calcium Fluoride </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Schaden%2C+F">F. Schaden</a>, <a href="/search/quant-ph?searchtype=author&query=Riebner%2C+T">T. Riebner</a>, <a href="/search/quant-ph?searchtype=author&query=Morawetz%2C+I">I. Morawetz</a>, <a href="/search/quant-ph?searchtype=author&query=De+Col%2C+L+T">L. Toscani De Col</a>, <a href="/search/quant-ph?searchtype=author&query=Kazakov%2C+G+A">G. A. Kazakov</a>, <a href="/search/quant-ph?searchtype=author&query=Beeks%2C+K">K. Beeks</a>, <a href="/search/quant-ph?searchtype=author&query=Sikorsky%2C+T">T. Sikorsky</a>, <a href="/search/quant-ph?searchtype=author&query=Schumm%2C+T">T. Schumm</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">K. Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Lal%2C+V">V. Lal</a>, <a href="/search/quant-ph?searchtype=author&query=Zitzer%2C+G">G. Zitzer</a>, <a href="/search/quant-ph?searchtype=author&query=Tiedau%2C+J">J. Tiedau</a>, <a href="/search/quant-ph?searchtype=author&query=Okhapkin%2C+M+V">M. V. Okhapkin</a>, <a href="/search/quant-ph?searchtype=author&query=Peik%2C+E">E. Peik</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2412.12339v1-abstract-short" style="display: inline;"> The 10-minute radiative lifetime of the first excited $^{229}$Th$^{4+}$ nuclear state in ionic crystals provides narrow spectroscopic linewidths, enabling the realization of a solid-state nuclear clock. Due to the 4+ noble gas configuration, electronic readout or state initialization schemes known from atomic clocks are inaccessible. This elongates the interrogation cycle, which will deteriorate t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.12339v1-abstract-full').style.display = 'inline'; document.getElementById('2412.12339v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.12339v1-abstract-full" style="display: none;"> The 10-minute radiative lifetime of the first excited $^{229}$Th$^{4+}$ nuclear state in ionic crystals provides narrow spectroscopic linewidths, enabling the realization of a solid-state nuclear clock. Due to the 4+ noble gas configuration, electronic readout or state initialization schemes known from atomic clocks are inaccessible. This elongates the interrogation cycle, which will deteriorate the clock performance. To address this limitation we demonstrate laser-induced quenching (LIQ) as a method of depumping the $^{229}$Th isomer population in CaF$_2$. We provide experimental evidence for LIQ at different wavelengths (148 - 420 nm) and temperatures (100 - 350 K), achieving a threefold reduction in the isomer lifetime with 20 mW of laser power. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.12339v1-abstract-full').style.display = 'none'; document.getElementById('2412.12339v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2024. </p> <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, 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/2412.11924">arXiv:2412.11924</a> <span> [<a href="https://arxiv.org/pdf/2412.11924">pdf</a>, <a href="https://arxiv.org/format/2412.11924">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Establishing a New Benchmark in Quantum Computational Advantage with 105-qubit Zuchongzhi 3.0 Processor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Gao%2C+D">Dongxin Gao</a>, <a href="/search/quant-ph?searchtype=author&query=Fan%2C+D">Daojin Fan</a>, <a href="/search/quant-ph?searchtype=author&query=Zha%2C+C">Chen Zha</a>, <a href="/search/quant-ph?searchtype=author&query=Bei%2C+J">Jiahao Bei</a>, <a href="/search/quant-ph?searchtype=author&query=Cai%2C+G">Guoqing Cai</a>, <a href="/search/quant-ph?searchtype=author&query=Cai%2C+J">Jianbin Cai</a>, <a href="/search/quant-ph?searchtype=author&query=Cao%2C+S">Sirui Cao</a>, <a href="/search/quant-ph?searchtype=author&query=Zeng%2C+X">Xiangdong Zeng</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+F">Fusheng Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+J">Jiang Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+K">Kefu Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+X">Xiawei Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+X">Xiqing Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Z">Zhe Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Z">Zhiyuan Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Z">Zihua Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chu%2C+W">Wenhao Chu</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+H">Hui Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+Z">Zhibin Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Ding%2C+P">Pei Ding</a>, <a href="/search/quant-ph?searchtype=author&query=Ding%2C+X">Xun Ding</a>, <a href="/search/quant-ph?searchtype=author&query=Ding%2C+Z">Zhuzhengqi Ding</a>, <a href="/search/quant-ph?searchtype=author&query=Dong%2C+S">Shuai Dong</a>, <a href="/search/quant-ph?searchtype=author&query=Dong%2C+Y">Yupeng Dong</a>, <a href="/search/quant-ph?searchtype=author&query=Fan%2C+B">Bo Fan</a> , et al. (129 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2412.11924v1-abstract-short" style="display: inline;"> In the relentless pursuit of quantum computational advantage, we present a significant advancement with the development of Zuchongzhi 3.0. This superconducting quantum computer prototype, comprising 105 qubits, achieves high operational fidelities, with single-qubit gates, two-qubit gates, and readout fidelity at 99.90%, 99.62% and 99.18%, respectively. Our experiments with an 83-qubit, 32-cycle r… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.11924v1-abstract-full').style.display = 'inline'; document.getElementById('2412.11924v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.11924v1-abstract-full" style="display: none;"> In the relentless pursuit of quantum computational advantage, we present a significant advancement with the development of Zuchongzhi 3.0. This superconducting quantum computer prototype, comprising 105 qubits, achieves high operational fidelities, with single-qubit gates, two-qubit gates, and readout fidelity at 99.90%, 99.62% and 99.18%, respectively. Our experiments with an 83-qubit, 32-cycle random circuit sampling on Zuchongzhi 3.0 highlight its superior performance, achieving one million samples in just a few hundred seconds. This task is estimated to be infeasible on the most powerful classical supercomputers, Frontier, which would require approximately $6.4\times 10^9$ years to replicate the task. This leap in processing power places the classical simulation cost six orders of magnitude beyond Google's SYC-67 and SYC-70 experiments [Nature 634, 328(2024)], firmly establishing a new benchmark in quantum computational advantage. Our work not only advances the frontiers of quantum computing but also lays the groundwork for a new era where quantum processors play an essential role in tackling sophisticated real-world challenges. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.11924v1-abstract-full').style.display = 'none'; document.getElementById('2412.11924v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.12297">arXiv:2411.12297</a> <span> [<a href="https://arxiv.org/pdf/2411.12297">pdf</a>, <a href="https://arxiv.org/format/2411.12297">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 Indistinguishable Obfuscation via Quantum Circuit Equivalence </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Y">Yuanjing Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Shang%2C+T">Tao Shang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kun Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+C">Chenyi Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Du%2C+H">Haohua Du</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+X">Xueyi Guo</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="2411.12297v1-abstract-short" style="display: inline;"> Quantum computing solutions are increasingly deployed in commercial environments through delegated computing, especially one of the most critical issues is to guarantee the confidentiality and proprietary of quantum implementations. Since the proposal of general-purpose indistinguishability obfuscation (iO) and functional encryption schemes, iO has emerged as a seemingly versatile cryptography pri… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.12297v1-abstract-full').style.display = 'inline'; document.getElementById('2411.12297v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.12297v1-abstract-full" style="display: none;"> Quantum computing solutions are increasingly deployed in commercial environments through delegated computing, especially one of the most critical issues is to guarantee the confidentiality and proprietary of quantum implementations. Since the proposal of general-purpose indistinguishability obfuscation (iO) and functional encryption schemes, iO has emerged as a seemingly versatile cryptography primitive. Existing research on quantum indistinguishable obfuscation (QiO) primarily focuses on task-oriented, lacking solutions to general quantum computing. In this paper, we propose a scheme for constructing QiO via the equivalence of quantum circuits. It introduces the concept of quantum subpath sum equivalence, demonstrating that indistinguishability between two quantum circuits can be achieved by incremental changes in quantum subpaths. The restriction of security loss is solved by reducing the distinguisher to polynomial probability test. The scheme obfuscates the quantum implementation of classical functions in a path-sum specification, ensuring the indistinguishability between different quantum implementations. The results demonstrate the feasibility of indistinguishability obfuscation for general circuits and provide novel insights on intellectual property protection and secure delegated quantum computing. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.12297v1-abstract-full').style.display = 'none'; document.getElementById('2411.12297v1-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">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/2411.04558">arXiv:2411.04558</a> <span> [<a href="https://arxiv.org/pdf/2411.04558">pdf</a>, <a href="https://arxiv.org/format/2411.04558">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> </div> </div> <p class="title is-5 mathjax"> Experimental Secure Multiparty Computation from Quantum Oblivious Transfer with Bit Commitment </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kai-Yi Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+A">An-Jing Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Tu%2C+K">Kun Tu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+M">Ming-Han Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+C">Chi Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Qi%2C+W">Wei Qi</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Ya-Dong Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Yu%2C+Y">Yu 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="2411.04558v1-abstract-short" style="display: inline;"> Secure multiparty computation enables collaborative computations across multiple users while preserving individual privacy, which has a wide range of applications in finance, machine learning and healthcare. Secure multiparty computation can be realized using oblivious transfer as a primitive function. In this paper, we present an experimental implementation of a quantum-secure quantum oblivious t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.04558v1-abstract-full').style.display = 'inline'; document.getElementById('2411.04558v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.04558v1-abstract-full" style="display: none;"> Secure multiparty computation enables collaborative computations across multiple users while preserving individual privacy, which has a wide range of applications in finance, machine learning and healthcare. Secure multiparty computation can be realized using oblivious transfer as a primitive function. In this paper, we present an experimental implementation of a quantum-secure quantum oblivious transfer (QOT) protocol using an adapted quantum key distribution system combined with a bit commitment scheme, surpassing previous approaches only secure in the noisy storage model. We demonstrate the first practical application of the QOT protocol by solving the private set intersection, a prime example of secure multiparty computation, where two parties aim to find common elements in their datasets without revealing any other information. In our experiments, two banks can identify common suspicious accounts without disclosing any other data. This not only proves the experimental functionality of QOT, but also showcases its real-world commercial applications. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.04558v1-abstract-full').style.display = 'none'; document.getElementById('2411.04558v1-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 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/2411.03897">arXiv:2411.03897</a> <span> [<a href="https://arxiv.org/pdf/2411.03897">pdf</a>, <a href="https://arxiv.org/format/2411.03897">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"> Autonomous Quantum Heat Engine Enabled by Molecular Optomechanics and Hysteresis Switching </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+B">Baiqiang Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Meystre%2C+P">Pierre Meystre</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+W">Weiping Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Keye 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="2411.03897v1-abstract-short" style="display: inline;"> By integrating molecular optomechanics with molecular switches, we propose a scheme for a molecular quantum heat engine that operates autonomously through hysteretic feedback without external driving or modulation. Through a comparative analysis conducted within both semiclassical and fully quantum frameworks, we reveal the influence of quantum properties embedded within the autonomous control ele… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.03897v1-abstract-full').style.display = 'inline'; document.getElementById('2411.03897v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.03897v1-abstract-full" style="display: none;"> By integrating molecular optomechanics with molecular switches, we propose a scheme for a molecular quantum heat engine that operates autonomously through hysteretic feedback without external driving or modulation. Through a comparative analysis conducted within both semiclassical and fully quantum frameworks, we reveal the influence of quantum properties embedded within the autonomous control elements on the operational efficiency and performance of this advanced molecular machine. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.03897v1-abstract-full').style.display = 'none'; document.getElementById('2411.03897v1-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 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">12 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/2411.01175">arXiv:2411.01175</a> <span> [<a href="https://arxiv.org/pdf/2411.01175">pdf</a>, <a href="https://arxiv.org/format/2411.01175">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/PhysRevB.111.085410">10.1103/PhysRevB.111.085410 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Optimal energy storage and collective charging speedup in the central-spin quantum battery </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Yang%2C+H">Hui-Yu Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kun Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+X">Xiao-Hui Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Shi%2C+H">Hai-Long Shi</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="2411.01175v2-abstract-short" style="display: inline;"> Quantum batteries (QBs) exploit principles of quantum mechanics to accelerate the charging process and aim to achieve optimal energy storage. However, analytical results for investigating these problems remain lacking due to the challenges associated with nonequilibrium dynamics. In this work, we analytically investigate a central-spin QB model in which $N_b$ spin-1/2 battery cells interact with… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.01175v2-abstract-full').style.display = 'inline'; document.getElementById('2411.01175v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.01175v2-abstract-full" style="display: none;"> Quantum batteries (QBs) exploit principles of quantum mechanics to accelerate the charging process and aim to achieve optimal energy storage. However, analytical results for investigating these problems remain lacking due to the challenges associated with nonequilibrium dynamics. In this work, we analytically investigate a central-spin QB model in which $N_b$ spin-1/2 battery cells interact with $N_c$ spin-1/2 charger units, using $m$ initially excited charger units as a resource. By employing the invariant subspace method and the shifted Holstein-Primakoff transformation, we identify four scenarios in which optimal energy storage can be achieved: (i) $N_b\!\ll\!m\!\ll\!N_c$; (ii) $m\!\ll\!N_b\!\ll\!N_c$; (iii) $m\!\ll\!N_c\!\ll\!N_b$; and (iv) $N_b\!\ll\!m\!=\!kN_c$ [$k\!\in\!(0,1)$]. In these cases, optimal storage is ensured by the SU(2) symmetry emerging from the charging dynamics. The first three cases map the central-spin QB to different Tavis-Cummings (TC) QBs, while the fourth corresponds to the non-TC limit. We analytically determine the charging time and demonstrate that in the fully charging cases (i) and (iv), the collective charging exhibits an $N_b$-fold enhancement in speedup compared to the parallel charging scheme. Additionally, we numerically observe a unified charging behavior when $m\!