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class="pagination-link " aria-label="Page 5" aria-current="page">5 </a> </li> <li><span class="pagination-ellipsis">…</span></li> </ul> </nav> <ol class="breathe-horizontal" start="1"> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.09470">arXiv:2411.09470</a> <span> [<a href="https://arxiv.org/pdf/2411.09470">pdf</a>, <a href="https://arxiv.org/format/2411.09470">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 synchronization in an all-optical stroboscopic quantum simulator </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yan Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xingli Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+W">Wenlin 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="2411.09470v1-abstract-short" style="display: inline;"> In this work, we propose an all-optical stroboscopic scheme to simulate an open quantum system. By incorporating the tritter, consisting of a group of beam splitters, we find the emergence of spontaneous anti-phase synchronization in the steady state. To better understand the synchronization and entanglement properties within the system, we utilize the relative error measure and find the distribut… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.09470v1-abstract-full').style.display = 'inline'; document.getElementById('2411.09470v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.09470v1-abstract-full" style="display: none;"> In this work, we propose an all-optical stroboscopic scheme to simulate an open quantum system. By incorporating the tritter, consisting of a group of beam splitters, we find the emergence of spontaneous anti-phase synchronization in the steady state. To better understand the synchronization and entanglement properties within the system, we utilize the relative error measure and find the distribution of logarithmic negativity in parameter space shows similar structures with the results of synchronization measure. Finally, we derive the adjoint master equation corresponding to the system when the synchronization condition is satisfied and explain the existence of oscillations. In addition, we explore the effect of non-Markovianity on synchronization, and we find that it only slows down the time for the system to reach the steady state but does not change the synchronization properties of the steady state. Our work provides a promising scheme for experimental studies focused on synchronization and other nonequilibrium steady states. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.09470v1-abstract-full').style.display = 'none'; document.getElementById('2411.09470v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 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">15 pages, 7 figures, accepted version</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.08502">arXiv:2411.08502</a> <span> [<a href="https://arxiv.org/pdf/2411.08502">pdf</a>, <a href="https://arxiv.org/format/2411.08502">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> A fiber array architecture for atom quantum computing </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xiao Li</a>, <a href="/search/quant-ph?searchtype=author&query=Hou%2C+J">Jia-Yi Hou</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+J">Jia-Chao Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+G">Guang-Wei Wang</a>, <a href="/search/quant-ph?searchtype=author&query=He%2C+X">Xiao-Dong He</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+F">Feng Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Y">Yi-Bo Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+M">Min Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+J">Jin Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+P">Peng Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhan%2C+M">Ming-Sheng Zhan</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="2411.08502v1-abstract-short" style="display: inline;"> Arrays of single atoms trapped in optical tweezers are increasingly recognized as a promising platform for scalable quantum computing. In both the fault-tolerant and NISQ eras, the ability to individually control qubits is essential for the efficient execution of quantum circuits. Time-division multiplexed control schemes based on atom shuttling or beam scanning have been employed to build program… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.08502v1-abstract-full').style.display = 'inline'; document.getElementById('2411.08502v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.08502v1-abstract-full" style="display: none;"> Arrays of single atoms trapped in optical tweezers are increasingly recognized as a promising platform for scalable quantum computing. In both the fault-tolerant and NISQ eras, the ability to individually control qubits is essential for the efficient execution of quantum circuits. Time-division multiplexed control schemes based on atom shuttling or beam scanning have been employed to build programmable neutral atom quantum processors, but achieving high-rate, highly parallel gate operations remains a challenge. Here, we propose a fiber array architecture for atom quantum computing capable of fully independent control of individual atoms. The trapping and addressing lasers for each individual atom are emitted from the same optical waveguide, enabling robust control through common-mode suppression of beam pointing noise. Using a fiber array, we experimentally demonstrate the trapping and independent control of ten single atoms in two-dimensional optical tweezers, achieving individually addressed single-qubit gate with an average fidelity of 0.9966(3). Moreover, we perform simultaneous arbitrary single-qubit gate on four randomly selected qubits, resulting in an average fidelity of 0.9961(4). Our work paves the way for time-efficient execution of quantum algorithms on neutral atom quantum computers. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.08502v1-abstract-full').style.display = 'none'; document.getElementById('2411.08502v1-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">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</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.03972">arXiv:2411.03972</a> <span> [<a href="https://arxiv.org/pdf/2411.03972">pdf</a>, <a href="https://arxiv.org/format/2411.03972">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="Numerical Analysis">math.NA</span> </div> </div> <p class="title is-5 mathjax"> Toward end-to-end quantum simulation for protein dynamics </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Liu%2C+Z">Zhenning Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xiantao Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+C">Chunhao Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+J">Jin-Peng Liu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2411.03972v1-abstract-short" style="display: inline;"> Modeling and simulating the protein folding process overall remains a grand challenge in computational biology. We systematically investigate end-to-end quantum algorithms for simulating various protein dynamics with effects, such as mechanical forces or stochastic noises. We offer efficient quantum simulation algorithms to produce quantum encoding of the final states, history states, or density m… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.03972v1-abstract-full').style.display = 'inline'; document.getElementById('2411.03972v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.03972v1-abstract-full" style="display: none;"> Modeling and simulating the protein folding process overall remains a grand challenge in computational biology. We systematically investigate end-to-end quantum algorithms for simulating various protein dynamics with effects, such as mechanical forces or stochastic noises. We offer efficient quantum simulation algorithms to produce quantum encoding of the final states, history states, or density matrices of inhomogeneous or stochastic harmonic oscillator models. For the read-in setting, we design (i) efficient quantum algorithms for initial state preparation, utilizing counter-based random number generator and rejection sampling, and (ii) depth-efficient approaches for molecular structure loading. Both are particularly important in handling large protein molecules. For the read-out setting, our algorithms estimate various classical observables, such as energy, low vibration modes, density of states, correlation of displacement, and optimal control of molecular dynamics. We also show classical numerical experiments focused on estimating the density of states and applying the optimal control to facilitate conformation changes to verify our arguments on potential quantum speedups. Overall, our study demonstrates that the quantum simulation of protein dynamics can be a solid end-to-end application in the era of early or fully fault-tolerant quantum computing. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.03972v1-abstract-full').style.display = 'none'; document.getElementById('2411.03972v1-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">61 pages, 10 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/2411.03640">arXiv:2411.03640</a> <span> [<a href="https://arxiv.org/pdf/2411.03640">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1126/sciadv.adl4871">10.1126/sciadv.adl4871 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Efficient learning of mixed-state tomography for photonic quantum walk </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Q">Qin-Qin Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Dong%2C+S">Shaojun Dong</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xiao-Wei Li</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+X">Xiao-Ye Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+C">Chao Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Han%2C+S">Shuai Han</a>, <a href="/search/quant-ph?searchtype=author&query=Yung%2C+M">Man-Hong Yung</a>, <a href="/search/quant-ph?searchtype=author&query=Han%2C+Y">Yong-Jian Han</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+C">Chuan-Feng Li</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+G">Guang-Can 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="2411.03640v1-abstract-short" style="display: inline;"> Noise-enhanced applications in open quantum walk (QW) have recently seen a surge due to their ability to improve performance. However, verifying the success of open QW is challenging, as mixed-state tomography is a resource-intensive process, and implementing all required measurements is almost impossible due to various physical constraints. To address this challenge, we present a neural-network-b… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.03640v1-abstract-full').style.display = 'inline'; document.getElementById('2411.03640v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.03640v1-abstract-full" style="display: none;"> Noise-enhanced applications in open quantum walk (QW) have recently seen a surge due to their ability to improve performance. However, verifying the success of open QW is challenging, as mixed-state tomography is a resource-intensive process, and implementing all required measurements is almost impossible due to various physical constraints. To address this challenge, we present a neural-network-based method for reconstructing mixed states with a high fidelity (~97.5%) while costing only 50% of the number of measurements typically required for open discrete-time QW in one dimension. Our method uses a neural density operator that models the system and environment, followed by a generalized natural gradient descent procedure that significantly speeds up the training process. Moreover, we introduce a compact interferometric measurement device, improving the scalability of our photonic QW setup that enables experimental learning of mixed states. Our results demonstrate that highly expressive neural networks can serve as powerful alternatives to traditional state tomography. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.03640v1-abstract-full').style.display = 'none'; document.getElementById('2411.03640v1-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 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">Journal ref:</span> Sci. Adv. 10, eadl4871 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.03599">arXiv:2411.03599</a> <span> [<a href="https://arxiv.org/pdf/2411.03599">pdf</a>, <a href="https://arxiv.org/format/2411.03599">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="Numerical Analysis">math.NA</span> </div> </div> <p class="title is-5 mathjax"> Structure-preserving quantum algorithms for linear and nonlinear Hamiltonian systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wu%2C+H">Hsuan-Cheng Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xiantao 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="2411.03599v1-abstract-short" style="display: inline;"> Hamiltonian systems of ordinary and partial differential equations are fundamental across modern science and engineering, appearing in models that span virtually all physical scales. A critical property for the robustness and stability of computational methods in such systems is the symplectic structure, which preserves geometric properties like phase-space volume over time and energy conservation… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.03599v1-abstract-full').style.display = 'inline'; document.getElementById('2411.03599v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.03599v1-abstract-full" style="display: none;"> Hamiltonian systems of ordinary and partial differential equations are fundamental across modern science and engineering, appearing in models that span virtually all physical scales. A critical property for the robustness and stability of computational methods in such systems is the symplectic structure, which preserves geometric properties like phase-space volume over time and energy conservation over an extended period. In this paper, we present quantum algorithms that incorporate symplectic integrators, ensuring the preservation of this key structure. We demonstrate how these algorithms maintain the symplectic properties for both linear and nonlinear Hamiltonian systems. Additionally, we provide a comprehensive theoretical analysis of the computational complexity, showing that our approach offers both accuracy and improved efficiency over classical algorithms. These results highlight the potential application of quantum algorithms for solving large-scale Hamiltonian systems while preserving essential physical properties. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.03599v1-abstract-full').style.display = 'none'; document.getElementById('2411.03599v1-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 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/2410.23560">arXiv:2410.23560</a> <span> [<a href="https://arxiv.org/pdf/2410.23560">pdf</a>, <a href="https://arxiv.org/format/2410.23560">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"> Untrained Filtering with Trained Focusing for Superior Quantum Architecture Search </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Yu%2C+L">Lian-Hui Yu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xiao-Yu Li</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+G">Geng Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+Q">Qin-Sheng Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+H">Hui Li</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+G">Guo-Wu 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="2410.23560v2-abstract-short" style="display: inline;"> Quantum architecture search (QAS) represents a fundamental challenge in quantum machine learning. Unlike previous methods that treat it as a static search process, from a perspective on QAS as an item retrieval task in vast search space, we decompose the search process into dynamic alternating phases of coarse and fine-grained knowledge learning. We propose quantum untrained-explored synergistic t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.23560v2-abstract-full').style.display = 'inline'; document.getElementById('2410.23560v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.23560v2-abstract-full" style="display: none;"> Quantum architecture search (QAS) represents a fundamental challenge in quantum machine learning. Unlike previous methods that treat it as a static search process, from a perspective on QAS as an item retrieval task in vast search space, we decompose the search process into dynamic alternating phases of coarse and fine-grained knowledge learning. We propose quantum untrained-explored synergistic trained architecture (QUEST-A),a framework through coarse-grained untrained filtering for rapid search space reduction and fine-grained trained focusing for precise space refinement in progressive QAS. QUEST-A develops an evolutionary mechanism with knowledge accumulation and reuse to enhance multi-level knowledge transfer in architecture searching. Experiments demonstrate QUEST-A's superiority over existing methods: enhancing model expressivity in signal representation, maintaining high performance across varying complexities in image classification, and achieving order-of-magnitude precision improvements in variational quantum eigensolver tasks, providing a transferable methodology for QAS. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.23560v2-abstract-full').style.display = 'none'; document.getElementById('2410.23560v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 30 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.21413">arXiv:2410.21413</a> <span> [<a href="https://arxiv.org/pdf/2410.21413">pdf</a>, <a href="https://arxiv.org/format/2410.21413">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="Emerging Technologies">cs.ET</span> </div> </div> <p class="title is-5 mathjax"> Approaches to Simultaneously Solving Variational Quantum Eigensolver Problems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Hutchings%2C+A">Adam Hutchings</a>, <a href="/search/quant-ph?searchtype=author&query=Yarnot%2C+E">Eric Yarnot</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xinpeng Li</a>, <a href="/search/quant-ph?searchtype=author&query=Guan%2C+Q">Qiang Guan</a>, <a href="/search/quant-ph?searchtype=author&query=Xie%2C+N">Ning Xie</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+S">Shuai Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Chaudhary%2C+V">Vipin Chaudhary</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="2410.21413v1-abstract-short" style="display: inline;"> The variational quantum eigensolver (VQE), a type of variational quantum algorithm, is a hybrid quantum-classical algorithm to find the lowest-energy eigenstate of a particular Hamiltonian. We investigate ways to optimize the VQE solving process on multiple instances of the same problem, by observing the process on one instance of the problem to inform initialization for other processes. We aim to… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.21413v1-abstract-full').style.display = 'inline'; document.getElementById('2410.21413v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.21413v1-abstract-full" style="display: none;"> The variational quantum eigensolver (VQE), a type of variational quantum algorithm, is a hybrid quantum-classical algorithm to find the lowest-energy eigenstate of a particular Hamiltonian. We investigate ways to optimize the VQE solving process on multiple instances of the same problem, by observing the process on one instance of the problem to inform initialization for other processes. We aim to take advantage of the VQE solution process to obtain useful information while disregarding information which we can predict to not be very useful. In particular, we find that the solution process produces lots of data with very little new information. Therefore, we can safely disregard much of this repetitive information with little effect on the outcome of the solution process. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.21413v1-abstract-full').style.display = 'none'; document.getElementById('2410.21413v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 28 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">4 pages, 5 figures, QCCC-24 conference</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.20313">arXiv:2410.20313</a> <span> [<a href="https://arxiv.org/pdf/2410.20313">pdf</a>, <a href="https://arxiv.org/format/2410.20313">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Distributed, Parallel, and Cluster Computing">cs.DC</span> </div> </div> <p class="title is-5 mathjax"> Efficient Circuit Wire Cutting Based on Commuting Groups </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xinpeng Li</a>, <a href="/search/quant-ph?searchtype=author&query=Kulkarni%2C+V">Vinooth Kulkarni</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+D+T">Daniel T. Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Guan%2C+Q">Qiang Guan</a>, <a href="/search/quant-ph?searchtype=author&query=Jiang%2C+W">Weiwen Jiang</a>, <a href="/search/quant-ph?searchtype=author&query=Xie%2C+N">Ning Xie</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+S">Shuai Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Chaudhary%2C+V">Vipin Chaudhary</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="2410.20313v1-abstract-short" style="display: inline;"> Current quantum devices face challenges when dealing with large circuits due to error rates as circuit size and the number of qubits increase. The circuit wire-cutting technique addresses this issue by breaking down a large circuit into smaller, more manageable subcircuits. However, the exponential increase in the number of subcircuits and the complexity of reconstruction as more cuts are made pos… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.20313v1-abstract-full').style.display = 'inline'; document.getElementById('2410.20313v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.20313v1-abstract-full" style="display: none;"> Current quantum devices face challenges when dealing with large circuits due to error rates as circuit size and the number of qubits increase. The circuit wire-cutting technique addresses this issue by breaking down a large circuit into smaller, more manageable subcircuits. However, the exponential increase in the number of subcircuits and the complexity of reconstruction as more cuts are made poses a great practical challenge. Inspired by ancilla-assisted quantum process tomography and the MUBs-based grouping technique for simultaneous measurement, we propose a new approach that can reduce subcircuit running overhead. The approach first uses ancillary qubits to transform all quantum input initializations into quantum output measurements. These output measurements are then organized into commuting groups for the purpose of simultaneous measurement, based on MUBs-based grouping. This approach significantly reduces the number of necessary subcircuits as well as the total number of shots. Lastly, we provide numerical experiments to demonstrate the complexity reduction. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.20313v1-abstract-full').style.display = 'none'; document.getElementById('2410.20313v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 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">Accepted in IEEE International Conference on Quantum Computing and Engineering - QCE24</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.17277">arXiv:2410.17277</a> <span> [<a href="https://arxiv.org/pdf/2410.17277">pdf</a>, <a href="https://arxiv.org/format/2410.17277">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="Neural and Evolutionary Computing">cs.NE</span> </div> </div> <p class="title is-5 mathjax"> A practical applicable quantum-classical hybrid ant colony algorithm for the NISQ era </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Qiu%2C+Q">Qian Qiu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+L">Liang Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+M">Mohan Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Sun%2C+Q">Qichun Sun</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xiaogang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+D">Da-Chuang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+H">Hua Xu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2410.17277v1-abstract-short" style="display: inline;"> Quantum ant colony optimization (QACO) has drew much attention since it combines the advantages of quantum computing and ant colony optimization (ACO) algorithm overcoming some limitations of the traditional ACO algorithm. However,due to the hardware resource limitations of currently available quantum computers, the practical application of the QACO is still not realized. In this paper, we develop… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.17277v1-abstract-full').style.display = 'inline'; document.getElementById('2410.17277v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.17277v1-abstract-full" style="display: none;"> Quantum ant colony optimization (QACO) has drew much attention since it combines the advantages of quantum computing and ant colony optimization (ACO) algorithm overcoming some limitations of the traditional ACO algorithm. However,due to the hardware resource limitations of currently available quantum computers, the practical application of the QACO is still not realized. In this paper, we developed a quantum-classical hybrid algorithm by combining the clustering algorithm with QACO algorithm.This extended QACO can handle large-scale optimization problems with currently available quantum computing resource. We have tested the effectiveness and performance of the extended QACO algorithm with the Travelling Salesman Problem (TSP) as benchmarks, and found the algorithm achieves better performance under multiple diverse datasets. In addition, we investigated the noise impact on the extended QACO and evaluated its operation possibility on current available noisy intermediate scale quantum(NISQ) devices. Our work shows that the combination of the clustering algorithm with QACO effectively improved its problem solving scale, which makes its practical application possible in current NISQ era of quantum computing. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.17277v1-abstract-full').style.display = 'none'; document.getElementById('2410.17277v1-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 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">arXiv admin note: substantial text overlap with arXiv:2403.00367</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.15870">arXiv:2410.15870</a> <span> [<a href="https://arxiv.org/pdf/2410.15870">pdf</a>, <a href="https://arxiv.org/ps/2410.15870">ps</a>, <a href="https://arxiv.org/format/2410.15870">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> A new general quantum state verification protocol by the classical shadow method </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xiaodi 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="2410.15870v2-abstract-short" style="display: inline;"> The task of verifying if a quantum device produces a specific state is ubiquitous in many applications of modern quantum technologies. In the conventional framework of quantum state verification, we need to design an optimal or efficient protocol for each type of state elaborately. In a recent paper arXiv:2404.07281v1, Hsin-Yuan Huang et al. propose a new distinct protocol utilizing the classical… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.15870v2-abstract-full').style.display = 'inline'; document.getElementById('2410.15870v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.15870v2-abstract-full" style="display: none;"> The task of verifying if a quantum device produces a specific state is ubiquitous in many applications of modern quantum technologies. In the conventional framework of quantum state verification, we need to design an optimal or efficient protocol for each type of state elaborately. In a recent paper arXiv:2404.07281v1, Hsin-Yuan Huang et al. propose a new distinct protocol utilizing the classical shadow, called the shadow overlap protocol, which has the potential for efficiently verifying many types of state in one time. In this paper, we reformulate this new protocol by the terminologies of hypothesis testing, on which the conventional framework is also based, to explore the similarities and differences between them. Then, we propose a new protocol which combines the ideas of the conventional framework and the shadow overlap protocol. Our protocol strengthens the ability of the shadow overlap protocol and overcomes some shortages of the latter, like having a better sample complexity and dealing with the states with special structures more naturally. Finally, we apply our new protocol to the GHZ state and the stabilizer state to illustrate its capacities. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.15870v2-abstract-full').style.display = 'none'; document.getElementById('2410.15870v2-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 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 21 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">14 pages. v2: references added</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.14850">arXiv:2410.14850</a> <span> [<a href="https://arxiv.org/pdf/2410.14850">pdf</a>, <a href="https://arxiv.org/format/2410.14850">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Other Condensed Matter">cond-mat.other</span> </div> </div> <p class="title is-5 mathjax"> Cooperative non-reciprocal emission and quantum sensing of symmetry breaking </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xin Li</a>, <a href="/search/quant-ph?searchtype=author&query=Flebus%2C+B">Benedetta Flebus</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="2410.14850v2-abstract-short" style="display: inline;"> Non-reciprocal propagation of energy and information is fundamental to a wide range of quantum technology applications. In this work, we explore the quantum many-body dynamics of a qubit ensemble coupled to a shared bath that mediates coherent and dissipative inter-qubit interactions with both symmetric and anti-symmetric components. We find that the interplay between anti-symmetric (symmetric) co… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.14850v2-abstract-full').style.display = 'inline'; document.getElementById('2410.14850v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.14850v2-abstract-full" style="display: none;"> Non-reciprocal propagation of energy and information is fundamental to a wide range of quantum technology applications. In this work, we explore the quantum many-body dynamics of a qubit ensemble coupled to a shared bath that mediates coherent and dissipative inter-qubit interactions with both symmetric and anti-symmetric components. We find that the interplay between anti-symmetric (symmetric) coherent and symmetric (anti-symmetric) dissipative interactions results in non-reciprocal couplings, which, in turn, generate a spatially asymmetric emission pattern. We demonstrate that this pattern arises from non-reciprocal interactions coupling different quantum many-body states within a specific excitation manifold. Focusing on solid-state baths, we show that their lack of time-reversal and inversion symmetry is a key ingredient for generating non-reciprocal dynamics in the qubit ensemble. With the plethora of quantum materials that exhibit this symmetry breaking at equilibrium, our approach paves the way for realizing cooperative non-reciprocal transport in qubit ensembles without requiring time-modulated external drives or complex engineering. Using an ensemble of nitrogen-vacancy (NV) centers coupled to a generic non-centrosymmetric ferromagnetic bath as a concrete example, we demonstrate that our predictions can be tested in near-future experiments. As the spatial asymmetry in the relaxation dynamics of the qubit ensemble is a direct probe of symmetry breaking in the solid-state bath, our work also opens the door to developing model-agnostic quantum sensing schemes capable of detecting bath properties invisible to current state-of-the-art protocols, which operate solid-state defects as single-qubit sensors. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.14850v2-abstract-full').style.display = 'none'; document.getElementById('2410.14850v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 18 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.04003">arXiv:2410.04003</a> <span> [<a href="https://arxiv.org/pdf/2410.04003">pdf</a>, <a href="https://arxiv.org/ps/2410.04003">ps</a>, <a href="https://arxiv.org/format/2410.04003">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"> Device-independent quantum secret sharing with advanced random key generation basis </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Q">Qi Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Ying%2C+J">Jia-Wei Ying</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zhong-Jian Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhong%2C+W">Wei Zhong</a>, <a href="/search/quant-ph?searchtype=author&query=Du%2C+M">Ming-Ming Du</a>, <a href="/search/quant-ph?searchtype=author&query=Shen%2C+S">Shu-Ting Shen</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xi-Yun Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+A">An-Lei Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Gu%2C+S">Shi-Pu Gu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+X">Xing-Fu Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+L">Lan Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Sheng%2C+Y">Yu-Bo Sheng</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="2410.04003v1-abstract-short" style="display: inline;"> Quantum secret sharing (QSS) enables a dealer to securely distribute keys to multiple players. Device-independent (DI) QSS can resist all possible attacks from practical imperfect devices and provide QSS the highest level of security in theory. However, DI QSS requires high-performance devices, especially for low-noise channels, which is a big challenge for its experimental demonstration. We propo… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.04003v1-abstract-full').style.display = 'inline'; document.getElementById('2410.04003v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.04003v1-abstract-full" style="display: none;"> Quantum secret sharing (QSS) enables a dealer to securely distribute keys to multiple players. Device-independent (DI) QSS can resist all possible attacks from practical imperfect devices and provide QSS the highest level of security in theory. However, DI QSS requires high-performance devices, especially for low-noise channels, which is a big challenge for its experimental demonstration. We propose a DI QSS protocol with the advanced random key generation basis strategy, which combines the random key generation basis with the noise preprocessing and postselection strategies. We develop the methods to simplify Eve's conditional entropy bound and numerically simulate the key generation rate in an acceptable time. Our DI QSS protocol has some advantages. First, it can increase the noise tolerance threshold from initial 7.147% to 9.231% (29.16% growth), and reduce the global detection efficiency threshold from 96.32% to 93.41%. The maximal distance between any two users increases to 1.43 km, which is about 5.5 times of the initial value. Second, by randomly selecting two basis combinations to generate the key, our DI QSS protocol can reduce the entanglement resource consumption. Our protocol has potential for DI QSS's experimental demonstration and application in the future. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.04003v1-abstract-full').style.display = 'none'; document.getElementById('2410.04003v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">16 pages, 6 figures, 1 table</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.02547">arXiv:2410.02547</a> <span> [<a href="https://arxiv.org/pdf/2410.02547">pdf</a>, <a href="https://arxiv.org/format/2410.02547">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Artificial Intelligence">cs.AI</span> </div> </div> <p class="title is-5 mathjax"> Personalized Quantum Federated Learning for Privacy Image Classification </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Shi%2C+J">Jinjing Shi</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+T">Tian Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+S">Shichao Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xuelong 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="2410.02547v1-abstract-short" style="display: inline;"> Quantum federated learning has brought about the improvement of privacy image classification, while the lack of personality of the client model may contribute to the suboptimal of quantum federated learning. A personalized quantum federated learning algorithm for privacy image classification is proposed to enhance the personality of the client model in the case of an imbalanced distribution of ima… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.02547v1-abstract-full').style.display = 'inline'; document.getElementById('2410.02547v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.02547v1-abstract-full" style="display: none;"> Quantum federated learning has brought about the improvement of privacy image classification, while the lack of personality of the client model may contribute to the suboptimal of quantum federated learning. A personalized quantum federated learning algorithm for privacy image classification is proposed to enhance the personality of the client model in the case of an imbalanced distribution of images. First, a personalized quantum federated learning model is constructed, in which a personalized layer is set for the client model to maintain the personalized parameters. Second, a personalized quantum federated learning algorithm is introduced to secure the information exchanged between the client and server.Third, the personalized federated learning is applied to image classification on the FashionMNIST dataset, and the experimental results indicate that the personalized quantum federated learning algorithm can obtain global and local models with excellent performance, even in situations where local training samples are imbalanced. The server's accuracy is 100% with 8 clients and a distribution parameter of 100, outperforming the non-personalized model by 7%. The average client accuracy is 2.9% higher than that of the non-personalized model with 2 clients and a distribution parameter of 1. Compared to previous quantum federated learning algorithms, the proposed personalized quantum federated learning algorithm eliminates the need for additional local training while safeguarding both model and data privacy.It may facilitate broader adoption and application of quantum technologies, and pave the way for more secure, scalable, and efficient quantum distribute machine learning solutions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.02547v1-abstract-full').style.display = 'none'; document.getElementById('2410.02547v1-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 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.00803">arXiv:2410.00803</a> <span> [<a href="https://arxiv.org/pdf/2410.00803">pdf</a>, <a href="https://arxiv.org/format/2410.00803">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Gases">cond-mat.quant-gas</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Atomic Physics">physics.atom-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Squeezing atomic $p$-orbital condensates for detecting gravitational waves </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Yu%2C+X">Xinyang Yu</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+W+V">W. Vincent Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xiaopeng 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="2410.00803v2-abstract-short" style="display: inline;"> Precision gravitational wave measurement transforms research beyond general relativity and cosmology. Advances are made by applying quantum enhanced interferometry into the LIGO, Virgo and KAGRA detectors. Here, we develop an atomic sensor that employs a $p$-orbital Bose-Einstein condensate in an optical lattice to project gravitational wave signals into an orbital squeezed state. This entangled s… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.00803v2-abstract-full').style.display = 'inline'; document.getElementById('2410.00803v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.00803v2-abstract-full" style="display: none;"> Precision gravitational wave measurement transforms research beyond general relativity and cosmology. Advances are made by applying quantum enhanced interferometry into the LIGO, Virgo and KAGRA detectors. Here, we develop an atomic sensor that employs a $p$-orbital Bose-Einstein condensate in an optical lattice to project gravitational wave signals into an orbital squeezed state. This entangled state couples linearly to the spacetime distortion signals received via a Michelson interferometer. Simulation data show that this sensor improves sensitivity over LIGO's quantum noise by approximately one order of magnitude and detection volume by $\sim 10^3$ in key frequency regimes. Additionally, it reduces the required laser power by five orders of magnitude. These results suggest that atomic orbital squeezing offers a compelling alternative to conventional techniques, offering a qualitatively different avenue for gravitational wave-based detection of dark matter, black holes, and the equation of state in neutron stars. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.00803v2-abstract-full').style.display = 'none'; document.getElementById('2410.00803v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 1 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">7+55 pages, 4+15 figures, 1 table</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2409.17930">arXiv:2409.17930</a> <span> [<a href="https://arxiv.org/pdf/2409.17930">pdf</a>, <a href="https://arxiv.org/format/2409.17930">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"> Codesigned counterdiabatic quantum optimization on a photonic quantum processor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Shang%2C+X">Xiao-Wen Shang</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+X">Xuan Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Hegade%2C+N+N">Narendra N. Hegade</a>, <a href="/search/quant-ph?searchtype=author&query=Lan%2C+Z">Ze-Feng Lan</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xuan-Kun Li</a>, <a href="/search/quant-ph?searchtype=author&query=Tang%2C+H">Hao Tang</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+Y">Yu-Quan Peng</a>, <a href="/search/quant-ph?searchtype=author&query=Solano%2C+E">Enrique Solano</a>, <a href="/search/quant-ph?searchtype=author&query=Jin%2C+X">Xian-Min Jin</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2409.17930v1-abstract-short" style="display: inline;"> Codesign, an integral part of computer architecture referring to the information interaction in hardware-software stack, is able to boost the algorithm mapping and execution in the computer hardware. This well applies to the noisy intermediate-scale quantum era, where quantum algorithms and quantum processors both need to be shaped to allow for advantages in experimental implementations. The state… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.17930v1-abstract-full').style.display = 'inline'; document.getElementById('2409.17930v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.17930v1-abstract-full" style="display: none;"> Codesign, an integral part of computer architecture referring to the information interaction in hardware-software stack, is able to boost the algorithm mapping and execution in the computer hardware. This well applies to the noisy intermediate-scale quantum era, where quantum algorithms and quantum processors both need to be shaped to allow for advantages in experimental implementations. The state-of-the-art quantum adiabatic optimization algorithm faces challenges for scaling up, where the deteriorating optimization performance is not necessarily alleviated by increasing the circuit depth given the noise in the hardware. The counterdiabatic term can be introduced to accelerate the convergence, but decomposing the unitary operator corresponding to the counterdiabatic terms into one and two-qubit gates may add additional burden to the digital circuit depth. In this work, we focus on the counterdiabatic protocol with a codesigned approach to implement this algorithm on a photonic quantum processor. The tunable Mach-Zehnder interferometer mesh provides rich programmable parameters for local and global manipulation, making it able to perform arbitrary unitary evolutions. Accordingly, we directly implement the unitary operation associated to the counterdiabatic quantum optimization on our processor without prior digitization. Furthermore, we develop and implement an optimized counterdiabatic method by tackling the higher-order many-body interaction terms. Moreover, we benchmark the performance in the case of factorization, by comparing the final success probability and the convergence speed. In conclusion, we experimentally demonstrate the advantages of a codesigned mapping of counterdiabatic quantum dynamics for quantum computing on photonic platforms. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.17930v1-abstract-full').style.display = 'none'; document.getElementById('2409.17930v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 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">9 pages, 4 figures. 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/2409.14856">arXiv:2409.14856</a> <span> [<a href="https://arxiv.org/pdf/2409.14856">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> </div> <p class="title is-5 mathjax"> Coherent population trapping and spin relaxation of a silicon vacancy center in diamond at mK temperatures </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wu%2C+S">Shuhao Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xinzhu Li</a>, <a href="/search/quant-ph?searchtype=author&query=Gallagher%2C+I">Ian Gallagher</a>, <a href="/search/quant-ph?searchtype=author&query=Lawrie%2C+B">Benjamin Lawrie</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+H">Hailin 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="2409.14856v1-abstract-short" style="display: inline;"> We report experimental studies of coherent population trapping and spin relaxation in a temperature range between 4 K and 100 mK in a silicon vacancy (SiV) center subject to a transverse magnetic field. Near and below 1 K, phonon-induced spin dephasing becomes negligible compared with that induced by the spin bath of naturally abundant 13C atoms. The temperature dependence of the spin dephasing ra… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.14856v1-abstract-full').style.display = 'inline'; document.getElementById('2409.14856v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.14856v1-abstract-full" style="display: none;"> We report experimental studies of coherent population trapping and spin relaxation in a temperature range between 4 K and 100 mK in a silicon vacancy (SiV) center subject to a transverse magnetic field. Near and below 1 K, phonon-induced spin dephasing becomes negligible compared with that induced by the spin bath of naturally abundant 13C atoms. The temperature dependence of the spin dephasing rates agrees with the theoretical expectation that phonon-induced spin dephasing arises primarily from orbital relaxation induced by first order electron-phonon interactions. A nearly 100-fold increase in spin lifetime is observed when the temperature is lowered from 4 K to slightly below 1 K, indicating that two-phonon spin-flip transitions play an essential role in the spin relaxation of SiV ground states. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.14856v1-abstract-full').style.display = 'none'; document.getElementById('2409.14856v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 23 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2409.14310">arXiv:2409.14310</a> <span> [<a href="https://arxiv.org/pdf/2409.14310">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"> Full characterization of an all fiber source of heralded single photons </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Y">Yunxiao Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Cui%2C+L">Liang Cui</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+X">Xueshi Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+W">Wen Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xiaoying Li</a>, <a href="/search/quant-ph?searchtype=author&query=Ou%2C+Z+Y">Z. Y. Ou</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="2409.14310v1-abstract-short" style="display: inline;"> We demonstrate a heralded single photon source which is based on the photon pairs generated from pulse pumped spontaneous four wave mixing in a piece of commercially available dispersion shifted fiber. The single photon source at 1550 nm telecom band is characterized with both photon counting technique and homodyne detection method. The heralding efficiency and mode purity can be measured by photo… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.14310v1-abstract-full').style.display = 'inline'; document.getElementById('2409.14310v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.14310v1-abstract-full" style="display: none;"> We demonstrate a heralded single photon source which is based on the photon pairs generated from pulse pumped spontaneous four wave mixing in a piece of commercially available dispersion shifted fiber. The single photon source at 1550 nm telecom band is characterized with both photon counting technique and homodyne detection method. The heralding efficiency and mode purity can be measured by photon counting while the vacuum contribution part can be found by homodyne detection. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.14310v1-abstract-full').style.display = 'none'; document.getElementById('2409.14310v1-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 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2409.13510">arXiv:2409.13510</a> <span> [<a href="https://arxiv.org/pdf/2409.13510">pdf</a>, <a href="https://arxiv.org/format/2409.13510">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"> Simulating the Schwinger Model with a Regularized Variational Quantum Imaginary Time Evolution </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xiao-Wei Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+F">Fei Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhuang%2C+J">Jiapei Zhuang</a>, <a href="/search/quant-ph?searchtype=author&query=Yung%2C+M">Man-Hong Yung</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="2409.13510v1-abstract-short" style="display: inline;"> The Schwinger model serves as a benchmark for testing non-perturbative algorithms in quantum chromodynamics (QCD), emphasizing its similarities to QCD in strong coupling regimes, primarily due to the phenomena such as confinement and charge screening. However, classical algorithms encounter challenges when simulating the Schwinger model, such as the "sign problem" and the difficulty in handling la… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.13510v1-abstract-full').style.display = 'inline'; document.getElementById('2409.13510v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.13510v1-abstract-full" style="display: none;"> The Schwinger model serves as a benchmark for testing non-perturbative algorithms in quantum chromodynamics (QCD), emphasizing its similarities to QCD in strong coupling regimes, primarily due to the phenomena such as confinement and charge screening. However, classical algorithms encounter challenges when simulating the Schwinger model, such as the "sign problem" and the difficulty in handling large-scale systems. These limitations motivate the exploration of alternative simulation approaches, including quantum computing techniques, to overcome the obstacles. While existing variational quantum algorithms (VQAs) methods for simulating the Schwinger model primarily rely on mathematical gradient-based optimization, which sometimes fail to provide intuitive and physically-guided optimization pathways. In contrast, the Variational Quantum Imaginary Time Evolution (VQITE) method offers a physically-inspired optimization approach. Therefore, we introduce that VQITE holds promise as a potent tool for simulating the Schwinger model. However, the standard VQITE method is not sufficiently stable, as it encounters difficulties with the non-invertible matrix problem. To address this issue, we have proposed a regularized version of the VQITE, which we have named the Regularized-VQITE (rVQITE) method, as it incorporates a truncation-based approach. Through numerical simulations, we demonstrate that our proposed rVQITE approach achieves better performance and exhibits faster convergence compared to other related techniques. We employ the rVQITE method to simulate the phase diagrams of various physical observables in the Schwinger model, and the resulting phase boundaries are in agreement with those obtained from an exact computational approach. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.13510v1-abstract-full').style.display = 'none'; document.getElementById('2409.13510v1-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> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2409.05419">arXiv:2409.05419</a> <span> [<a href="https://arxiv.org/pdf/2409.05419">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> </div> </div> <p class="title is-5 mathjax"> Super-bunching light with giant high-order correlations and extreme multi-photon events </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Qin%2C+C">Chengbing Qin</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yuanyuan Li</a>, <a href="/search/quant-ph?searchtype=author&query=Yan%2C+Y">Yu Yan</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+J">Jiamin Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xiangdong Li</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+Y">Yunrui Song</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+X">Xuedong Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Han%2C+S">Shuangping Han</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+Z">Zihua Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Y">Yanqiang Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+G">Guofeng Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+R">Ruiyun Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Hu%2C+J">Jianyong Hu</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+Z">Zhichun Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+X">Xinhui Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Xiao%2C+L">Liantuan Xiao</a>, <a href="/search/quant-ph?searchtype=author&query=Jia%2C+S">Suotang Jia</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2409.05419v3-abstract-short" style="display: inline;"> Non-classical light sources emitting bundles of N-photons with strong correlation represent versatile resources of interdisciplinary importance with applications ranging from fundamental tests of quantum mechanics to quantum information processing. Yet, high-order correlations, gN(0),quantifying photon correlation, are still limited to hundreds. Here, we report the generation of a super-bunching l… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.05419v3-abstract-full').style.display = 'inline'; document.getElementById('2409.05419v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.05419v3-abstract-full" style="display: none;"> Non-classical light sources emitting bundles of N-photons with strong correlation represent versatile resources of interdisciplinary importance with applications ranging from fundamental tests of quantum mechanics to quantum information processing. Yet, high-order correlations, gN(0),quantifying photon correlation, are still limited to hundreds. Here, we report the generation of a super-bunching light source in photonic crystal fiber with g2(0) reaching 5.86*104 and g5(0) up to 2.72*108, through measuring its photon number probability distributions. under giant g2(0) values, the super-bunching light source presents upturned-tail photon distributions and ubiquitous extreme multi-photon events, where 31 photons from a single light pulse at a mean of 1.99*10-4 photons per pulse have been determined. The probability of this extreme event has been enhanced by 10139 folds compared to a coherent laser with Poissonian distribution. By varying the power of the pumping laser, both photon number distributions and corresponding high-order correlations of this light source can be substantially tailored from Poissonian to super-bunching distributions. These phenomena are attributed to the synchronized nonlinear interactions in photonic crystal fibers pumping by bright squeezed light, and the theoretical simulations agree well with the experimental results. Our research showcases the ability to achieve non-classical light sources with giant high-order correlations and extreme multi-photon events, paving the way for high-order correlation imaging, extreme nonlinear optical effects, quantum information processing, and exploring light-matter interactions with multi-photon physics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.05419v3-abstract-full').style.display = 'none'; document.getElementById('2409.05419v3-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 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 9 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.17048">arXiv:2408.17048</a> <span> [<a href="https://arxiv.org/pdf/2408.17048">pdf</a>, <a href="https://arxiv.org/format/2408.17048">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevA.110.023108">10.1103/PhysRevA.110.023108 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Efficient generation of multiqubit entanglement states using rapid adiabatic passage </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Xu%2C+S">Shijie Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xinwei Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xiangliang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+J">Jinbin Li</a>, <a href="/search/quant-ph?searchtype=author&query=Xue%2C+M">Ming Xue</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="2408.17048v1-abstract-short" style="display: inline;"> We propose the implementation of a rapid adiabatic passage (RAP) scheme to generate entanglement in Rydberg atom-array systems. This method transforms a product state in a multi-qubit system into an entangled state with high fidelity