=\!N_c$, showing that asymptotically optimal energy storage is possible when $N_b\!=\!m\!=\!N_c$. In this case, we find a collective charging enhancement scaling as $N_b^{0.8264}$. The origin of the collective charging advantage in central-spin quantum batteries is also analyzed through the quantum speed limit and a multipartite entanglement witness. Our results highlight the crucial role of dynamically emergent SU(2) symmetry in providing an analytical understanding of non-equilibrium charging dynamics in QBs. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.01175v2-abstract-full').style.display = 'none'; document.getElementById('2411.01175v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 2 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">10 pages, 6 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 111, 085410 (2025) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.23674">arXiv:2410.23674</a> <span> [<a href="https://arxiv.org/pdf/2410.23674">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> </div> </div> <p class="title is-5 mathjax"> Atom-light-correlated quantum interferometer with memory-induced phase comb </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Huang%2C+W">Wenfeng Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Liang%2C+X">Xinyun Liang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+J">Jie Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Z">Zeliang Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Keye Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Yuan%2C+C">Chun-Hua Yuan</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yuan Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Fan%2C+B">Bixuan Fan</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+W">Weiping Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+L">Liqing 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="2410.23674v1-abstract-short" style="display: inline;"> Precise phase measurements by interferometers are crucial in science for detecting subtle changes, such as gravitational waves. However, phase sensitivity is typically limited by the standard quantum limit (SQL) with uncorrelated particles N. This limit can be surpassed using quantum correlations, but achieving high-quality correlations in large systems is challenging. Here, we propose and demonst… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.23674v1-abstract-full').style.display = 'inline'; document.getElementById('2410.23674v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.23674v1-abstract-full" style="display: none;"> Precise phase measurements by interferometers are crucial in science for detecting subtle changes, such as gravitational waves. However, phase sensitivity is typically limited by the standard quantum limit (SQL) with uncorrelated particles N. This limit can be surpassed using quantum correlations, but achieving high-quality correlations in large systems is challenging. Here, we propose and demonstrate an atom-light hybrid quantum interferometry whose sensitivity is enhanced beyond the SQL with atom-light quantum correlation and newly developed phase comb superposition via atomic-memory-assisted multiple quantum amplification. Finally, a phase sensitivity beyond the SQL of up to $8.3\pm 0.2$ dB is achieved, especially at $N=4 \times10^{13}/s$, resulting in both atomic and optical phase sensitivities of $6\times10^{-8} rad/\sqrt{Hz}$. This technique can advance sensitive quantum measurements in various fields. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.23674v1-abstract-full').style.display = 'none'; document.getElementById('2410.23674v1-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">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, 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/2410.15455">arXiv:2410.15455</a> <span> [<a href="https://arxiv.org/pdf/2410.15455">pdf</a>, <a href="https://arxiv.org/format/2410.15455">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> <p class="title is-5 mathjax"> Observation of quantum information collapse-and-revival in a strongly-interacting Rydberg atom array </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Xiang%2C+D">De-Sheng Xiang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Y">Yao-Wen Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+H">Hao-Xiang Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+P">Peng Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Yuan%2C+D">Dong Yuan</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kuan Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+S">Shun-Yao Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+B">Biao Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+L">Lu Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yitong Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+L">Lin Li</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2410.15455v1-abstract-short" style="display: inline;"> Interactions of isolated quantum many-body systems typically scramble local information into the entire system and make it unrecoverable. Ergodicity-breaking systems possess the potential to exhibit fundamentally different information scrambling dynamics beyond this paradigm. For many-body localized systems with strong ergodicity breaking, local transport vanishes and information scrambles logarit… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.15455v1-abstract-full').style.display = 'inline'; document.getElementById('2410.15455v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.15455v1-abstract-full" style="display: none;"> Interactions of isolated quantum many-body systems typically scramble local information into the entire system and make it unrecoverable. Ergodicity-breaking systems possess the potential to exhibit fundamentally different information scrambling dynamics beyond this paradigm. For many-body localized systems with strong ergodicity breaking, local transport vanishes and information scrambles logarithmically slowly. Whereas in Rydberg atom arrays, local qubit flips induce dynamical retardation on surrounding qubits through the Rydberg blockade effect, giving rise to quantum many-body scars that weakly break ergodicity, and resulting in the predicted unconventional quantum information spreading behaviours. Here, we present the first measurements of out-of-time-ordered correlators and Holevo information in a Rydberg atom array, enabling us to precisely track quantum information scrambling and transport dynamics. By leveraging these tools, we observe a novel spatio-temporal collapse-and-revival behaviour of quantum information, which differs from both typical chaotic and many-body localized systems. Our experiment sheds light on the unique information dynamics in many-body systems with kinetic constraints, and demonstrates an effective digital-analogue approach to coherently reverse time evolution and steer information propagation in near-term quantum devices. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.15455v1-abstract-full').style.display = 'none'; document.getElementById('2410.15455v1-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 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">12 pages, 6 figures + Supplementary Information 37 pages, 24 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2409.13623">arXiv:2409.13623</a> <span> [<a href="https://arxiv.org/pdf/2409.13623">pdf</a>, <a href="https://arxiv.org/format/2409.13623">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 Gases">cond-mat.quant-gas</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Ultra spectral sensitivity and non-local bi-impurity bound states from quasi-long-range non-hermitian skin modes </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Shu%2C+C">Chang Shu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kai Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Sun%2C+K">Kai Sun</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="2409.13623v1-abstract-short" style="display: inline;"> A fundamental tenet of quantum mechanics is that the energy spectrum of a quantum system shall remain stable against infinitesimally weak and spatially confined perturbations. In this article, we demonstrate that this principle of spectral stability fails in non-Hermitian systems at the thermodynamic limit. Consider, for instance, a non-interacting non-Hermitian system $H_0$ with a couple of point… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.13623v1-abstract-full').style.display = 'inline'; document.getElementById('2409.13623v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.13623v1-abstract-full" style="display: none;"> A fundamental tenet of quantum mechanics is that the energy spectrum of a quantum system shall remain stable against infinitesimally weak and spatially confined perturbations. In this article, we demonstrate that this principle of spectral stability fails in non-Hermitian systems at the thermodynamic limit. Consider, for instance, a non-interacting non-Hermitian system $H_0$ with a couple of point-like impurities, each of which introduces a local short-range potential $V_i$ with $i=1, \ldots, n$ labeling the impurities. If the impurity potentials are sufficiently weak, introducing a single impurity will not alter the spectrum; that is, $H_0$ and $H_0 + V_1$ have nearly identical energy spectra. However, if a second impurity is introduced, $H_0 + V_1 + V_2$, we find that no matter how weak these local potentials are, as long as the distance between them is sufficiently large, significant alterations in the energy spectrum can arise, directly contradicting the traditional expectation of a stable spectrum. Remarkably, this phenomenon is non-local, and the impact of the perturbations increases exponentially with the distance between the two impurities. In other words, although the Hamiltonian is entirely local, its energy spectrum, which is blind to the presence of a single infinitesimally weak impurity, is capable of detecting the presence of two infinitesimally weak impurities separated by a large distance in space. Using Green's function techniques, we uncover the origin of this spectral sensitivity, which arises from the formation of non-local bi-impurity bound states: non-local stationary states with wavepackets propagating back-and-forth between the two impurities. We provide an analytic theory to identify and characterize such spectral instabilities, showing perfect agreement with numerical solutions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.13623v1-abstract-full').style.display = 'none'; document.getElementById('2409.13623v1-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 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">16 pages, 11 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2409.13025">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/2409.03473">arXiv:2409.03473</a> <span> [<a href="https://arxiv.org/pdf/2409.03473">pdf</a>, <a href="https://arxiv.org/ps/2409.03473">ps</a>, <a href="https://arxiv.org/format/2409.03473">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"> Purification of Gaussian States by Photon Subtraction </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kun Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+H">Huijun Li</a>, <a href="/search/quant-ph?searchtype=author&query=Jing%2C+J">Jietai Jing</a>, <a href="/search/quant-ph?searchtype=author&query=Treps%2C+N">Nicolas Treps</a>, <a href="/search/quant-ph?searchtype=author&query=Walschaers%2C+M">Mattia Walschaers</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="2409.03473v1-abstract-short" style="display: inline;"> Photon subtraction can enhance entanglement, which for pure states induces a decrease in the purity of reduced states. In contrast, by analyzing the purities of Gaussian states before and after subtracting a single photon, we prove that the purity of a Gaussian state can also be increased by less than 20%. On the one hand, it reveals that photon subtraction can reduce entanglement, and on the othe… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.03473v1-abstract-full').style.display = 'inline'; document.getElementById('2409.03473v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.03473v1-abstract-full" style="display: none;"> Photon subtraction can enhance entanglement, which for pure states induces a decrease in the purity of reduced states. In contrast, by analyzing the purities of Gaussian states before and after subtracting a single photon, we prove that the purity of a Gaussian state can also be increased by less than 20%. On the one hand, it reveals that photon subtraction can reduce entanglement, and on the other hand, it reveals that it can achieve a limited amount of Gaussian state purification. Through the analysis of some examples, we demonstrate the inherent mechanism and applicable scope of photon-subtraction-based purification. In a multimode system, we find that photon subtraction can increase entanglement and purify some of the reduced states simultaneously. We thus present purification through the suppression of Gaussian noise as a new application for photon subtraction in continuous-variable quantum information processing. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.03473v1-abstract-full').style.display = 'none'; document.getElementById('2409.03473v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 September, 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">7 pages, 3 figures, comments 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/2409.02710">arXiv:2409.02710</a> <span> [<a href="https://arxiv.org/pdf/2409.02710">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Applied Physics">physics.app-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"> Electrical control of topological 3Q state in an intercalated van der Waals antiferromagnet </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Kim%2C+J">Junghyun Kim</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kaixuan Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Park%2C+P">Pyeongjae Park</a>, <a href="/search/quant-ph?searchtype=author&query=Cho%2C+W">Woonghee Cho</a>, <a href="/search/quant-ph?searchtype=author&query=Kim%2C+H">Hyuncheol Kim</a>, <a href="/search/quant-ph?searchtype=author&query=Park%2C+J">Je-Geun Park</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="2409.02710v1-abstract-short" style="display: inline;"> Van der Waals (vdW) magnets have opened a new avenue of novel opportunities covering various interesting phases. Co1/3TaS2-an intercalated metallic vdW antiferromagnet-is one of the latest important additions to the growing list of materials due to its unique triple-Q (3Q) ground state possessing topological characteristics. Careful bulk characterisations have shown the ground state of CoxTaS2 to… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.02710v1-abstract-full').style.display = 'inline'; document.getElementById('2409.02710v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.02710v1-abstract-full" style="display: none;"> Van der Waals (vdW) magnets have opened a new avenue of novel opportunities covering various interesting phases. Co1/3TaS2-an intercalated metallic vdW antiferromagnet-is one of the latest important additions to the growing list of materials due to its unique triple-Q (3Q) ground state possessing topological characteristics. Careful bulk characterisations have shown the ground state of CoxTaS2 to be a rare 3Q tetrahedral structure for x less than 1/3. The uniqueness of this ground state arises from the dense real-space Berry curvature due to scalar spin chirality, giving rise to a noticeable anomalous Hall effect. In this work, we demonstrate that we can control this topological phase via gating. Using three kinds of CoxTaS2 devices with different Co compositions, we have established that we can cover the whole 3Q topological phase with ionic gating. This work reports a rare demonstration of electrical gating control of layered antiferromagnetic metal. More importantly, our work constitutes one of the first examples of the electrical control of the scalar spin chirality using antiferromagnetic metal. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.02710v1-abstract-full').style.display = 'none'; document.getElementById('2409.02710v1-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 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">19 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/2408.16997">arXiv:2408.16997</a> <span> [<a href="https://arxiv.org/pdf/2408.16997">pdf</a>, <a href="https://arxiv.org/format/2408.16997">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Statistical Mechanics">cond-mat.stat-mech</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.133.090402">10.1103/PhysRevLett.133.090402 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Experimental Verification of Demon-Involved Fluctuation Theorems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Yan%2C+L+-">L. -L. Yan</a>, <a href="/search/quant-ph?searchtype=author&query=Bu%2C+J+-">J. -T. Bu</a>, <a href="/search/quant-ph?searchtype=author&query=Zeng%2C+Q">Q. Zeng</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">K. Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Cui%2C+K+-">K. -F. Cui</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+F">F. Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Su%2C+S+-">S. -L. Su</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+L">L. Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+J">J. Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+G">Gang Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Feng%2C+M">M. Feng</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="2408.16997v1-abstract-short" style="display: inline;"> The limit of energy saving in the control of small systems has recently attracted much interest due to the concept refinement of the Maxwell demon. Inspired by a newly proposed set of fluctuation theorems, we report the first experimental verification of these equalities and inequalities in a ultracold 40Ca ion system, confirming the intrinsic nonequilibrium in the system due to involvement of the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.16997v1-abstract-full').style.display = 'inline'; document.getElementById('2408.16997v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.16997v1-abstract-full" style="display: none;"> The limit of energy saving in the control of small systems has recently attracted much interest due to the concept refinement of the Maxwell demon. Inspired by a newly proposed set of fluctuation theorems, we report the first experimental verification of these equalities and inequalities in a ultracold 40Ca ion system, confirming the intrinsic nonequilibrium in the system due to involvement of the demon. Based on elaborately designed demon-involved control protocols, such as the Szilard engine protocol, we provide experimentally quantitative evidence of the dissipative information, and observe tighter bounds of both the extracted work and the demon's efficacy than the limits predicted by the Sagawa-Ueda theorem. Our results substantiate a close connection between the physical nature of information and nonequilibrium processes at the microscale, which help further understanding the thermodynamic characteristics of information and the optimal design of nanoscale and smaller systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.16997v1-abstract-full').style.display = 'none'; document.getElementById('2408.16997v1-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 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">Journal ref:</span> Physical Review Letters 133, 090402 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.09937">arXiv:2408.09937</a> <span> [<a href="https://arxiv.org/pdf/2408.09937">pdf</a>, <a href="https://arxiv.org/format/2408.09937">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"> The curse of random quantum data </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kaining Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+J">Junyu Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+L">Liu Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Jiang%2C+L">Liang Jiang</a>, <a href="/search/quant-ph?searchtype=author&query=Hsieh%2C+M">Min-Hsiu Hsieh</a>, <a href="/search/quant-ph?searchtype=author&query=Tao%2C+D">Dacheng Tao</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="2408.09937v1-abstract-short" style="display: inline;"> Quantum machine learning, which involves running machine learning algorithms on quantum devices, may be one of the most significant flagship applications for these devices. Unlike its classical counterparts, the role of data in quantum machine learning has not been fully understood. In this work, we quantify the performances of quantum machine learning in the landscape of quantum data. Provided th… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.09937v1-abstract-full').style.display = 'inline'; document.getElementById('2408.09937v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.09937v1-abstract-full" style="display: none;"> Quantum machine learning, which involves running machine learning algorithms on quantum devices, may be one of the most significant flagship applications for these devices. Unlike its classical counterparts, the role of data in quantum machine learning has not been fully understood. In this work, we quantify the performances of quantum machine learning in the landscape of quantum data. Provided that the encoding of quantum data is sufficiently random, the performance, we find that the training efficiency and generalization capabilities in quantum machine learning will be exponentially suppressed with the increase in the number of qubits, which we call "the curse of random quantum data". Our findings apply to both the quantum kernel method and the large-width limit of quantum neural networks. Conversely, we highlight that through meticulous design of quantum datasets, it is possible to avoid these curses, thereby achieving efficient convergence and robust generalization. Our conclusions are corroborated by extensive numerical simulations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.09937v1-abstract-full').style.display = 'none'; document.getElementById('2408.09937v1-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 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">40 pages, 8 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.08194">arXiv:2408.08194</a> <span> [<a href="https://arxiv.org/pdf/2408.08194">pdf</a>, <a href="https://arxiv.org/format/2408.08194">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="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.110.184304">10.1103/PhysRevB.110.184304 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Two-doublon Bloch oscillations in the mass-imbalanced extended Fermi-Hubbard model </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kun-Liang Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Jiang%2C+X">Xun-Da Jiang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yong-Yao Li</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2408.08194v3-abstract-short" style="display: inline;"> Interactions between particles normally induce the decay of the particles Bloch oscillations (BOs) in a periodic lattice. In the limit of strong on-site interactions, spin-$1/2$ fermions may form doublon bound states and undergo BOs in the presence of a tilted potential. Here we investigate the impact of nearest-neighbor interaction $V$ on the multi-doublon BOs in a mass-imbalanced extended Fermi-… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.08194v3-abstract-full').style.display = 'inline'; document.getElementById('2408.08194v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.08194v3-abstract-full" style="display: none;"> Interactions between particles normally induce the decay of the particles Bloch oscillations (BOs) in a periodic lattice. In the limit of strong on-site interactions, spin-$1/2$ fermions may form doublon bound states and undergo BOs in the presence of a tilted potential. Here we investigate the impact of nearest-neighbor interaction $V$ on the multi-doublon BOs in a mass-imbalanced extended Fermi-Hubbard model. We derive an effective Hamiltonian for doublons, and show that a slight change in $V$ can qualitatively alter their dynamic behaviors. Notably, at a resonance point, the doublons behave like free hard-core bosons. Under a tilted potential, the system may exhibit different types of multi-doublon BOs at or deviation from the resonance point. Numerical results are presented to demonstrate our conclusions in both one- and two-dimensional systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.08194v3-abstract-full').style.display = 'none'; document.getElementById('2408.08194v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 13 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 15 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">12 pages, 7 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 110, 184304 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.10748">arXiv:2407.10748</a> <span> [<a href="https://arxiv.org/pdf/2407.10748">pdf</a>, <a href="https://arxiv.org/format/2407.10748">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1002/qute.202400557">10.1002/qute.202400557 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Near-deterministic quantum search algorithm without phase design </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zhen Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kun Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Korepin%2C+V">Vladimir Korepin</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="2407.10748v4-abstract-short" style="display: inline;"> Grover's algorithm solves the unstructured search problem. Grover's algorithm can find the target state with certainty only if searching one out of four. Designing the deterministic search algorithm can avoid any repetition of the algorithm, especially when Grover's algorithm is a subroutine in other algorithms. Grover's algorithm can be deterministic if the phase of the oracle or the diffusion op… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.10748v4-abstract-full').style.display = 'inline'; document.getElementById('2407.10748v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.10748v4-abstract-full" style="display: none;"> Grover's algorithm solves the unstructured search problem. Grover's algorithm can find the target state with certainty only if searching one out of four. Designing the deterministic search algorithm can avoid any repetition of the algorithm, especially when Grover's algorithm is a subroutine in other algorithms. Grover's algorithm can be deterministic if the phase of the oracle or the diffusion operator is delicately designed. The precision of the phases could be a problem. A near-deterministic quantum search algorithm without the phase design is proposed. The algorithm has the same oracle and diffusion operators as Grover's algorithm. One additional component is the rescaled diffusion operator. It acts partially on the database. The success probability of Grover's algorithm is improved by the partial diffusion operator in two different ways. The possible cost is one or two more queries to the oracle. The deterministic search algorithm is also designed when searching one out of eight, sixteen, and thirty-two. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.10748v4-abstract-full').style.display = 'none'; document.getElementById('2407.10748v4-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 13 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 15 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">Published version, 9 pages, 3 figures, 2 tables</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Adv. Quantum Technol. 2025, 2400557 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2406.08320">arXiv:2406.08320</a> <span> [<a href="https://arxiv.org/pdf/2406.08320">pdf</a>, <a href="https://arxiv.org/format/2406.08320">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="Mathematical Physics">math-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/1751-8121/ad85b2">10.1088/1751-8121/ad85b2 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Geometric representations of braid and Yang-Baxter gates </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kun Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Hao%2C+K">Kun Hao</a>, <a href="/search/quant-ph?searchtype=author&query=Yu%2C+K">Kwangmin Yu</a>, <a href="/search/quant-ph?searchtype=author&query=Korepin%2C+V">Vladimir Korepin</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+W">Wen-Li Yang</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="2406.08320v2-abstract-short" style="display: inline;"> Brick-wall circuits composed of the Yang-Baxter gates are integrable. It becomes an important tool to study the quantum many-body system out of equilibrium. To put the Yang-Baxter gate on quantum computers, it has to be decomposed into the native gates of quantum computers. It is favorable to apply the least number of native two-qubit gates to construct the Yang-Baxter gate. We study the geometric… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.08320v2-abstract-full').style.display = 'inline'; document.getElementById('2406.08320v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2406.08320v2-abstract-full" style="display: none;"> Brick-wall circuits composed of the Yang-Baxter gates are integrable. It becomes an important tool to study the quantum many-body system out of equilibrium. To put the Yang-Baxter gate on quantum computers, it has to be decomposed into the native gates of quantum computers. It is favorable to apply the least number of native two-qubit gates to construct the Yang-Baxter gate. We study the geometric representations of all X-type braid gates and their corresponding Yang-Baxter gates via the Yang-Baxterization. We find that the braid and Yang-Baxter gates can only exist on certain edges and faces of the two-qubit tetrahedron. We identify the parameters by which the braid and Yang-Baxter gates are the Clifford gate, the matchgate, and the dual-unitary gate. The geometric representations provide the optimal decompositions of the braid and Yang-Baxter gates in terms of other two-qubit gates. We also find that the entangling powers of the Yang-Baxter gates are determined by the spectral parameters. Our results provide the necessary conditions to construct the braid and Yang-Baxter gates on quantum computers. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.08320v2-abstract-full').style.display = 'none'; document.getElementById('2406.08320v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 12 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">Published version, 27 pages, 7 figures, 2 tables</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> J. Phys. A: Math. Theor. 57 445303 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2406.07626">arXiv:2406.07626</a> <span> [<a href="https://arxiv.org/pdf/2406.07626">pdf</a>, <a href="https://arxiv.org/format/2406.07626">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="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="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Tailoring Bound State Geometry in High-Dimensional Non-Hermitian Systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Yang%2C+A">Ao Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Fang%2C+Z">Zixi Fang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kai Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Fang%2C+C">Chen Fang</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="2406.07626v1-abstract-short" style="display: inline;"> It is generally believed that the non-Hermitian effect (NHSE), due to its non-reciprocal nature, creates barriers for the appearance of impurity bound states. In this paper, we find that in two and higher dimensions, the presence of geometry-dependent skin effect eliminates this barrier such that even an infinitesimal impurity potential can confine bound states in this type of non-Hermitian system… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.07626v1-abstract-full').style.display = 'inline'; document.getElementById('2406.07626v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2406.07626v1-abstract-full" style="display: none;"> It is generally believed that the non-Hermitian effect (NHSE), due to its non-reciprocal nature, creates barriers for the appearance of impurity bound states. In this paper, we find that in two and higher dimensions, the presence of geometry-dependent skin effect eliminates this barrier such that even an infinitesimal impurity potential can confine bound states in this type of non-Hermitian systems. By examining bound states around Bloch saddle points, we find that non-Hermiticity can disrupt the isotropy of bound states, resulting in concave dumbbell-shaped bound states. Our work reveals a geometry transition of bound state between concavity and convexity in high-dimensional non-Hermitian systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.07626v1-abstract-full').style.display = 'none'; document.getElementById('2406.07626v1-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 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">14 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/2406.06682">arXiv:2406.06682</a> <span> [<a href="https://arxiv.org/pdf/2406.06682">pdf</a>, <a href="https://arxiv.org/format/2406.06682">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 Gases">cond-mat.quant-gas</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Algebraic non-Hermitian skin effect and unified non-Bloch band theory in arbitrary dimensions </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kai Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Shu%2C+C">Chang Shu</a>, <a href="/search/quant-ph?searchtype=author&query=Sun%2C+K">Kai Sun</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="2406.06682v1-abstract-short" style="display: inline;"> The non-Hermitian skin effect, characterized by a proliferation of exponentially-localized edge modes, has led to numerous novel physical phenomena that challenge the limits of conventional band theory. In sharp contrast to the traditional exponential localization, this manuscript reports a new kind of non-Hermitian skin effect, which we term the ``algebraic non-Hermitian skin effect." This effect… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.06682v1-abstract-full').style.display = 'inline'; document.getElementById('2406.06682v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2406.06682v1-abstract-full" style="display: none;"> The non-Hermitian skin effect, characterized by a proliferation of exponentially-localized edge modes, has led to numerous novel physical phenomena that challenge the limits of conventional band theory. In sharp contrast to the traditional exponential localization, this manuscript reports a new kind of non-Hermitian skin effect, which we term the ``algebraic non-Hermitian skin effect." This effect emerges across a diverse spectrum of non-Hermitian systems in both two- and higher space dimensions. For 2D systems with algebraic non-Hermitian skin effect, on geometries such as a torus or cylinder, these systems exhibit behavior reminiscent of the conventional non-Hermitian skin effect, where eigenmodes are either bulk Bloch waves (on a torus) or exponentially localized edge modes (on a cylinder). However, if the same system is placed on a disk or any geometrical shape featuring open boundaries in all directions, the skin modes immediately transform into the algebraic form, with amplitude decaying as a power-law function of the distance from the boundary. To explore these novel effects, we formulate a unified generalized Brillouin zone (GBZ) framework that is universally applicable to all variations of non-Hermitian skin effects across any spatial dimension, developed through the usage of a generalized transfer-matrix approach. We find that in a $d$-dimensional non-Hermitian system, in general, the GBZ manifold's dimensionality must fall into the range from $d$ to $2d-1$, denoted by ${d \leq \dim\text{GBZ} \leq 2d-1}$. In 1D, this inequality is trivial because the upper and lower bounds converge, forcing the GBZ's dimensionality to match with that of the physical space. However, in 2D and above, this inequality indicates that there is no obligation for the GBZ's dimensionality to concur with the physical space's dimensionality, which gives rise to a new class of non-Hermitian skin effects. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.06682v1-abstract-full').style.display = 'none'; document.getElementById('2406.06682v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 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">19 pages, 5 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2404.18120">arXiv:2404.18120</a> <span> [<a href="https://arxiv.org/pdf/2404.18120">pdf</a>, <a href="https://arxiv.org/format/2404.18120">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1364/JOSAB.531886">10.1364/JOSAB.531886 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Performance advantage of quantum hypothesis testing for partially coherent optical sources </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+J">Jian-Dong Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kexin Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Hou%2C+L">Lili Hou</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+S">Shuai 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="2404.18120v1-abstract-short" style="display: inline;"> Determining the presence of a potential optical source in the interest region is important for an imaging system and can be achieved by using hypothesis testing. The previous studies assume that the potential source is completely incoherent. In this paper, this problem is generalized to the scenario with partially coherent sources and any prior probabilities. We compare the error probability limit… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.18120v1-abstract-full').style.display = 'inline'; document.getElementById('2404.18120v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2404.18120v1-abstract-full" style="display: none;"> Determining the presence of a potential optical source in the interest region is important for an imaging system and can be achieved by using hypothesis testing. The previous studies assume that the potential source is completely incoherent. In this paper, this problem is generalized to the scenario with partially coherent sources and any prior probabilities. We compare the error probability limit given by the quantum Helstrom bound with the error probability given by direct decision based on the prior probability. On this basis, the quantum-optimal detection advantage and detection-useless region are analyzed. For practical purposes, we propose a specific detection strategy using binary spatial-mode demultiplexing, which can be used in the scenarios without any prior information. This strategy shows superior detection performance and the results hold prospects for achieving super-resolved microscopic and astronomical imaging. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.18120v1-abstract-full').style.display = 'none'; document.getElementById('2404.18120v1-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 April, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2404.10173">arXiv:2404.10173</a> <span> [<a href="https://arxiv.org/pdf/2404.10173">pdf</a>, <a href="https://arxiv.org/format/2404.10173">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1364/OE.511600">10.1364/OE.511600 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Coherent control of an optical tweezer phonon laser </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kai Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Xiao%2C+K">Kewen Xiao</a>, <a href="/search/quant-ph?searchtype=author&query=Luntz-Martin%2C+D">Danika Luntz-Martin</a>, <a href="/search/quant-ph?searchtype=author&query=Sun%2C+P">Ping Sun</a>, <a href="/search/quant-ph?searchtype=author&query=Sharma%2C+S">S. Sharma</a>, <a href="/search/quant-ph?searchtype=author&query=Bhattacharya%2C+M">M. Bhattacharya</a>, <a href="/search/quant-ph?searchtype=author&query=Vamivakas%2C+A+N">A. N. Vamivakas</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="2404.10173v2-abstract-short" style="display: inline;"> The creation and manipulation of coherence continues to capture the attention of scientists and engineers. The optical laser is a canonical example of a system that, in principle, exhibits complete coherence. Recent research has focused on the creation of coherent, laser-like states in other physical systems. The phonon laser is one example where it is possible to amplify self-sustained mechanical… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.10173v2-abstract-full').style.display = 'inline'; document.getElementById('2404.10173v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2404.10173v2-abstract-full" style="display: none;"> The creation and manipulation of coherence continues to capture the attention of scientists and engineers. The optical laser is a canonical example of a system that, in principle, exhibits complete coherence. Recent research has focused on the creation of coherent, laser-like states in other physical systems. The phonon laser is one example where it is possible to amplify self-sustained mechanical oscillations. A single mode phonon laser in a levitated optical tweezer has been demonstrated through appropriate balance of active feedback gain and damping. In this work, coherent control of the dynamics of an optical tweezer phonon laser is used to share coherence between its different modes of oscillation, creating a multimode phonon laser. The coupling of the modes is achieved by periodically rotating the asymmetric optical potential in the transverse focal plane of the trapping beam via trap laser polarization rotation. The presented theory and experiment demonstrate that coherence can be transferred across different modes of an optical tweezer phonon laser, and are a step toward using these systems for precision measurement and quantum information processing. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.10173v2-abstract-full').style.display = 'none'; document.getElementById('2404.10173v2-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 April, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 15 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">\c{opyright} 2024 Optica Publishing Group. Users may use, reuse, and build upon the article, or use the article for text or data mining, so long as such uses are for non-commercial purposes and appropriate attribution is maintained. All other rights are reserved."</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Opt. Express 32, 14735-14745 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2404.08436">arXiv:2404.08436</a> <span> [<a href="https://arxiv.org/pdf/2404.08436">pdf</a>, <a href="https://arxiv.org/ps/2404.08436">ps</a>, <a href="https://arxiv.org/format/2404.08436">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.133.090801">10.1103/PhysRevLett.133.090801 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Enhanced Quantum Metrology with Non-Phase-Covariant Noise </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Peng%2C+J">Jia-Xin Peng</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+B">Baiqiang Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+W">Weiping Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Keye 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="2404.08436v2-abstract-short" style="display: inline;"> The detrimental impact of noise on sensing performance in quantum metrology has been widely recognized by researchers in the field. However, there are no explicit fundamental laws of physics stating that noise invariably weakens quantum metrology. We reveal that phase-covariant (PC) noise either degrades or remains neutral to sensing precision, whereas non-phase-covariant (NPC) noise can potential… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.08436v2-abstract-full').style.display = 'inline'; document.getElementById('2404.08436v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2404.08436v2-abstract-full" style="display: none;"> The detrimental impact of noise on sensing performance in quantum metrology has been widely recognized by researchers in the field. However, there are no explicit fundamental laws of physics stating that noise invariably weakens quantum metrology. We reveal that phase-covariant (PC) noise either degrades or remains neutral to sensing precision, whereas non-phase-covariant (NPC) noise can potentially enhance parameter estimation, surpassing even the ultimate precision limit achievable in the absence of noise. This implies that a non-Hermitian quantum sensor may outperform its Hermitian counterpart in terms of sensing performance. To illustrate and validate our theory, we present several paradigmatic examples of magnetic field metrology. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.08436v2-abstract-full').style.display = 'none'; document.getElementById('2404.08436v2-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">v1</span> submitted 12 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">19 pages, 5 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Physical Review Letters 133, 090801 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.15020">arXiv:2403.15020</a> <span> [<a href="https://arxiv.org/pdf/2403.15020">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Applied Physics">physics.app-ph</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/10.1002/aelm.202400041">10.1002/aelm.202400041 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> All van der Waals three-terminal SOT-MRAM realized by topological ferromagnet Fe3GeTe2 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Cui%2C+J">Jingyuan Cui</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kai-Xuan Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Park%2C+J">Je-Geun Park</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="2403.15020v2-abstract-short" style="display: inline;"> Magnetic van der Waals (vdW) materials have attracted massive attention because of their academic interest and application potential for the past few years. Its main advantage is the intrinsic two-dimensionality, enabling much smaller devices of novel concepts. One particular exciting direction lies in the current-driven spin-orbit torque (SOT). Here, we, for the first time, realize an all vdW thr… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.15020v2-abstract-full').style.display = 'inline'; document.getElementById('2403.15020v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.15020v2-abstract-full" style="display: none;"> Magnetic van der Waals (vdW) materials have attracted massive attention because of their academic interest and application potential for the past few years. Its main advantage is the intrinsic two-dimensionality, enabling much smaller devices of novel concepts. One particular exciting direction lies in the current-driven spin-orbit torque (SOT). Here, we, for the first time, realize an all vdW three-terminal SOT memory, employing the unique physics principle of gigantic intrinsic SOT of Fe3GeTe2 (FGT) and the well-known industry-adopted tunnelling magnetoresistance (TMR) effect. We designed the device operation procedure and fabricated the FGT/h-BN/FGT vdW heterostructure as a proof of concept. This device exhibits a classical TMR effect and unambiguously demonstrates the conception by precise performance as expected: the magnetic information of the top-FGT is written by current-driven SOT and read out by TMR separately. The writing and reading current paths are physically decoupled, enhancing the design and optimization flexibility substantially and further strengthening the device's endurance naturally. Our work would prompt more expansive use of vdW magnets for spintronic applications. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.15020v2-abstract-full').style.display = 'none'; document.getElementById('2403.15020v2-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 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 22 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">Accepted by Advanced Electronic Materials; 26 pages, 4 main figures, 3 supporting figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Advanced Electronic Materials 10, 2400041 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.11995">arXiv:2403.11995</a> <span> [<a href="https://arxiv.org/pdf/2403.11995">pdf</a>, <a href="https://arxiv.org/format/2403.11995">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"> Hamiltonian-reconstruction distance as a success metric for the Variational Quantum Eigensolver </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Moon%2C+L+J+I">Leo Joon Il Moon</a>, <a href="/search/quant-ph?searchtype=author&query=Sohoni%2C+M+M">Mandar M. Sohoni</a>, <a href="/search/quant-ph?searchtype=author&query=Shimizu%2C+M+A">Michael A. Shimizu</a>, <a href="/search/quant-ph?searchtype=author&query=Viswanathan%2C+P">Praveen Viswanathan</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kevin Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Kim%2C+E">Eun-Ah Kim</a>, <a href="/search/quant-ph?searchtype=author&query=McMahon%2C+P+L">Peter L. McMahon</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="2403.11995v1-abstract-short" style="display: inline;"> The Variational Quantum Eigensolver (VQE) is a hybrid quantum-classical algorithm for quantum simulation that can be run on near-term quantum hardware. A challenge in VQE -- as well as any other heuristic algorithm for finding ground states of Hamiltonians -- is to know how close the algorithm's output solution is to the true ground state, when the true ground state and ground-state energy are unk… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.11995v1-abstract-full').style.display = 'inline'; document.getElementById('2403.11995v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.11995v1-abstract-full" style="display: none;"> The Variational Quantum Eigensolver (VQE) is a hybrid quantum-classical algorithm for quantum simulation that can be run on near-term quantum hardware. A challenge in VQE -- as well as any other heuristic algorithm for finding ground states of Hamiltonians -- is to know how close the algorithm's output solution is to the true ground state, when the true ground state and ground-state energy are unknown. This is especially important in iterative algorithms, such as VQE, where one wants to avoid erroneous early termination. Recent developments in Hamiltonian reconstruction -- the inference of a Hamiltonian given an eigenstate -- give a metric can be used to assess the quality of a variational solution to a Hamiltonian-eigensolving problem. This metric can assess the proximity of the variational solution to the ground state without any knowledge of the true ground state or ground-state energy. In numerical simulations and in demonstrations on a cloud-based trapped-ion quantum computer, we show that for examples of both one-dimensional transverse-field-Ising (11 qubits) and two-dimensional J1-J2 transverse-field-Ising (6 qubits) spin problems, the Hamiltonian-reconstruction distance gives a helpful indication of whether VQE has yet found the ground state or not. Our experiments included cases where the energy plateaus as a function of the VQE iteration, which could have resulted in erroneous early stopping of the VQE algorithm, but where the Hamiltonian-reconstruction distance correctly suggests to continue iterating. We find that the Hamiltonian-reconstruction distance has a useful correlation with the fidelity between the VQE solution and the true ground state. Our work suggests that the Hamiltonian-reconstruction distance may be a useful tool for assessing success in VQE, including on noisy quantum processors in practice. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.11995v1-abstract-full').style.display = 'none'; document.getElementById('2403.11995v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 March, 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">18 pages, 15 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/2401.17586">arXiv:2401.17586</a> <span> [<a href="https://arxiv.org/pdf/2401.17586">pdf</a>, <a href="https://arxiv.org/format/2401.17586">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/10.1103/PhysRevB.109.104312">10.1103/PhysRevB.109.104312 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Magnetic Bloch oscillations in a non-Hermitian quantum Ising chain </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K+L">K. L. Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+Z">Z. Song</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="2401.17586v2-abstract-short" style="display: inline;"> We investigate the impacts of an imaginary transverse field on the dynamics of magnetic domain walls in a quantum Ising chain. We show that an imaginary field plays a similar role as a real transverse field in forming a low-lying Wannier-Stark ladder. However, analytical and numerical calculations of the time evolutions in both systems show that the corresponding Bloch oscillations exhibit totally… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.17586v2-abstract-full').style.display = 'inline'; document.getElementById('2401.17586v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2401.17586v2-abstract-full" style="display: none;"> We investigate the impacts of an imaginary transverse field on the dynamics of magnetic domain walls in a quantum Ising chain. We show that an imaginary field plays a similar role as a real transverse field in forming a low-lying Wannier-Stark ladder. However, analytical and numerical calculations of the time evolutions in both systems show that the corresponding Bloch oscillations exhibit totally different patterns for the same initial states. These findings reveal the nontrivial effect of non-Hermiticity on quantum spin dynamics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.17586v2-abstract-full').style.display = 'none'; document.getElementById('2401.17586v2-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 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 30 January, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">9 pages, 5 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 109, 104312 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2401.13286">arXiv:2401.13286</a> <span> [<a href="https://arxiv.org/pdf/2401.13286">pdf</a>, <a href="https://arxiv.org/format/2401.13286">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/1367-2630/ad9d70">10.1088/1367-2630/ad9d70 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Dynamics of non-Hermitian Floquet Wannier-Stark system </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+H+P">H. P. Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K+L">K. L. Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+Z">Z. Song</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="2401.13286v3-abstract-short" style="display: inline;"> We study the dynamics of the non-Hermitian Floquet Wannier-Stark system in the framework of the tight-binding approximation, where the hopping strength is a periodic function of time with Floquet frequency $蠅$. It is shown that the energy level of the instantaneous Hamiltonian is still equally spaced and independent of time $t$ and the Hermiticity of the hopping term. In the case of off resonance,… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.13286v3-abstract-full').style.display = 'inline'; document.getElementById('2401.13286v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2401.13286v3-abstract-full" style="display: none;"> We study the dynamics of the non-Hermitian Floquet Wannier-Stark system in the framework of the tight-binding approximation, where the hopping strength is a periodic function of time with Floquet frequency $蠅$. It is shown that the energy level of the instantaneous Hamiltonian is still equally spaced and independent of time $t$ and the Hermiticity of the hopping term. In the case of off resonance, the dynamics are still periodic, while the occupied energy levels spread out at the resonance, exhibiting $t^z$ behavior. Analytic analysis and numerical simulation show that the level-spreading dynamics for real and complex hopping strengths exhibit distinct behaviors and are well described by the dynamical exponents $z=1$ and $z=1/2$, respectively. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.13286v3-abstract-full').style.display = 'none'; document.getElementById('2401.13286v3-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 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 24 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">20 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/2312.14384">arXiv:2312.14384</a> <span> [<a href="https://arxiv.org/pdf/2312.14384">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Applied Physics">physics.app-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1002/adma.202312824">10.1002/adma.202312824 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Broken inversion symmetry in van der Waals topological ferromagnetic metal iron germanium telluride </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kai-Xuan Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Ju%2C+H">Hwiin Ju</a>, <a href="/search/quant-ph?searchtype=author&query=Kim%2C+H">Hyuncheol Kim</a>, <a href="/search/quant-ph?searchtype=author&query=Cui%2C+J">Jingyuan Cui</a>, <a href="/search/quant-ph?searchtype=author&query=Keum%2C+J">Jihoon Keum</a>, <a href="/search/quant-ph?searchtype=author&query=Park%2C+J">Je-Geun Park</a>, <a href="/search/quant-ph?searchtype=author&query=Lee%2C+J+S">Jong Seok Lee</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="2312.14384v2-abstract-short" style="display: inline;"> Inversion symmetry breaking is critical for many quantum effects and fundamental for spin-orbit torque, which is crucial for next-generation spintronics. Recently, a novel type of gigantic intrinsic spin-orbit torque has been established in the topological van-der-Waals (vdW) magnet iron germanium telluride. However, it remains a puzzle because no clear evidence exists for interlayer inversion sym… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.14384v2-abstract-full').style.display = 'inline'; document.getElementById('2312.14384v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2312.14384v2-abstract-full" style="display: none;"> Inversion symmetry breaking is critical for many quantum effects and fundamental for spin-orbit torque, which is crucial for next-generation spintronics. Recently, a novel type of gigantic intrinsic spin-orbit torque has been established in the topological van-der-Waals (vdW) magnet iron germanium telluride. However, it remains a puzzle because no clear evidence exists for interlayer inversion symmetry breaking. Here, we report the definitive evidence of broken inversion symmetry in iron germanium telluride directly measured by the second harmonic generation (SHG) technique. Our data show that the crystal symmetry reduces from centrosymmetric P63/mmc to noncentrosymmetric polar P3m1 space group, giving the three-fold SHG pattern with dominant out-of-plane polarization. Additionally, the SHG response evolves from an isotropic pattern to a sharp three-fold symmetry upon increasing Fe deficiency, mainly due to the transition from random defects to ordered Fe vacancies. Such SHG response is robust against temperature, ensuring unaltered crystalline symmetries above and below the ferromagnetic transition temperature. These findings add crucial new information to our understanding of this interesting vdW metal, iron germanium telluride: band topology, intrinsic spin-orbit torque and topological vdW polar metal states. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.14384v2-abstract-full').style.display = 'none'; document.getElementById('2312.14384v2-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 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 21 December, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted by Advanced Materials; 32 pages, 4 main figures, 5 supporting figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Advanced Materials 36, 2312824 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2312.13444">arXiv:2312.13444</a> <span> [<a href="https://arxiv.org/pdf/2312.13444">pdf</a>, <a href="https://arxiv.org/format/2312.13444">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.109.012204">10.1103/PhysRevA.109.012204 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Optimal energy storage in the Tavis-Cummings quantum battery </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Yang%2C+H">Hui-Yu Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Shi%2C+H">Hai-Long Shi</a>, <a href="/search/quant-ph?searchtype=author&query=Wan%2C+Q">Qing-Kun Wan</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kun Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+X">Xiao-Hui Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+W">Wen-Li Yang</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="2312.13444v2-abstract-short" style="display: inline;"> The Tavis-Cummings (TC) model, which serves as a natural physical realization of a quantum battery, comprises $N_b$ atoms as battery cells that collectively interact with a shared photon field, functioning as the charger, initially containing $n_0$ photons. In this study, we introduce the invariant subspace method to effectively represent the quantum dynamics of the TC battery. Our findings indica… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.13444v2-abstract-full').style.display = 'inline'; document.getElementById('2312.13444v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2312.13444v2-abstract-full" style="display: none;"> The Tavis-Cummings (TC) model, which serves as a natural physical realization of a quantum battery, comprises $N_b$ atoms as battery cells that collectively interact with a shared photon field, functioning as the charger, initially containing $n_0$ photons. In this study, we introduce the invariant subspace method to effectively represent the quantum dynamics of the TC battery. Our findings indicate that in the limiting case of $n_0\!\gg\! N_b$ or $N_b\!\gg\! n_0$, a distinct SU(2) symmetry emerges in the dynamics, thereby ensuring the realization of optimal energy storage. We also establish a negative relationship between the battery-charger entanglement and the energy storage capacity. As a result, we demonstrate that the asymptotically optimal energy storage can be achieved in the scenario where $N_b\!=\!n_0\!\gg\! 1$. Our approach not only enhances our comprehension of the algebraic structure inherent in the TC model but also contributes to the broader theoretical framework of quantum batteries. Furthermore, it provides crucial insights into the relation between energy transfer and quantum correlations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.13444v2-abstract-full').style.display = 'none'; document.getElementById('2312.13444v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 8 January, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 20 December, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">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. A 109, 012204 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2311.16868">arXiv:2311.16868</a> <span> [<a href="https://arxiv.org/pdf/2311.16868">pdf</a>, <a href="https://arxiv.org/format/2311.16868">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 Gases">cond-mat.quant-gas</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Two-dimensional Asymptotic Generalized Brillouin Zone Theory </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Xu%2C+Z">Zeqi Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Pang%2C+B">Bo Pang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kai Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+Z">Zhesen Yang</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="2311.16868v2-abstract-short" style="display: inline;"> In this work, we propose a theory on the two-dimensional non-Hermitian skin effect by resolving two representative minimal models. Specifically, we show that for any given non-Hermitian Hamiltonian, (i) the corresponding region covered by its open boundary spectrum on the complex energy plane should be independent of the open boundary geometry; and (ii) for any given open boundary eigenvalue… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.16868v2-abstract-full').style.display = 'inline'; document.getElementById('2311.16868v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2311.16868v2-abstract-full" style="display: none;"> In this work, we propose a theory on the two-dimensional non-Hermitian skin effect by resolving two representative minimal models. Specifically, we show that for any given non-Hermitian Hamiltonian, (i) the corresponding region covered by its open boundary spectrum on the complex energy plane should be independent of the open boundary geometry; and (ii) for any given open boundary eigenvalue $E_0$ , its corresponding two-dimensional asymptotic generalized Brillouin zone is determined by a series of geometry-independent Bloch/non-Bloch Fermi points and geometry-dependent non-Bloch equal frequency contours that connect them. A corollary of our theory is that most symmetry-protected exceptional semimetals should be robust to variations in OBC geometry. Our theory paves the way to the discussion on the higher dimensional non-Bloch band theory and the corresponding non-Hermitian bulk-boundary correspondence. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.16868v2-abstract-full').style.display = 'none'; document.getElementById('2311.16868v2-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 28 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">7 pages, 3 figures, including appendix</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2311.05166">arXiv:2311.05166</a> <span> [<a href="https://arxiv.org/pdf/2311.05166">pdf</a>, <a href="https://arxiv.org/format/2311.05166">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/10.1007/s11467-023-1364-5">10.1007/s11467-023-1364-5 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Charge qubits based on ultra-thin topological insulator films </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kexin Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Lepage%2C+H+V">Hugo V. Lepage</a>, <a href="/search/quant-ph?searchtype=author&query=Dong%2C+Y">Ying Dong</a>, <a href="/search/quant-ph?searchtype=author&query=Barnes%2C+C+H+W">Crispin H. W. Barnes</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="2311.05166v1-abstract-short" style="display: inline;"> We study how to use the surface states in a Bi$_{2}$Se$_{3}$ topological insulator ultra-thin film that are affected by finite size effects for the purpose of quantum computing. We demonstrate that: (i) surface states under the finite size effect can effectively form a two-level system where their energy levels lie in between the bulk energy gap and a logic qubit can be constructed, (ii) the qubit… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.05166v1-abstract-full').style.display = 'inline'; document.getElementById('2311.05166v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2311.05166v1-abstract-full" style="display: none;"> We study how to use the surface states in a Bi$_{2}$Se$_{3}$ topological insulator ultra-thin film that are affected by finite size effects for the purpose of quantum computing. We demonstrate that: (i) surface states under the finite size effect can effectively form a two-level system where their energy levels lie in between the bulk energy gap and a logic qubit can be constructed, (ii) the qubit can be initialized and manipulated using electric pulses of simple forms, (iii) two-qubit entanglement is achieved through a $\sqrt{\text{SWAP}}$ operation when the two qubits are in a parallel setup, and (iv) alternatively, a Floquet state can be exploited to construct a qubit and two Floquet qubits can be entangled through a Controlled-NOT operation. The Floquet qubit offers robustness to background noise since there is always an oscillating electric field applied, and the single qubit operations are controlled by amplitude modulation of the oscillating field, which is convenient experimentally. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.05166v1-abstract-full').style.display = 'none'; document.getElementById('2311.05166v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 9 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">12 pages, 9 figures, submitted to the journal Frontiers of Physics</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2311.04864">arXiv:2311.04864</a> <span> [<a href="https://arxiv.org/pdf/2311.04864">pdf</a>, <a href="https://arxiv.org/format/2311.04864">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> <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"> Realization of programmable Ising models in a trapped-ion quantum simulator </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Lu%2C+Y">Yao Lu</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+W">Wentao Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+S">Shuaining Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kuan Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+J">Jialiang Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+J">Jing-Ning Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Kim%2C+K">Kihwan Kim</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="2311.04864v1-abstract-short" style="display: inline;"> A promising paradigm of quantum computing for achieving practical quantum advantages is quantum annealing or quantum approximate optimization algorithm, where the classical problems are encoded in Ising interactions. However, it is challenging to build a quantum system that can efficiently map any structured problems. Here, we present a programmable trapped-ion quantum simulator of an Ising model… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.04864v1-abstract-full').style.display = 'inline'; document.getElementById('2311.04864v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2311.04864v1-abstract-full" style="display: none;"> A promising paradigm of quantum computing for achieving practical quantum advantages is quantum annealing or quantum approximate optimization algorithm, where the classical problems are encoded in Ising interactions. However, it is challenging to build a quantum system that can efficiently map any structured problems. Here, we present a programmable trapped-ion quantum simulator of an Ising model with all-to-all connectivity with up to four spins. We implement the spin-spin interactions by using the coupling of trapped ions to multiple collective motional modes and realize the programmability through phase modulation of the Raman laser beams that are individually addressed on ions. As an example, we realize several Ising lattices with different interaction connectivities, where the interactions can be ferromagnetic or anti-ferromagnetic. We confirm the programmed interaction geometry by observing the ground states of the corresponding models through quantum state tomography. Our experimental demonstrations serve as an important basis for realizing practical quantum advantages with trapped ions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.04864v1-abstract-full').style.display = 'none'; document.getElementById('2311.04864v1-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 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">11 pages, 7 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/2310.19348">arXiv:2310.19348</a> <span> [<a href="https://arxiv.org/pdf/2310.19348">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Rapid suppression of quantum many-body magnetic exciton in doped van der Waals antiferromagnet (Ni,Cd)PS3 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Kim%2C+J">Junghyun Kim</a>, <a href="/search/quant-ph?searchtype=author&query=Na%2C+W">Woongki Na</a>, <a href="/search/quant-ph?searchtype=author&query=Kim%2C+J">Jonghyeon Kim</a>, <a href="/search/quant-ph?searchtype=author&query=Park%2C+P">Pyeongjae Park</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kaixuan Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Hwang%2C+I">Inho Hwang</a>, <a href="/search/quant-ph?searchtype=author&query=Son%2C+Y">Young-Woo Son</a>, <a href="/search/quant-ph?searchtype=author&query=Kim%2C+J+H">Jae Hoon Kim</a>, <a href="/search/quant-ph?searchtype=author&query=Cheong%2C+H">Hyeonsik Cheong</a>, <a href="/search/quant-ph?searchtype=author&query=Park%2C+J">Je-Geun Park</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="2310.19348v1-abstract-short" style="display: inline;"> The unique discovery of magnetic exciton in van der Waals antiferromagnet NiPS3 arises between two quantum many-body states of a Zhang-Rice singlet excited state and a Zhang-Rice triplet ground state. Simultaneously, the spectral width of photoluminescence originating from this exciton is exceedingly narrow as 0.4 meV. These extraordinary properties, including the extreme coherence of the magnetic… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.19348v1-abstract-full').style.display = 'inline'; document.getElementById('2310.19348v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2310.19348v1-abstract-full" style="display: none;"> The unique discovery of magnetic exciton in van der Waals antiferromagnet NiPS3 arises between two quantum many-body states of a Zhang-Rice singlet excited state and a Zhang-Rice triplet ground state. Simultaneously, the spectral width of photoluminescence originating from this exciton is exceedingly narrow as 0.4 meV. These extraordinary properties, including the extreme coherence of the magnetic exciton in NiPS3, beg many questions. We studied doping effects using Ni1-xCdxPS3 using two experimental techniques and theoretical studies. Our experimental results show that the magnetic exciton is drastically suppressed upon a few % Cd doping. All these happen while the width of the exciton only gradually increases, and the antiferromagnetic ground state is robust. These results highlight the lattice uniformity's hidden importance as a prerequisite for coherent magnetic exciton. Finally, an exciting scenario emerges: the broken charge transfer forbids the otherwise uniform formation of the coherent magnetic exciton in (Ni,Cd)PS3. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.19348v1-abstract-full').style.display = 'none'; document.getElementById('2310.19348v1-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 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">40 pages, 4 main figures, 13 supporting figures, accepted by Nano Letters</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2310.05412">arXiv:2310.05412</a> <span> [<a href="https://arxiv.org/pdf/2310.05412">pdf</a>, <a href="https://arxiv.org/ps/2310.05412">ps</a>, <a href="https://arxiv.org/format/2310.05412">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"> Estimation theory of photon-magnon coupling strength in a driven-dissipative double-cavity-magnon system </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Peng%2C+J">Jia-Xin Peng</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+B">Baiqiang Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+W">Weiping Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Keye 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="2310.05412v1-abstract-short" style="display: inline;"> Cavity-magnon systems are emerging as a fruitful architecture for the integration of quantum technologies and spintronic technologies, where magnons are coupled to microwave photons via the magnetic-dipole interaction. Controllable the photon-magnon (P-M) couplings provide a powerful means of accessing and manipulating quantum states in such hybrid systems. Thus determining the relevant P-M coupli… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.05412v1-abstract-full').style.display = 'inline'; document.getElementById('2310.05412v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2310.05412v1-abstract-full" style="display: none;"> Cavity-magnon systems are emerging as a fruitful architecture for the integration of quantum technologies and spintronic technologies, where magnons are coupled to microwave photons via the magnetic-dipole interaction. Controllable the photon-magnon (P-M) couplings provide a powerful means of accessing and manipulating quantum states in such hybrid systems. Thus determining the relevant P-M couplings is a fundamental task. Here we address the quantum estimation problem for the P-M coupling strength in a double-cavity-magnon system with drive and dissipation. The effects of various physical factors on the estimation precision are investigated and the underlying physical mechanisms are discussed in detail. Considering that in practical experiments it is almost infeasible to perform measurements on the global quantum state of this composite system, we identify the optimal subsystem for performing measurements and estimations. Further, we evaluate the performance of different Gaussian measurements, indicating that optimal Gaussian measurement almost saturates the ultimate theoretical bound on the estimation precision given by the quantum Fisher information. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.05412v1-abstract-full').style.display = 'none'; document.getElementById('2310.05412v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 9 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">16 pages, 7 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/2309.03950">arXiv:2309.03950</a> <span> [<a href="https://arxiv.org/pdf/2309.03950">pdf</a>, <a href="https://arxiv.org/format/2309.03950">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 Gases">cond-mat.quant-gas</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.109.165127">10.1103/PhysRevB.109.165127 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Edge theory of non-Hermitian skin modes in higher dimensions </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kai Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+Z">Zhesen Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Sun%2C+K">Kai Sun</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="2309.03950v3-abstract-short" style="display: inline;"> In this paper, we establish an effective edge theory to characterize non-Hermitian edge-skin modes in higher dimensions. We begin by proposing a bulk projection criterion to straightforwardly identify the localized edges of skin modes. Through an exact mapping, we show that the edge-skin mode shares the same bulk-boundary correspondence and localization characteristics as the zero-energy edge stat… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.03950v3-abstract-full').style.display = 'inline'; document.getElementById('2309.03950v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2309.03950v3-abstract-full" style="display: none;"> In this paper, we establish an effective edge theory to characterize non-Hermitian edge-skin modes in higher dimensions. We begin by proposing a bulk projection criterion to straightforwardly identify the localized edges of skin modes. Through an exact mapping, we show that the edge-skin mode shares the same bulk-boundary correspondence and localization characteristics as the zero-energy edge states in a Hermitian semimetal under open-boundary conditions, bridging the gap between non-Hermitian edge-skin effect and Hermitian semimetals. Another key finding is the introduction of ``skewness,'' a term we proposed to describe the characteristic decay direction of skin mode from the localized edge into the bulk. Remarkably, we demonstrate that skewness is an intrinsic quantity of the skin mode and can be analytically determined using the corresponding cylinder-geometry bulk Hamiltonian, without requiring any boundary details. Furthermore, we reveal that in the edge-skin effect, the spectrum exhibits anomalous spectral sensitivity to weak local disturbances, a feature that crucially distinguishes it from the corner-skin effect. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.03950v3-abstract-full').style.display = 'none'; document.getElementById('2309.03950v3-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 April, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 7 September, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 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">15 pages, 10 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 109, 165127 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2309.01917">arXiv:2309.01917</a> <span> [<a href="https://arxiv.org/pdf/2309.01917">pdf</a>, <a href="https://arxiv.org/format/2309.01917">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Theory">hep-th</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</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"> Page Time as a Transition of Information Channels: High-fidelity Information Retrieval for Radiating Black Holes </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+R">Ran Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+X">Xuanhua Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kun Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+J">Jin 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="2309.01917v2-abstract-short" style="display: inline;"> The effective field theory description of a radiating black hole introduces redundant degrees of freedom that necessitate annihilation of those modes at late stages to conserve entropy. The prevailing view is that such effective process can result in information loss unless the redundant states are annihilated in maximally entangled pairs, resembling quantum teleportation. In this Letter, we demon… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.01917v2-abstract-full').style.display = 'inline'; document.getElementById('2309.01917v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2309.01917v2-abstract-full" style="display: none;"> The effective field theory description of a radiating black hole introduces redundant degrees of freedom that necessitate annihilation of those modes at late stages to conserve entropy. The prevailing view is that such effective process can result in information loss unless the redundant states are annihilated in maximally entangled pairs, resembling quantum teleportation. In this Letter, we demonstrate that this view can be relaxed in a new postselection model. We investigate information recoverability in a radiating black hole through the non-unitary dynamics that projects the randomly-selected modes from a scrambling unitary. We show that the model has the merit of producing the von Neumann entropy of black holes consistent with the island formula calculation and that information in the black hole interior can be decoded from the Hawking radiation without loss after the Page time. Moreover, in this model the Page time gains a new interpretation as the transition point between two channels of information transmission when sufficient amounts of effective modes are annihilated inside the horizon. We present two decoding strategies along with their quantum circuit realizations. The experimental verification of the strategies employs 7-qubit IBM quantum processors, demonstrating the viability of these strategies and the potential for quantum processors to probe the black hole interior. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.01917v2-abstract-full').style.display = 'none'; document.getElementById('2309.01917v2-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 December, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 4 September, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 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">5 pages. Short version of arXiv:2307.01454</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2308.10183">arXiv:2308.10183</a> <span> [<a href="https://arxiv.org/pdf/2308.10183">pdf</a>, <a href="https://arxiv.org/ps/2308.10183">ps</a>, <a href="https://arxiv.org/format/2308.10183">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"> Dissipative quantum Fisher information for a general Liouvillian parameterized process </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Peng%2C+J">Jia-Xin Peng</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+B">Baiqiang Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+W">Weiping Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Keye 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="2308.10183v1-abstract-short" style="display: inline;"> The dissipative quantum Fisher information (DQFI) for a dynamic map with a general parameter in an open quantum system is investigated, which can be regarded as an analog of the quantum Fisher information (QFI) in the Liouville space. We first derive a general dissipative generator in the Liouville space, and based on its decomposition form, find the DQFI stems from two parts. One is the dependenc… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.10183v1-abstract-full').style.display = 'inline'; document.getElementById('2308.10183v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2308.10183v1-abstract-full" style="display: none;"> The dissipative quantum Fisher information (DQFI) for a dynamic map with a general parameter in an open quantum system is investigated, which can be regarded as an analog of the quantum Fisher information (QFI) in the Liouville space. We first derive a general dissipative generator in the Liouville space, and based on its decomposition form, find the DQFI stems from two parts. One is the dependence of eigenvalues of the Liouvillian supermatrix on the estimated parameter, which shows a linear dependence on time. The other is the variation of the eigenvectors with the estimated parameter. The relationship between this part and time presents rich characteristics, including harmonic oscillation, pure exponential gain and attenuation, as well as exponential gain and attenuation of oscillatory type, which depend specifically on the properties of the Liouville spectrum. This is in contrast to that of the conventional generator, where only oscillatory dependencies are seen. Further, we illustrate the theory through a toy model: a two-level system with spin-flip noise. Especially, by using the DQFI, we demonstrated that the exceptional estimation precision cannot be obtained at the Liouvillian exceptional point. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.10183v1-abstract-full').style.display = 'none'; document.getElementById('2308.10183v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 20 August, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 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">22 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/2308.03002">arXiv:2308.03002</a> <span> [<a href="https://arxiv.org/pdf/2308.03002">pdf</a>, <a href="https://arxiv.org/ps/2308.03002">ps</a>, <a href="https://arxiv.org/format/2308.03002">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"> The effect of Quantum Statistics on the sensitivity in an SU(1,1) interferometer </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zeng%2C+J">Jie Zeng</a>, <a href="/search/quant-ph?searchtype=author&query=Ding%2C+Y">Yingxing Ding</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+M">Mengyao Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Jiao%2C+G">Gao-Feng Jiao</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Keye Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+L+Q">L. Q. Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+W">Weiping Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Yuan%2C+C">Chun-Hua Yuan</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="2308.03002v1-abstract-short" style="display: inline;"> We theoretically study the effect of quantum statistics of the light field on the quantum enhancement of parameter estimation based on cat state input the SU(1,1) interferometer. The phase sensitivity is dependent on the relative phase $胃$ between two coherent states of Schr枚dinger cat states. The optimal sensitivity is achieved when the relative phase is $蟺$% , i.e., odd coherent states input. Fo… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.03002v1-abstract-full').style.display = 'inline'; document.getElementById('2308.03002v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2308.03002v1-abstract-full" style="display: none;"> We theoretically study the effect of quantum statistics of the light field on the quantum enhancement of parameter estimation based on cat state input the SU(1,1) interferometer. The phase sensitivity is dependent on the relative phase $胃$ between two coherent states of Schr枚dinger cat states. The optimal sensitivity is achieved when the relative phase is $蟺$% , i.e., odd coherent states input. For a coherent state input into one port, the phase sensitivity of the odd coherent state into the second input port is inferior to that of the squeezed vacuum state input. However, in the presence of losses the Schr枚dinger cat states are more resistant to loss than squeezed vacuum states. As the amplitude of Schr枚dinger cat states increases, the quantum enhancement of phase sensitivity decreases, which shows that the quantum statistics of Schr枚dinger cat states tends towards Poisson statistics from sub-Poisson statistics or super-Poisson statistics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.03002v1-abstract-full').style.display = 'none'; document.getElementById('2308.03002v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 August, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 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">8 pages, 5 figures. arXiv admin note: text overlap with arXiv:2302.09823</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2307.16781">arXiv:2307.16781</a> <span> [<a href="https://arxiv.org/pdf/2307.16781">pdf</a>, <a href="https://arxiv.org/format/2307.16781">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="Mathematical Physics">math-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1002/qute.202300345">10.1002/qute.202300345 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Optimal realization of Yang-Baxter gate on quantum computers </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kun Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Yu%2C+K">Kwangmin Yu</a>, <a href="/search/quant-ph?searchtype=author&query=Hao%2C+K">Kun Hao</a>, <a href="/search/quant-ph?searchtype=author&query=Korepin%2C+V">Vladimir Korepin</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2307.16781v3-abstract-short" style="display: inline;"> Quantum computers provide a promising method to study the dynamics of many-body systems beyond classical simulation. On the other hand, the analytical methods developed and results obtained from the integrable systems provide deep insights on the many-body system. Quantum simulation of the integrable system not only provides a valid benchmark for quantum computers but is also the first step in stu… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2307.16781v3-abstract-full').style.display = 'inline'; document.getElementById('2307.16781v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2307.16781v3-abstract-full" style="display: none;"> Quantum computers provide a promising method to study the dynamics of many-body systems beyond classical simulation. On the other hand, the analytical methods developed and results obtained from the integrable systems provide deep insights on the many-body system. Quantum simulation of the integrable system not only provides a valid benchmark for quantum computers but is also the first step in studying integrable-breaking systems. The building block for the simulation of an integrable system is the Yang-Baxter gate. It is vital to know how to optimally realize the Yang-Baxter gates on quantum computers. Based on the geometric picture of the Yang-Baxter gates, we present the optimal realizations of two types of Yang-Baxter gates with a minimal number of CNOT or $R_{zz}$ gates. We also show how to systematically realize the Yang-Baxter gates via the pulse control. We test and compare the different realizations on IBM quantum computers. We find that the pulse realizations of the Yang-Baxter gates always have a higher gate fidelity compared to the optimal CNOT or $R_{zz}$ realizations. On the basis of the above optimal realizations, we demonstrate the simulation of the Yang-Baxter equation on quantum computers. Our results provide a guideline and standard for further experimental studies based on the Yang-Baxter gate. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2307.16781v3-abstract-full').style.display = 'none'; document.getElementById('2307.16781v3-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 February, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 31 July, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Published version, 14 pages, 11 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Adv. Quantum Technol. 2024, 2300345 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2307.08737">arXiv:2307.08737</a> <span> [<a href="https://arxiv.org/pdf/2307.08737">pdf</a>, <a href="https://arxiv.org/format/2307.08737">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevX.14.011051">10.1103/PhysRevX.14.011051 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Demonstrating a long-coherence dual-rail erasure qubit using tunable transmons </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Levine%2C+H">Harry Levine</a>, <a href="/search/quant-ph?searchtype=author&query=Haim%2C+A">Arbel Haim</a>, <a href="/search/quant-ph?searchtype=author&query=Hung%2C+J+S+C">Jimmy S. C. Hung</a>, <a href="/search/quant-ph?searchtype=author&query=Alidoust%2C+N">Nasser Alidoust</a>, <a href="/search/quant-ph?searchtype=author&query=Kalaee%2C+M">Mahmoud Kalaee</a>, <a href="/search/quant-ph?searchtype=author&query=DeLorenzo%2C+L">Laura DeLorenzo</a>, <a href="/search/quant-ph?searchtype=author&query=Wollack%2C+E+A">E. Alex Wollack</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=Khalajhedayati%2C+A">Amirhossein Khalajhedayati</a>, <a href="/search/quant-ph?searchtype=author&query=Sanil%2C+R">Rohan Sanil</a>, <a href="/search/quant-ph?searchtype=author&query=Moradinejad%2C+H">Hesam Moradinejad</a>, <a href="/search/quant-ph?searchtype=author&query=Vaknin%2C+Y">Yotam Vaknin</a>, <a href="/search/quant-ph?searchtype=author&query=Kubica%2C+A">Aleksander Kubica</a>, <a href="/search/quant-ph?searchtype=author&query=Hover%2C+D">David Hover</a>, <a href="/search/quant-ph?searchtype=author&query=Aghaeimeibodi%2C+S">Shahriar Aghaeimeibodi</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=Baek%2C+C">Christopher Baek</a>, <a href="/search/quant-ph?searchtype=author&query=Barnett%2C+J">James Barnett</a>, <a href="/search/quant-ph?searchtype=author&query=Bawdekar%2C+K">Kaustubh Bawdekar</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">Hugh 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>, <a href="/search/quant-ph?searchtype=author&query=Chinkezian%2C+H">Harut Chinkezian</a>, <a href="/search/quant-ph?searchtype=author&query=Chisholm%2C+E+M">Eric M. Chisholm</a> , et al. (88 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="2307.08737v3-abstract-short" style="display: inline;"> Quantum error correction with erasure qubits promises significant advantages over standard error correction due to favorable thresholds for erasure errors. To realize this advantage in practice requires a qubit for which nearly all errors are such erasure errors, and the ability to check for erasure errors without dephasing the qubit. We demonstrate that a "dual-rail qubit" consisting of a pair of… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2307.08737v3-abstract-full').style.display = 'inline'; document.getElementById('2307.08737v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2307.08737v3-abstract-full" style="display: none;"> Quantum error correction with erasure qubits promises significant advantages over standard error correction due to favorable thresholds for erasure errors. To realize this advantage in practice requires a qubit for which nearly all errors are such erasure errors, and the ability to check for erasure errors without dephasing the qubit. We demonstrate that a "dual-rail qubit" consisting of a pair of resonantly coupled transmons can form a highly coherent erasure qubit, where transmon $T_1$ errors are converted into erasure errors and residual dephasing is strongly suppressed, leading to millisecond-scale coherence within the qubit subspace. We show that single-qubit gates are limited primarily by erasure errors, with erasure probability $p_\text{erasure} = 2.19(2)\times 10^{-3}$ per gate while the residual errors are $\sim 40$ times lower. We further demonstrate mid-circuit detection of erasure errors while introducing $< 0.1\%$ dephasing error per check. Finally, we show that the suppression of transmon noise allows this dual-rail qubit to preserve high coherence over a broad tunable operating range, offering an improved capacity to avoid frequency collisions. This work establishes transmon-based dual-rail qubits as an attractive building block for hardware-efficient quantum error correction. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2307.08737v3-abstract-full').style.display = 'none'; document.getElementById('2307.08737v3-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 17 July, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">9+13 pages, 16 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Physical Review X 14, 011051 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2307.01454">arXiv:2307.01454</a> <span> [<a href="https://arxiv.org/pdf/2307.01454">pdf</a>, <a href="https://arxiv.org/format/2307.01454">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Theory">hep-th</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</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"> Information retrieval from Hawking radiation in the non-isometric model of black hole interior: theory and quantum simulations </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+R">Ran Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+X">Xuanhua Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kun Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+J">Jin 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="2307.01454v3-abstract-short" style="display: inline;"> The non-isometric holographic model of the black hole interior stands out as a potential resolution of the long-standing black hole information puzzle since it remedies the friction between the effective calculation and the microscopic description. In this study, combining the final-state projection model, the non-isometric model of black hole interior and Hayden-Preskill thought experiment, we in… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2307.01454v3-abstract-full').style.display = 'inline'; document.getElementById('2307.01454v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2307.01454v3-abstract-full" style="display: none;"> The non-isometric holographic model of the black hole interior stands out as a potential resolution of the long-standing black hole information puzzle since it remedies the friction between the effective calculation and the microscopic description. In this study, combining the final-state projection model, the non-isometric model of black hole interior and Hayden-Preskill thought experiment, we investigate the information recovery from decoding Hawking radiation and demonstrate the emergence of the Page time in this setup. We incorporate the effective modes into the scrambling inside the horizon, which are usually disregarded in Hayden-Preskill protocols, and show that the Page time can be identified as the transition of information transmission channels from the EPR projection to the local projections. This offers a new perspective on the Page time. We compute the decoupling condition under which retrieving information is feasible and show that this model computes the black hole entropy consistent with the quantum extremal surface calculation. Assuming the full knowledge of the dynamics of the black hole interior, we show how Yoshida-Kitaev decoding strategy can be employed in the modified Hayden-Preskill protocol. Furthermore, we perform experimental tests of both probabilistic and Grover's search decoding strategies on the 7-qubit IBM quantum processors to validate our analytical findings and confirm the feasibility of retrieving information in the non-isometric model. This study would stimulate more interests to explore black hole information problem on the quantum processors. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2307.01454v3-abstract-full').style.display = 'none'; document.getElementById('2307.01454v3-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 January, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 3 July, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">47 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/2306.14099">arXiv:2306.14099</a> <span> [<a href="https://arxiv.org/pdf/2306.14099">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Detectors">physics.ins-det</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</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"> High-precision and low-latency widefield diamond quantum sensing with neuromorphic vision sensors </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Du%2C+Z">Zhiyuan Du</a>, <a href="/search/quant-ph?searchtype=author&query=Gupta%2C+M">Madhav Gupta</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+F">Feng Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kai Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+J">Jiahua Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Y">Yan Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+Y">Yiyao Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zhenyu Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Wrachtrup%2C+J">Jorg Wrachtrup</a>, <a href="/search/quant-ph?searchtype=author&query=Wong%2C+N">Ngai Wong</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+C">Can Li</a>, <a href="/search/quant-ph?searchtype=author&query=Chu%2C+Z">Zhiqin Chu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2306.14099v1-abstract-short" style="display: inline;"> During the past decade, interest has grown significantly in developing ultrasensitive widefield diamond magnetometry for various applications. Despite attempts to improve the adoption of conventional frame-based sensors, achieving high temporal resolution and sensitivity simultaneously remains a key challenge. This is largely due to the transfer and processing of massive amounts of sensor data to… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.14099v1-abstract-full').style.display = 'inline'; document.getElementById('2306.14099v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2306.14099v1-abstract-full" style="display: none;"> During the past decade, interest has grown significantly in developing ultrasensitive widefield diamond magnetometry for various applications. Despite attempts to improve the adoption of conventional frame-based sensors, achieving high temporal resolution and sensitivity simultaneously remains a key challenge. This is largely due to the transfer and processing of massive amounts of sensor data to capture the widefield fluorescence intensity changes of spin defects in diamonds. In this study, we adopt a neuromorphic vision sensor to address this issue. This sensor pre-processes the detected signals in optically detected magnetic resonance (ODMR) measurements for quantum sensing, employing a working principle that closely resembles the operation of the human vision system. By encoding the changes of light intensity into spikes, this approach results in a vast dynamic range, high temporal resolution, and exceptional signal-to-background ratio. After a thorough evaluation of theoretical feasibility, our experiment with an off-the-shelf event camera demonstrated a 13x improvement in temporal resolution with comparable precision of detecting ODMR resonance frequencies compared with the state-of-the-art highly specialized frame-based approach. A specialized camera system with the same mechanism has the potential to enhance these benefits further. This performance improvement is primarily attributable to orders of magnitude smaller data volumes and, thus, reduced latency. We further showcase the deployment of this technology in monitoring dynamically modulated laser heating of gold nanoparticles coated on a diamond surface, a recognizably difficult task using existing approaches. The current development provides new insights for high-precision and low-latency widefield quantum sensing, with possibilities for integration with emerging memory devices for more efficient event-based data processing. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.14099v1-abstract-full').style.display = 'none'; document.getElementById('2306.14099v1-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 June, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">21 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/2306.14065">arXiv:2306.14065</a> <span> [<a href="https://arxiv.org/pdf/2306.14065">pdf</a>, <a href="https://arxiv.org/format/2306.14065">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Topologically Protected Exceptional Points and Reentrant $\mathcal{PT}$ Phase in an Exact Ternary Model </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Lee%2C+C">Chulwon Lee</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kai Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Miao%2C+J">Jinyan Miao</a>, <a href="/search/quant-ph?searchtype=author&query=Sun%2C+K">Kai Sun</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+H">Hui Deng</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2306.14065v2-abstract-short" style="display: inline;"> In open, driven systems where parity-time symmetry is preserved, phenomena that defy conventional wisdom emerge near exceptional points, promising advances in photonics. While most studies focus on two-level systems of a conventional exceptional point, unconventional exceptional points as well as reentrant phases have been discovered in separate studies of higher-dimensional phase spaces. In this… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.14065v2-abstract-full').style.display = 'inline'; document.getElementById('2306.14065v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2306.14065v2-abstract-full" style="display: none;"> In open, driven systems where parity-time symmetry is preserved, phenomena that defy conventional wisdom emerge near exceptional points, promising advances in photonics. While most studies focus on two-level systems of a conventional exceptional point, unconventional exceptional points as well as reentrant phases have been discovered in separate studies of higher-dimensional phase spaces. In this Letter, we present a minimal, analytical model that encompasses several key phenomena in higher-dimensional phase spaces, including reentrant PT phases, higher-order exceptional points, and anisotropic exceptional points. Using the exact analytical solution, we identify a new topological index as the unifying origin of these different phenomena. The simplicity of the model may furthermore facilitate experimental implementations for enhanced sensing and efficient polariton devices. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.14065v2-abstract-full').style.display = 'none'; document.getElementById('2306.14065v2-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 January, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 24 June, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">12 pages, 7 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/2306.10000">arXiv:2306.10000</a> <span> [<a href="https://arxiv.org/pdf/2306.10000">pdf</a>, <a href="https://arxiv.org/format/2306.10000">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/PhysRevB.109.184302">10.1103/PhysRevB.109.184302 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Loss-induced universal one-way transport in periodically driven systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Shu%2C+C">Chang Shu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kai Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Sun%2C+K">Kai Sun</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2306.10000v2-abstract-short" style="display: inline;"> In this paper, we show that a periodically driven Aubry-Andr茅-Harper model with imbalanced on-site gain/loss supports universal one-way transport that is immune to impurities and independent of initial excitations. We reveal the underlying mechanism that the periodic driving gives rise to the non-Hermitian skin effect in the effective Floquet Hamiltonian, thereby causing universal non-reciprocal t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.10000v2-abstract-full').style.display = 'inline'; document.getElementById('2306.10000v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2306.10000v2-abstract-full" style="display: none;"> In this paper, we show that a periodically driven Aubry-Andr茅-Harper model with imbalanced on-site gain/loss supports universal one-way transport that is immune to impurities and independent of initial excitations. We reveal the underlying mechanism that the periodic driving gives rise to the non-Hermitian skin effect in the effective Floquet Hamiltonian, thereby causing universal non-reciprocal transport. Additionally, we probe the time-average decay rate of the propagator under long-time bulk dynamics as a signature of the Floquet emergent non-Hermitian skin effect. Our results provide a feasible and controllable way to realize universal one-way transport that is easily accessible to experiments. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.10000v2-abstract-full').style.display = 'none'; document.getElementById('2306.10000v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 9 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 16 June, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">14 pages, 14 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 109, 184302 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2306.03143">arXiv:2306.03143</a> <span> [<a href="https://arxiv.org/pdf/2306.03143">pdf</a>, <a href="https://arxiv.org/format/2306.03143">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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="Disordered Systems and Neural Networks">cond-mat.dis-nn</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="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/s42005-024-01542-8">10.1038/s42005-024-01542-8 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Machine learning reveals features of spinon Fermi surface </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kevin Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Feng%2C+S">Shi Feng</a>, <a href="/search/quant-ph?searchtype=author&query=Lensky%2C+Y+D">Yuri D. Lensky</a>, <a href="/search/quant-ph?searchtype=author&query=Trivedi%2C+N">Nandini Trivedi</a>, <a href="/search/quant-ph?searchtype=author&query=Kim%2C+E">Eun-Ah Kim</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2306.03143v2-abstract-short" style="display: inline;"> With rapid progress in simulation of strongly interacting quantum Hamiltonians, the challenge in characterizing unknown phases becomes a bottleneck for scientific progress. We demonstrate that a Quantum-Classical hybrid approach (QuCl) of mining sampled projective snapshots with interpretable classical machine learning can unveil signatures of seemingly featureless quantum states. The Kitaev-Heise… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.03143v2-abstract-full').style.display = 'inline'; document.getElementById('2306.03143v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2306.03143v2-abstract-full" style="display: none;"> With rapid progress in simulation of strongly interacting quantum Hamiltonians, the challenge in characterizing unknown phases becomes a bottleneck for scientific progress. We demonstrate that a Quantum-Classical hybrid approach (QuCl) of mining sampled projective snapshots with interpretable classical machine learning can unveil signatures of seemingly featureless quantum states. The Kitaev-Heisenberg model on a honeycomb lattice under external magnetic field presents an ideal system to test QuCl, where simulations have found an intermediate gapless phase (IGP) sandwiched between known phases, launching a debate over its elusive nature. We use the correlator convolutional neural network, trained on labeled projective snapshots, in conjunction with regularization path analysis to identify signatures of phases. We show that QuCl reproduces known features of established phases. Significantly, we also identify a signature of the IGP in the spin channel perpendicular to the field direction, which we interpret as a signature of Friedel oscillations of gapless spinons forming a Fermi surface. Our predictions can guide future experimental searches for spin liquids. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.03143v2-abstract-full').style.display = 'none'; document.getElementById('2306.03143v2-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 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 5 June, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">9 pages + 7 pages supplemental</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Commun. Phys. 7, 54 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2305.15972">arXiv:2305.15972</a> <span> [<a href="https://arxiv.org/pdf/2305.15972">pdf</a>, <a href="https://arxiv.org/format/2305.15972">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Logical Magic State Preparation with Fidelity Beyond the Distillation Threshold on a Superconducting Quantum Processor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Ye%2C+Y">Yangsen Ye</a>, <a href="/search/quant-ph?searchtype=author&query=He%2C+T">Tan He</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+H">He-Liang Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Wei%2C+Z">Zuolin Wei</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Y">Yiming Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+Y">Youwei Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+D">Dachao Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+Q">Qingling Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Guan%2C+H">Huijie Guan</a>, <a href="/search/quant-ph?searchtype=author&query=Cao%2C+S">Sirui Cao</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+F">Fusheng Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chung%2C+T">Tung-Hsun Chung</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+H">Hui Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Fan%2C+D">Daojin Fan</a>, <a href="/search/quant-ph?searchtype=author&query=Gong%2C+M">Ming Gong</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+C">Cheng Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+S">Shaojun Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Han%2C+L">Lianchen Han</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+N">Na Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shaowei Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yuan Li</a>, <a href="/search/quant-ph?searchtype=author&query=Liang%2C+F">Futian Liang</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+J">Jin Lin</a>, <a href="/search/quant-ph?searchtype=author&query=Qian%2C+H">Haoran Qian</a>, <a href="/search/quant-ph?searchtype=author&query=Rong%2C+H">Hao Rong</a> , et al. (13 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2305.15972v2-abstract-short" style="display: inline;"> Fault-tolerant quantum computing based on surface code has emerged as an attractive candidate for practical large-scale quantum computers to achieve robust noise resistance. To achieve universality, magic states preparation is a commonly approach for introducing non-Clifford gates. Here, we present a hardware-efficient and scalable protocol for arbitrary logical state preparation for the rotated s… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.15972v2-abstract-full').style.display = 'inline'; document.getElementById('2305.15972v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2305.15972v2-abstract-full" style="display: none;"> Fault-tolerant quantum computing based on surface code has emerged as an attractive candidate for practical large-scale quantum computers to achieve robust noise resistance. To achieve universality, magic states preparation is a commonly approach for introducing non-Clifford gates. Here, we present a hardware-efficient and scalable protocol for arbitrary logical state preparation for the rotated surface code, and further experimentally implement it on the \textit{Zuchongzhi} 2.1 superconducting quantum processor. An average of \hhl{$0.8983 \pm 0.0002$} logical fidelity at different logical states with distance-three is achieved, \hhl{taking into account both state preparation and measurement errors.} In particular, \hhl{the magic states $|A^{蟺/4}\rangle_L$, $|H\rangle_L$, and $|T\rangle_L$ are prepared non-destructively with logical fidelities of $0.8771 \pm 0.0009 $, $0.9090 \pm 0.0009 $, and $0.8890 \pm 0.0010$, respectively, which are higher than the state distillation protocol threshold, 0.859 (for H-type magic state) and 0.827 (for T -type magic state).} Our work provides a viable and efficient avenue for generating high-fidelity raw logical magic states, which is essential for realizing non-Clifford logical gates in the surface code. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.15972v2-abstract-full').style.display = 'none'; document.getElementById('2305.15972v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 May, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 25 May, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">In this version, we do not employ readout error mitigation strategies (in the previous version, we use readout transition matrix to mitigate the measurement error) to remove measurement errors because we believe it provides a more predictive assessment of the actual fidelity when generating and consuming magic states for a non-Clifford gate, as consuming the state involves measurement</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2305.11227">arXiv:2305.11227</a> <span> [<a href="https://arxiv.org/pdf/2305.11227">pdf</a>, <a href="https://arxiv.org/format/2305.11227">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 Gases">cond-mat.quant-gas</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div 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/PhysRevB.108.165132">10.1103/PhysRevB.108.165132 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Point-Gap Bound States in Non-Hermitian Systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Fang%2C+Z">Zixi Fang</a>, <a href="/search/quant-ph?searchtype=author&query=Fang%2C+C">Chen Fang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+K">Kai 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="2305.11227v2-abstract-short" style="display: inline;"> In this paper, we systematically investigate the impurity-induced bound states in 1D non-Hermitian systems. By establishing an exact relationship between impurity potential and bound-state energy, we determine the minimum impurity potential required to generate bound states within each point energy gap. We demonstrate that the absence of Bloch saddle points necessitates a finite threshold of impur… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.11227v2-abstract-full').style.display = 'inline'; document.getElementById('2305.11227v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2305.11227v2-abstract-full" style="display: none;"> In this paper, we systematically investigate the impurity-induced bound states in 1D non-Hermitian systems. By establishing an exact relationship between impurity potential and bound-state energy, we determine the minimum impurity potential required to generate bound states within each point energy gap. We demonstrate that the absence of Bloch saddle points necessitates a finite threshold of impurity potential; otherwise, infinitesimal impurity potential can create bound states. Furthermore, we show that the bound states residing in the point gaps with nonzero spectral winding exhibit sensitivity to boundary conditions and will be squeezed towards the edges when the boundaries are opened, indicating the bulk-boundary correspondence in terms of point-gap topology. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.11227v2-abstract-full').style.display = 'none'; document.getElementById('2305.11227v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 23 June, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 18 May, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">16 pages, 10 figures</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=Zhang%2C+K&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Zhang%2C+K&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=Zhang%2C+K&start=50" class="pagination-link " aria-label="Page 2" aria-current="page">2 </a> </li> <li> <a href="/search/?searchtype=author&query=Zhang%2C+K&start=100" class="pagination-link " aria-label="Page 3" aria-current="page">3 </a> </li> <li> <a href="/search/?searchtype=author&query=Zhang%2C+K&start=150" class="pagination-link " aria-label="Page 4" aria-current="page">4 </a> </li> </ul> </nav> <div class="is-hidden-tablet">  <span class="help" style="display: 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