and robustness. By employing global and continuous driving laser fields, we demonstrate the generation of two-qubit Bell state and three-qubit W state, via sequential… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.17048v1-abstract-full').style.display = 'inline'; document.getElementById('2408.17048v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.17048v1-abstract-full" style="display: none;"> We propose the implementation of a rapid adiabatic passage (RAP) scheme to generate entanglement in Rydberg atom-array systems. This method transforms a product state in a multi-qubit system into an entangled state with high fidelity and robustness. By employing global and continuous driving laser fields, we demonstrate the generation of two-qubit Bell state and three-qubit W state, via sequential RAP pulses within the Rydberg blockade regime. As an illustrative example, applying this technique to alkali atoms, we predict fidelities exceeding 0.9995 for two-qubit Bell and three-qubit W state, along with excellent robustness. Furthermore, our scheme can be extended to generate entanglement between weakly coupled atoms and to create four-qubit Greenberger- Horne-Zeilinger states through spatial correlations. Our approach holds the potential for extension to larger atomic arrays, offering a straightforward and efficient method to generate high-fidelity entangled states in neutral atom systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.17048v1-abstract-full').style.display = 'none'; document.getElementById('2408.17048v1-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">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. A 110,023108 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.16274">arXiv:2408.16274</a> <span> [<a href="https://arxiv.org/pdf/2408.16274">pdf</a>, <a href="https://arxiv.org/format/2408.16274">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevA.110.032619">10.1103/PhysRevA.110.032619 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> High-fidelity and robust controlled-Z gates implemented with Rydberg atoms via echoing rapid adiabatic passage </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Xue%2C+M">Ming Xue</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+S">Shijie Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xinwei Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xiangliang 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="2408.16274v1-abstract-short" style="display: inline;"> High-fidelity and robust quantum gates are essential for quantum information processing, where neutral Rydberg atoms trapped in optical tweezer arrays serving as a versatile platform for the implementation. We propose a rapid adiabatic passage (RAP) scheme for achieving a high-fidelity controlled-Z (CZ) gate on a neutral atom Rydberg platform. Utilizing only global laser dressing, our scheme invol… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.16274v1-abstract-full').style.display = 'inline'; document.getElementById('2408.16274v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.16274v1-abstract-full" style="display: none;"> High-fidelity and robust quantum gates are essential for quantum information processing, where neutral Rydberg atoms trapped in optical tweezer arrays serving as a versatile platform for the implementation. We propose a rapid adiabatic passage (RAP) scheme for achieving a high-fidelity controlled-Z (CZ) gate on a neutral atom Rydberg platform. Utilizing only global laser dressing, our scheme involves echoing two identical RAP pulses within the Rydberg blockade regime to realize a CZ gate and can be readily extended to a C$^k$Z gate with additional qubits. We predict a CZ gate with fidelity over 0.9995 using akali-atom parameters, and a CCZ gate with fidelity exceeding 0.999. Moreover, the direct utilization of echoing RAP pulses enables the implementation of a four-bit CCCZ gate at fidelity over 0.996 without further optimization. The proposed scheme, remarkably robust to variations in driving fields and realistic decoherence effects, holds promise for future quantum information processing applications. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.16274v1-abstract-full').style.display = 'none'; document.getElementById('2408.16274v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 29 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">(5+3) pages, 3 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. A 110, 032619 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.13405">arXiv:2408.13405</a> <span> [<a href="https://arxiv.org/pdf/2408.13405">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> <div 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/acs.nanolett.4c03071">10.1021/acs.nanolett.4c03071 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Ultracoherent GHz Diamond Spin-Mechanical Lamb Wave Resonators </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xinzhu Li</a>, <a href="/search/quant-ph?searchtype=author&query=Lekavicius%2C+I">Ignas Lekavicius</a>, <a href="/search/quant-ph?searchtype=author&query=Noeckel%2C+J">Jens Noeckel</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+H">Hailin 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="2408.13405v1-abstract-short" style="display: inline;"> We report the development of an all-optical approach that excites the fundamental compression mode in a diamond Lamb wave resonator with an optical gradient force and detects the induced vibrations via strain coupling to a silicon vacancy center, specifically, via phonon sidebands in the optical excitation spectrum of the silicon vacancy. Sideband optical interferometry has also been used for the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.13405v1-abstract-full').style.display = 'inline'; document.getElementById('2408.13405v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.13405v1-abstract-full" style="display: none;"> We report the development of an all-optical approach that excites the fundamental compression mode in a diamond Lamb wave resonator with an optical gradient force and detects the induced vibrations via strain coupling to a silicon vacancy center, specifically, via phonon sidebands in the optical excitation spectrum of the silicon vacancy. Sideband optical interferometry has also been used for the detection of the in-plane mechanical vibrations, for which conventional optical interferometry is not effective. These experiments demonstrate a GHz fundamental compression mode with a Q-factor >10^7 at temperatures near 7 K, providing a promising platform for reaching the quantum regime of spin mechanics, especially phononic cavity QED of electron spins. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.13405v1-abstract-full').style.display = 'none'; document.getElementById('2408.13405v1-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 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> Nano Letters, 2024 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.12395">arXiv:2408.12395</a> <span> [<a href="https://arxiv.org/pdf/2408.12395">pdf</a>, <a href="https://arxiv.org/format/2408.12395">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/10.1140/epjc/s10052-024-12830-6">10.1140/epjc/s10052-024-12830-6 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Maximal steered coherence in the background of Schwarzschild space-time </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Du%2C+M">Ming-Ming Du</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+H">Hong-Wei Li</a>, <a href="/search/quant-ph?searchtype=author&query=Shen%2C+S">Shu-Ting Shen</a>, <a href="/search/quant-ph?searchtype=author&query=Yan%2C+X">Xiao-Jing Yan</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xi-Yun Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+L">Lan Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Zhong%2C+W">Wei Zhong</a>, <a href="/search/quant-ph?searchtype=author&query=Sheng%2C+Y">Yu-Bo Sheng</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="2408.12395v1-abstract-short" style="display: inline;"> In the past two decades, the exploration of quantumness within Schwarzschild spacetime has garnered significant interest, particularly regarding the Hawking radiation's impact on quantum correlations and quantum coherence. Building on this foundation, we investigate how Hawking radiation influences maximal steered coherence (MSC)-a crucial measure for gauging the ability to generate coherence thro… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.12395v1-abstract-full').style.display = 'inline'; document.getElementById('2408.12395v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.12395v1-abstract-full" style="display: none;"> In the past two decades, the exploration of quantumness within Schwarzschild spacetime has garnered significant interest, particularly regarding the Hawking radiation's impact on quantum correlations and quantum coherence. Building on this foundation, we investigate how Hawking radiation influences maximal steered coherence (MSC)-a crucial measure for gauging the ability to generate coherence through steering. We find that as the Hawking temperature increases, the physically accessible MSC degrade while the unaccessible MSC increase. This observation is attributed to a redistribution of the initial quantum correlations, previously acknowledged by inertial observers, across all bipartite modes. In particular, we find that in limit case that the Hawking temperature tends to infinity, the accessible MSC equals to 1/\sqrt{2} of its initial value, and the unaccessible MSC also equals to the same value. Our findings illuminate the intricate dynamics of quantum information in the vicinity of black holes, suggesting that Hawking radiation plays a pivotal role in reshaping the landscape of quantum coherence and entanglement in curved spacetime. This study not only advances our theoretical understanding of black hole thermodynamics but also opens new avenues for investigating the interface between quantum mechanics and general relativity. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.12395v1-abstract-full').style.display = 'none'; document.getElementById('2408.12395v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 August, 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">4 pages, 1 figure</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.12370">arXiv:2408.12370</a> <span> [<a href="https://arxiv.org/pdf/2408.12370">pdf</a>, <a href="https://arxiv.org/format/2408.12370">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/10.1140/epjc/s10052-024-13164-z">10.1140/epjc/s10052-024-13164-z <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Basis-independent quantum coherence and its distribution under relativistic motion </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Du%2C+M">Ming-Ming Du</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+H">Hong-Wei Li</a>, <a href="/search/quant-ph?searchtype=author&query=Tao%2C+Z">Zhen Tao</a>, <a href="/search/quant-ph?searchtype=author&query=Shen%2C+S">Shu-Ting Shen</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X+Y+X">Xiao-Jing Yan. Xi-Yun Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhong%2C+W">Wei Zhong</a>, <a href="/search/quant-ph?searchtype=author&query=Sheng%2C+Y">Yu-Bo Sheng</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+L">Lan Zhou</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="2408.12370v1-abstract-short" style="display: inline;"> Recent studies have increasingly focused on the effect of relativistic motion on quantum coherence. Prior research predominantly examined the influence of relative motion on basis-dependent quantum coherence, underscoring its susceptibility to decoherence under accelerated conditions. Yet, the effect of relativistic motion on basis-independent quantum coherence, which is critical for understanding… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.12370v1-abstract-full').style.display = 'inline'; document.getElementById('2408.12370v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.12370v1-abstract-full" style="display: none;"> Recent studies have increasingly focused on the effect of relativistic motion on quantum coherence. Prior research predominantly examined the influence of relative motion on basis-dependent quantum coherence, underscoring its susceptibility to decoherence under accelerated conditions. Yet, the effect of relativistic motion on basis-independent quantum coherence, which is critical for understanding the intrinsic quantum features of a system, remains an interesting open question. This paper addresses this question by examining how total, collective, and localized coherence are affected by acceleration and coupling strength. Our analysis reveals that both total and collective coherence significantly decrease with increasing acceleration and coupling strength, ultimately vanishing at high levels of acceleration. This underscores the profound impact of Unruh thermal noise. Conversely, localized coherence exhibits relative stability, decreasing to zero only under the extreme condition of infinite acceleration. Moreover, we demonstrate that collective, localized, and basis-independent coherence collectively satisfy the triangle inequality. These findings are crucial for enhancing our understanding of quantum information dynamics in environments subjected to high acceleration and offer valuable insights on the behavior of quantum coherence under relativistic conditions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.12370v1-abstract-full').style.display = 'none'; document.getElementById('2408.12370v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 August, 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">7 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/2408.10994">arXiv:2408.10994</a> <span> [<a href="https://arxiv.org/pdf/2408.10994">pdf</a>, <a href="https://arxiv.org/format/2408.10994">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Microsatellite-based real-time quantum key distribution </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Cai%2C+W">Wen-Qi Cai</a>, <a href="/search/quant-ph?searchtype=author&query=Ren%2C+J">Ji-Gang Ren</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+C">Chao-Ze Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+M">Meng Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+L">Liang Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+H">Hui-Ying Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Chang%2C+L">Liang Chang</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+J">Jin-Cai Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Jin%2C+B">Biao Jin</a>, <a href="/search/quant-ph?searchtype=author&query=Xue%2C+H">Hua-Jian Xue</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xue-Jiao Li</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+H">Hui Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Yu%2C+G">Guang-Wen Yu</a>, <a href="/search/quant-ph?searchtype=author&query=Tao%2C+X">Xue-Ying Tao</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+T">Ting Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+C">Chong-Fei Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Luo%2C+W">Wen-Bin Luo</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+J">Jie Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Yong%2C+H">Hai-Lin Yong</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yu-Huai Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+F">Feng-Zhi Li</a>, <a href="/search/quant-ph?searchtype=author&query=Jiang%2C+C">Cong Jiang</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+H">Hao-Ze Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+C">Chao Wu</a> , et al. (16 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2408.10994v1-abstract-short" style="display: inline;"> A quantum network provides an infrastructure connecting quantum devices with revolutionary computing, sensing, and communication capabilities. As the best-known application of a quantum network, quantum key distribution (QKD) shares secure keys guaranteed by the laws of quantum mechanics. A quantum satellite constellation offers a solution to facilitate the quantum network on a global scale. The M… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.10994v1-abstract-full').style.display = 'inline'; document.getElementById('2408.10994v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.10994v1-abstract-full" style="display: none;"> A quantum network provides an infrastructure connecting quantum devices with revolutionary computing, sensing, and communication capabilities. As the best-known application of a quantum network, quantum key distribution (QKD) shares secure keys guaranteed by the laws of quantum mechanics. A quantum satellite constellation offers a solution to facilitate the quantum network on a global scale. The Micius satellite has verified the feasibility of satellite quantum communications, however, scaling up quantum satellite constellations is challenging, requiring small lightweight satellites, portable ground stations and real-time secure key exchange. Here we tackle these challenges and report the development of a quantum microsatellite capable of performing space-to-ground QKD using portable ground stations. The quantum microsatellite features a payload weighing approximately 23 kg, while the portable ground station weighs about 100 kg. These weights represent reductions by more than an order and two orders of magnitude, respectively, compared to the Micius satellite. Additionally, we multiplex bidirectional satellite-ground optical communication with quantum communication, enabling key distillation and secure communication in real-time. Using the microsatellite and the portable ground stations, we demonstrate satellite-based QKD with multiple ground stations and achieve the sharing of up to 0.59 million bits of secure keys during a single satellite pass. The compact quantum payload can be readily assembled on existing space stations or small satellites, paving the way for a satellite-constellation-based quantum and classical network for widespread real-life applications. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.10994v1-abstract-full').style.display = 'none'; document.getElementById('2408.10994v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 20 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">40 pages, 8 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.10306">arXiv:2408.10306</a> <span> [<a href="https://arxiv.org/pdf/2408.10306">pdf</a>, <a href="https://arxiv.org/format/2408.10306">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mathematical Physics">math-ph</span> </div> </div> <p class="title is-5 mathjax"> Strict area law entanglement versus chirality </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xiang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+T">Ting-Chun Lin</a>, <a href="/search/quant-ph?searchtype=author&query=McGreevy%2C+J">John McGreevy</a>, <a href="/search/quant-ph?searchtype=author&query=Shi%2C+B">Bowen 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="2408.10306v1-abstract-short" style="display: inline;"> Chirality is a property of a gapped phase of matter in two spatial dimensions that can be manifested through non-zero thermal or electrical Hall conductance. In this paper, we prove two no-go theorems that forbid such chirality for a quantum state in a finite dimensional local Hilbert space with strict area law entanglement entropies. As a crucial ingredient in the proofs, we introduce a new quant… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.10306v1-abstract-full').style.display = 'inline'; document.getElementById('2408.10306v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.10306v1-abstract-full" style="display: none;"> Chirality is a property of a gapped phase of matter in two spatial dimensions that can be manifested through non-zero thermal or electrical Hall conductance. In this paper, we prove two no-go theorems that forbid such chirality for a quantum state in a finite dimensional local Hilbert space with strict area law entanglement entropies. As a crucial ingredient in the proofs, we introduce a new quantum information-theoretic primitive called instantaneous modular flow, which has many other potential applications. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.10306v1-abstract-full').style.display = 'none'; document.getElementById('2408.10306v1-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">5+9 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/2408.09783">arXiv:2408.09783</a> <span> [<a href="https://arxiv.org/pdf/2408.09783">pdf</a>, <a href="https://arxiv.org/format/2408.09783">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 metrological capability as a probe for quantum phase transition </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xiangbei Li</a>, <a href="/search/quant-ph?searchtype=author&query=Chu%2C+Y">Yaoming Chu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+S">Shaoliang Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Cai%2C+J">Jianming Cai</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="2408.09783v3-abstract-short" style="display: inline;"> The comprehension of quantum phase transitions (QPTs) is considered as a critical foothold in the field of many-body physics. Developing protocols to effectively identify and understand QPTs thus represents a key but challenging task for present quantum simulation experiments. Here, we establish a dynamical quench-interferometric framework to probe a zero-temperature QPT, which utilizes the evolve… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.09783v3-abstract-full').style.display = 'inline'; document.getElementById('2408.09783v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.09783v3-abstract-full" style="display: none;"> The comprehension of quantum phase transitions (QPTs) is considered as a critical foothold in the field of many-body physics. Developing protocols to effectively identify and understand QPTs thus represents a key but challenging task for present quantum simulation experiments. Here, we establish a dynamical quench-interferometric framework to probe a zero-temperature QPT, which utilizes the evolved state by quenching the QPT Hamiltonian as input of a unitary interferometer. The metrological capability quantified by the quantum Fisher information captivatingly shows an unique peak in the vicinity of the quantum critical point, allowing us to probe the QPT without cooling the system to its ground state. We show that the probing can be implemented by extracting quantum fluctuations of the interferometric generator as well as parameter estimation uncertainty of the interferometric phase, and subsequently allows identifying the boundary of the phase diagram. Our results establish an important link between QPTs and quantum metrology, and enrich the toolbox of studying non-equilibrium many-body physics in current quantum simulators. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.09783v3-abstract-full').style.display = 'none'; document.getElementById('2408.09783v3-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 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 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">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/2408.08429">arXiv:2408.08429</a> <span> [<a href="https://arxiv.org/pdf/2408.08429">pdf</a>, <a href="https://arxiv.org/ps/2408.08429">ps</a>, <a href="https://arxiv.org/format/2408.08429">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Theory">hep-th</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mathematical Physics">math-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> SLOCC and LU classification of black holes with eight electric and magnetic charges </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+D">Dafa Li</a>, <a href="/search/quant-ph?searchtype=author&query=Cheng%2C+M">Maggie Cheng</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xiangrong Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shuwang 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="2408.08429v1-abstract-short" style="display: inline;"> In \cite{Linde}, Kallosh and Linde discussed the SLOCC classification of black holes. However, the criteria for the SLOCC classification of black holes have not been given. In addition, the LU classification of black holes has not been studied in the past. In this paper we will consider both SLOCC and LU classification of the STU black holes with four integer electric charges $q_{i} $ and four int… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.08429v1-abstract-full').style.display = 'inline'; document.getElementById('2408.08429v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.08429v1-abstract-full" style="display: none;"> In \cite{Linde}, Kallosh and Linde discussed the SLOCC classification of black holes. However, the criteria for the SLOCC classification of black holes have not been given. In addition, the LU classification of black holes has not been studied in the past. In this paper we will consider both SLOCC and LU classification of the STU black holes with four integer electric charges $q_{i} $ and four integer magnetic charges $p^{i}$, $i=0,1,2,3$. Two STU black holes with eight charges are considered SLOCC (LU) equivalent if and only if their corresponding states of three qubits are SLOCC (LU) equivalent. Under this definition, we give criteria for the classification of the eight-charge STU black holes under SLOCC and under LU, respectively. We will study the classification of the black holes via the classification of SLOCC and LU entanglement of three qubits. We then identify a set of black holes corresponding to the state W of three qubits, which is of interest since it has the maximal average von Neumann entropy of entanglement. Via von Neumann entanglement entropy, we partition the STU black holes corresponding to pure states of GHZ SLOCC class into five families under LU. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.08429v1-abstract-full').style.display = 'none'; document.getElementById('2408.08429v1-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 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> Int J theor phys 63, issue 6, 144 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.05907">arXiv:2408.05907</a> <span> [<a href="https://arxiv.org/pdf/2408.05907">pdf</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"> Cryogenic nonlinear conversion processes in periodically-poled thin-film lithium niobate waveguides </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Cheng%2C+Y">Yujie Cheng</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xiaoting Li</a>, <a href="/search/quant-ph?searchtype=author&query=Feng%2C+L">Lantian Feng</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+H">Haochuan Li</a>, <a href="/search/quant-ph?searchtype=author&query=Sun%2C+W">Wenzhao Sun</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+X">Xinyu Song</a>, <a href="/search/quant-ph?searchtype=author&query=Ding%2C+Y">Yuyang Ding</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+G">Guangcan Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+C">Cheng Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Ren%2C+X">Xifeng Ren</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2408.05907v1-abstract-short" style="display: inline;"> Periodically poled thin-film lithium niobate (TFLN) waveguides, which enable efficient quadratic nonlinear processes, serve as crucial foundation for classical and quantum signal processing with photonic integrated circuits. To expand their application scope, we provide, to our best knowledge, the first investigation of nonlinear conversion processes in periodically poled TFLN waveguides at cryoge… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.05907v1-abstract-full').style.display = 'inline'; document.getElementById('2408.05907v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.05907v1-abstract-full" style="display: none;"> Periodically poled thin-film lithium niobate (TFLN) waveguides, which enable efficient quadratic nonlinear processes, serve as crucial foundation for classical and quantum signal processing with photonic integrated circuits. To expand their application scope, we provide, to our best knowledge, the first investigation of nonlinear conversion processes in periodically poled TFLN waveguides at cryogenic condition. Through systematic experimental characterization, we find that the periodically poled TFLN waveguide maintains consistent conversion efficiencies at both cryogenic and room temperatures for both classical second-harmonic generation and quantum photon-pair generation processes, demonstrating the significant potential of TFLN wavelength conversion devices for cryogenic applications. This breakthrough will foster future scalable quantum photonic systems and optical interfacing among different cryogenic platforms. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.05907v1-abstract-full').style.display = 'none'; document.getElementById('2408.05907v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.03987">arXiv:2408.03987</a> <span> [<a href="https://arxiv.org/pdf/2408.03987">pdf</a>, <a href="https://arxiv.org/format/2408.03987">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"> Double-bracket quantum algorithms for high-fidelity ground state preparation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Robbiati%2C+M">Matteo Robbiati</a>, <a href="/search/quant-ph?searchtype=author&query=Pedicillo%2C+E">Edoardo Pedicillo</a>, <a href="/search/quant-ph?searchtype=author&query=Pasquale%2C+A">Andrea Pasquale</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xiaoyue Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wright%2C+A">Andrew Wright</a>, <a href="/search/quant-ph?searchtype=author&query=Farias%2C+R+M+S">Renato M. S. Farias</a>, <a href="/search/quant-ph?searchtype=author&query=Giang%2C+K+U">Khanh Uyen Giang</a>, <a href="/search/quant-ph?searchtype=author&query=Son%2C+J">Jeongrak Son</a>, <a href="/search/quant-ph?searchtype=author&query=Kn%C3%B6rzer%2C+J">Johannes Kn枚rzer</a>, <a href="/search/quant-ph?searchtype=author&query=Goh%2C+S+T">Siong Thye Goh</a>, <a href="/search/quant-ph?searchtype=author&query=Khoo%2C+J+Y">Jun Yong Khoo</a>, <a href="/search/quant-ph?searchtype=author&query=Ng%2C+N+H+Y">Nelly H. Y. Ng</a>, <a href="/search/quant-ph?searchtype=author&query=Holmes%2C+Z">Zo毛 Holmes</a>, <a href="/search/quant-ph?searchtype=author&query=Carrazza%2C+S">Stefano Carrazza</a>, <a href="/search/quant-ph?searchtype=author&query=Gluza%2C+M">Marek Gluza</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="2408.03987v1-abstract-short" style="display: inline;"> Ground state preparation is a key area where quantum computers are expected to prove advantageous. Double-bracket quantum algorithms (DBQAs) have been recently proposed to diagonalize Hamiltonians and in this work we show how to use them to prepare ground states. We propose to improve an initial state preparation by adding a few steps of DBQAs. The interfaced method systematically achieves a bette… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.03987v1-abstract-full').style.display = 'inline'; document.getElementById('2408.03987v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.03987v1-abstract-full" style="display: none;"> Ground state preparation is a key area where quantum computers are expected to prove advantageous. Double-bracket quantum algorithms (DBQAs) have been recently proposed to diagonalize Hamiltonians and in this work we show how to use them to prepare ground states. We propose to improve an initial state preparation by adding a few steps of DBQAs. The interfaced method systematically achieves a better fidelity while significantly reducing the computational cost of the procedure. For a Heisenberg model, we compile our algorithm using CZ and single-qubit gates into circuits that match capabilities of near-term quantum devices. Moreover, we show that DBQAs can benefit from the experimental availability of increasing circuit depths. Whenever an approximate ground state can be prepared without exhausting the available circuit depth, then DBQAs can be enlisted to algorithmically seek a higher fidelity preparation. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.03987v1-abstract-full').style.display = 'none'; document.getElementById('2408.03987v1-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 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">5 pages + appendix, 4 figures, code available at: https://github.com/qiboteam/boostvqe</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> TIF-UNIMI-2024-6 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.01769">arXiv:2408.01769</a> <span> [<a href="https://arxiv.org/pdf/2408.01769">pdf</a>, <a href="https://arxiv.org/format/2408.01769">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"> Transform Arbitrary Good Quantum LDPC Codes into Good Geometrically Local Codes in Any Dimension </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xingjian Li</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+T">Ting-Chun Lin</a>, <a href="/search/quant-ph?searchtype=author&query=Hsieh%2C+M">Min-Hsiu Hsieh</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="2408.01769v1-abstract-short" style="display: inline;"> Geometrically local quantum codes, comprised of qubits and checks embedded in $\mathbb{R}^D$ with local check operators, have been a subject of significant interest. A key challenge is identifying the optimal code construction that maximizes both dimension and distance. Recent advancements have produced several constructions, but these either depend on specific good quantum low-density parity-chec… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.01769v1-abstract-full').style.display = 'inline'; document.getElementById('2408.01769v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.01769v1-abstract-full" style="display: none;"> Geometrically local quantum codes, comprised of qubits and checks embedded in $\mathbb{R}^D$ with local check operators, have been a subject of significant interest. A key challenge is identifying the optimal code construction that maximizes both dimension and distance. Recent advancements have produced several constructions, but these either depend on specific good quantum low-density parity-check (qLDPC) codes or are limited to three dimensions. In this work, we introduce a construction that can transform any good qLDPC code into an optimal geometrically local quantum code. Our approach hinges on a novel procedure that extracts a two-dimensional structure from an arbitrary three-term chain complex. We expect that this procedure will find broader applications in areas such as weight reduction and the geometric realization of chain complexes. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.01769v1-abstract-full').style.display = 'none'; document.getElementById('2408.01769v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 3 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">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">25 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/2407.15182">arXiv:2407.15182</a> <span> [<a href="https://arxiv.org/pdf/2407.15182">pdf</a>, <a href="https://arxiv.org/format/2407.15182">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"> Thermometry of Trapped Ions Based on Bichromatic Driving </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xie-Qian Li</a>, <a href="/search/quant-ph?searchtype=author&query=Tao%2C+Y">Yi Tao</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+T">Ting Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+W">Wei Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Xie%2C+Y">Yi Xie</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+C">Chun-Wang Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+P">Ping-Xing Chen</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2407.15182v1-abstract-short" style="display: inline;"> Accurate thermometry of laser-cooled ions is crucial for the performance of the trapped-ions quantum computing platform. However, most existing methods face a computational exponential bottleneck. Recently, a thermometry method based on bichromatic driving was theoretically proposed by Ivan Vybornyi et al. to overcome this obstacle, which allows the computational complexity to remain constant with… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.15182v1-abstract-full').style.display = 'inline'; document.getElementById('2407.15182v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.15182v1-abstract-full" style="display: none;"> Accurate thermometry of laser-cooled ions is crucial for the performance of the trapped-ions quantum computing platform. However, most existing methods face a computational exponential bottleneck. Recently, a thermometry method based on bichromatic driving was theoretically proposed by Ivan Vybornyi et al. to overcome this obstacle, which allows the computational complexity to remain constant with the increase of ion numbers. In this paper, we provide a detailed statistical analysis of this method and prove its robustness to several imperfect experimental conditions using Floquet theory. We then experimentally verify its good performance on a linear segmented surface-electrode ion trap platform for the first time. This method is proven to be effective from near the motional ground state to a few mean phonon numbers. Our theoretical analysis and experimental verification demonstrate that the scheme can accurately and efficiently measure the temperature in ion crystals. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.15182v1-abstract-full').style.display = 'none'; document.getElementById('2407.15182v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.15102">arXiv:2407.15102</a> <span> [<a href="https://arxiv.org/pdf/2407.15102">pdf</a>, <a href="https://arxiv.org/format/2407.15102">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Experimental demonstration of reconstructing quantum states with generative models </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xuegang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Jiang%2C+W">Wenjie Jiang</a>, <a href="/search/quant-ph?searchtype=author&query=Hua%2C+Z">Ziyue Hua</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+W">Weiting Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Pan%2C+X">Xiaoxuan Pan</a>, <a href="/search/quant-ph?searchtype=author&query=Cai%2C+W">Weizhou Cai</a>, <a href="/search/quant-ph?searchtype=author&query=Lu%2C+Z">Zhide Lu</a>, <a href="/search/quant-ph?searchtype=author&query=Han%2C+J">Jiaxiu Han</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+R">Rebing Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Zou%2C+C">Chang-Ling Zou</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+D">Dong-Ling Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Sun%2C+L">Luyan 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="2407.15102v1-abstract-short" style="display: inline;"> Quantum state tomography, a process that reconstructs a quantum state from measurements on an ensemble of identically prepared copies, plays a crucial role in benchmarking quantum devices. However, brute-force approaches to quantum state tomography would become impractical for large systems, as the required resources scale exponentially with the system size. Here, we explore a machine learning app… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.15102v1-abstract-full').style.display = 'inline'; document.getElementById('2407.15102v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.15102v1-abstract-full" style="display: none;"> Quantum state tomography, a process that reconstructs a quantum state from measurements on an ensemble of identically prepared copies, plays a crucial role in benchmarking quantum devices. However, brute-force approaches to quantum state tomography would become impractical for large systems, as the required resources scale exponentially with the system size. Here, we explore a machine learning approach and report an experimental demonstration of reconstructing quantum states based on neural network generative models with an array of programmable superconducting transmon qubits. In particular, we experimentally prepare the Greenberger-Horne-Zeilinger states and random states up to five qubits and demonstrate that the machine learning approach can efficiently reconstruct these states with the number of required experimental samples scaling linearly with system size. Our results experimentally showcase the intriguing potential for exploiting machine learning techniques in validating and characterizing complex quantum devices, offering a valuable guide for the future development of quantum technologies. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.15102v1-abstract-full').style.display = 'none'; document.getElementById('2407.15102v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.11851">arXiv:2407.11851</a> <span> [<a href="https://arxiv.org/pdf/2407.11851">pdf</a>, <a href="https://arxiv.org/ps/2407.11851">ps</a>, <a href="https://arxiv.org/format/2407.11851">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"> Atom Cavity Encoding for NP-Complete Problems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Ye%2C+M">Meng Ye</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xiaopeng 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="2407.11851v1-abstract-short" style="display: inline;"> We consider an atom-cavity system having long-range atomic interactions mediated by cavity modes. It has been shown that quantum simulations of spin models with this system can naturally be used to solve number partition problems. Here, we present encoding schemes for numerous NP-complete problems, encompassing the majority of Karp's 21 NP-complete problems. We find a number of such computation pr… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.11851v1-abstract-full').style.display = 'inline'; document.getElementById('2407.11851v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.11851v1-abstract-full" style="display: none;"> We consider an atom-cavity system having long-range atomic interactions mediated by cavity modes. It has been shown that quantum simulations of spin models with this system can naturally be used to solve number partition problems. Here, we present encoding schemes for numerous NP-complete problems, encompassing the majority of Karp's 21 NP-complete problems. We find a number of such computation problems can be encoded by the atom-cavity system at a linear cost of atom number. There are still certain problems that cannot be encoded by the atom-cavity as efficiently, such as quadratic unconstrained binary optimization (QUBO), and the Hamiltonian cycle. For these problems, we provide encoding schemes with a quadratic or quartic cost in the atom number. We expect this work to provide important guidance to search for the practical quantum advantage of the atom-cavity system in solving NP-complete problems. Moreover, the encoding schemes we develop here may also be adopted in other optical systems for solving NP-complete problems, where a similar form of Mattis-type spin glass Hamiltonian as in the atom-cavity system can be implemented. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.11851v1-abstract-full').style.display = 'none'; document.getElementById('2407.11851v1-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 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">25 pages, 1 table</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.10523">arXiv:2407.10523</a> <span> [<a href="https://arxiv.org/pdf/2407.10523">pdf</a>, <a href="https://arxiv.org/format/2407.10523">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="Chemical Physics">physics.chem-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1063/5.0228731">10.1063/5.0228731 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Variational Quantum Imaginary Time Evolution for Matrix Product State Ansatz with Tests on Transcorrelated Hamiltonians </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+H">Hao-En Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xiang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+J">Jia-Cheng Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+G">Guang-Ze Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Shen%2C+Z">Zhu-Ping Shen</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+C">Chen Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+J">Jun Li</a>, <a href="/search/quant-ph?searchtype=author&query=Hu%2C+H">Han-Shi Hu</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="2407.10523v2-abstract-short" style="display: inline;"> The matrix product state (MPS) ansatz offers a promising approach for finding the ground state of molecular Hamiltonians and solving quantum chemistry problems. Building on this concept, the proposed technique of quantum circuit MPS (QCMPS) enables the simulation of chemical systems using a relatively small number of qubits. In this study, we enhance the optimization performance of the QCMPS ansat… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.10523v2-abstract-full').style.display = 'inline'; document.getElementById('2407.10523v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.10523v2-abstract-full" style="display: none;"> The matrix product state (MPS) ansatz offers a promising approach for finding the ground state of molecular Hamiltonians and solving quantum chemistry problems. Building on this concept, the proposed technique of quantum circuit MPS (QCMPS) enables the simulation of chemical systems using a relatively small number of qubits. In this study, we enhance the optimization performance of the QCMPS ansatz by employing the variational quantum imaginary time evolution (VarQITE) approach. Guided by McLachlan's variational principle, the VarQITE method provides analytical metrics and gradients, resulting in improved convergence efficiency and robustness of the QCMPS. We validate these improvements numerically through simulations of $\rm H_2$, $\rm H_4$, and $\rm LiH$ molecules. Additionally, given that VarQITE is applicable to non-Hermitian Hamiltonians, we evaluate its effectiveness in preparing the ground state of transcorrelated (TC) Hamiltonians. This approach yields energy estimates comparable to the complete basis set (CBS) limit while using even fewer qubits. Specifically, we perform simulations of the beryllium atom and $\rm LiH$ molecule using only three qubits, maintaining high fidelity with the CBS ground state energy of these systems. This qubit reduction is achieved through the combined advantages of both the QCMPS ansatz and transcorrelation. Our findings demonstrate the potential practicality of this quantum chemistry algorithm on near-term quantum devices. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.10523v2-abstract-full').style.display = 'none'; document.getElementById('2407.10523v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 1 October, 2024; <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">15 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/2407.09227">arXiv:2407.09227</a> <span> [<a href="https://arxiv.org/pdf/2407.09227">pdf</a>, <a href="https://arxiv.org/format/2407.09227">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Gases">cond-mat.quant-gas</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Stability and decay of subradiant patterns in a quantum gas with photon-mediated interactions </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Baumg%C3%A4rtner%2C+A">Alexander Baumg盲rtner</a>, <a href="/search/quant-ph?searchtype=author&query=Hertlein%2C+S">Simon Hertlein</a>, <a href="/search/quant-ph?searchtype=author&query=Schmit%2C+T">Tom Schmit</a>, <a href="/search/quant-ph?searchtype=author&query=Dreon%2C+D">Davide Dreon</a>, <a href="/search/quant-ph?searchtype=author&query=M%C3%A1ximo%2C+C">Carlos M谩ximo</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xiangliang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Morigi%2C+G">Giovanna Morigi</a>, <a href="/search/quant-ph?searchtype=author&query=Donner%2C+T">Tobias Donner</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="2407.09227v1-abstract-short" style="display: inline;"> The phenomenon of subradiance, marked by its surprising suppression of spontaneous emission, challenges conventional expectations of the collective behavior of scatterers. We study subradiance in the experimental setting of a Bose-Einstein condensate positioned at the mode crossing of two optical cavities. In this setup, subradiance manifests in the form of metastable density structures that suppr… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.09227v1-abstract-full').style.display = 'inline'; document.getElementById('2407.09227v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.09227v1-abstract-full" style="display: none;"> The phenomenon of subradiance, marked by its surprising suppression of spontaneous emission, challenges conventional expectations of the collective behavior of scatterers. We study subradiance in the experimental setting of a Bose-Einstein condensate positioned at the mode crossing of two optical cavities. In this setup, subradiance manifests in the form of metastable density structures that suppress emission into one cavity mode, thereby preventing relaxation to the stationary, superradiant grating that minimizes the system's energy. We observe lifetimes of the subradiant states exceeding hundred milliseconds, far surpassing any characteristic dynamic time scale of the system. Eventually, an instability triggers a rapid transition to the superradiant stationary pattern. We reproduce these dynamics by a quantum mean field model, suggesting that subradiance shares characteristics with quasi-stationary states predicted in other long-range interacting systems such as astrophysical clusters and plasmas. This behavior highlights the potential of photon-mediated long-range forces as controllable and exploitable quantum cooperative phenomenon. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.09227v1-abstract-full').style.display = 'none'; document.getElementById('2407.09227v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.06253">arXiv:2407.06253</a> <span> [<a href="https://arxiv.org/pdf/2407.06253">pdf</a>, <a href="https://arxiv.org/format/2407.06253">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Disordered Systems and Neural Networks">cond-mat.dis-nn</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Unsupervised machine learning for detecting mutual independence among eigenstate regimes in interacting quasiperiodic chains </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Beveridge%2C+C">Colin Beveridge</a>, <a href="/search/quant-ph?searchtype=author&query=Hart%2C+K">Kathleen Hart</a>, <a href="/search/quant-ph?searchtype=author&query=Cristani%2C+C+R">Cassio Rodrigo Cristani</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xiao Li</a>, <a href="/search/quant-ph?searchtype=author&query=Barbierato%2C+E">Enrico Barbierato</a>, <a href="/search/quant-ph?searchtype=author&query=Hsu%2C+Y">Yi-Ting Hsu</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="2407.06253v2-abstract-short" style="display: inline;"> Many-body eigenstates that are neither thermal nor many-body-localized (MBL) were numerically found in certain interacting chains with moderate quasiperiodic potentials. The energy regime consisting of these non-ergodic but extended (NEE) eigenstates has been extensively studied for being a possible many-body mobility edge between the energy-resolved MBL and thermal phases. Recently, the NEE regim… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.06253v2-abstract-full').style.display = 'inline'; document.getElementById('2407.06253v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.06253v2-abstract-full" style="display: none;"> Many-body eigenstates that are neither thermal nor many-body-localized (MBL) were numerically found in certain interacting chains with moderate quasiperiodic potentials. The energy regime consisting of these non-ergodic but extended (NEE) eigenstates has been extensively studied for being a possible many-body mobility edge between the energy-resolved MBL and thermal phases. Recently, the NEE regime was further proposed to be a prethermal phenomenon that generally occurs when different operators spread at sizably different timescales. Here, we numerically examine the mutual independence among the NEE, MBL, and thermal regimes in the lens of eigenstate entanglement spectra (ES). Given the complexity and rich information embedded in ES, we develop an unsupervised learning approach that is designed to quantify the mutual independence among general phases. Our method is first demonstrated on an illustrative toy example that uses RGB color data to represent phases, then applied to the ES of an interacting generalized Aubry Andre model from weak to strong potential strength. We find that while the MBL and thermal regimes are mutually independent, the NEE regime is dependent on the former two and smoothly appears as the potential strength decreases. We attribute our numerically finding to the fact that the ES data in the NEE regime exhibits both an MBL-like fast decay and a thermal-like long tail. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.06253v2-abstract-full').style.display = 'none'; document.getElementById('2407.06253v2-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 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 8 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">6 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/2407.05455">arXiv:2407.05455</a> <span> [<a href="https://arxiv.org/pdf/2407.05455">pdf</a>, <a href="https://arxiv.org/format/2407.05455">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="Quantum Gases">cond-mat.quant-gas</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Statistical Mechanics">cond-mat.stat-mech</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Quantum Supercritical Crossovers with Dynamical Singularity </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wang%2C+J">Junsen Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Lv%2C+E">Enze Lv</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xinyang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Jin%2C+Y">Yuliang Jin</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+W">Wei 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="2407.05455v2-abstract-short" style="display: inline;"> Supercriticality, characterized by strong fluctuations and a wealth of phenomena, emerges as an intriguing state beyond the classical liquid-gas critical point. In this study, we extend this notable concept to quantum many-body systems near the quantum critical point, by studying the quantum Ising model and Rydberg atom array through tensor network calculations and scaling analyses. We find two su… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.05455v2-abstract-full').style.display = 'inline'; document.getElementById('2407.05455v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.05455v2-abstract-full" style="display: none;"> Supercriticality, characterized by strong fluctuations and a wealth of phenomena, emerges as an intriguing state beyond the classical liquid-gas critical point. In this study, we extend this notable concept to quantum many-body systems near the quantum critical point, by studying the quantum Ising model and Rydberg atom array through tensor network calculations and scaling analyses. We find two supercritical crossover lines in the quantum phase diagram with universal scaling, $h \propto (g - g_c)^{尾+ 纬}$, where $g$ ($h$) is the transverse (longitudinal) field, $g_c$ is the critical field, and $尾, 纬$ are the related critical exponents. Enclosed by the two crossover lines, there exist supercritical quantum states with universal behaviors in correlations and entanglement. In particular, we reveal a dynamical quantum phase transition occurring when traversing the quantum supercritical crossover line. These dynamical singularities, attributed to the intersection of Lee-Yang-Fisher zero lines with the real-time axis, have no counterpart in classical supercriticality. We propose that the Rydberg atom array offers an ideal platform for studying the quantum supercritical crossovers and measuring the critical exponents. The present work establishes a foundation for exploring quantum supercriticality and related phenomena in correlated many-body systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.05455v2-abstract-full').style.display = 'none'; document.getElementById('2407.05455v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 19 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 7 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">Major revision, to be resubmit to PRL. 6 pages, 4 figures (SM 2 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/2407.02787">arXiv:2407.02787</a> <span> [<a href="https://arxiv.org/pdf/2407.02787">pdf</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"> A versatile quantum microwave photonic signal processing platform based on coincidence window selection technique </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xinghua Li</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Y">Yifan Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Xiang%2C+X">Xiao Xiang</a>, <a href="/search/quant-ph?searchtype=author&query=Quan%2C+R">Runai Quan</a>, <a href="/search/quant-ph?searchtype=author&query=Cao%2C+M">Mingtao Cao</a>, <a href="/search/quant-ph?searchtype=author&query=Dong%2C+R">Ruifang Dong</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+T">Tao Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+M">Ming Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+S">Shougang 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="2407.02787v1-abstract-short" style="display: inline;"> Quantum microwave photonics (QMWP) is an innovative approach that combines energy-time entangled biphoton sources as the optical carrier with time-correlated single-photon detection for high-speed RF signal recovery. This groundbreaking method offers unique advantages such as nonlocal RF signal encoding and robust resistance to dispersion-induced frequency fading. This paper explores the versatili… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.02787v1-abstract-full').style.display = 'inline'; document.getElementById('2407.02787v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.02787v1-abstract-full" style="display: none;"> Quantum microwave photonics (QMWP) is an innovative approach that combines energy-time entangled biphoton sources as the optical carrier with time-correlated single-photon detection for high-speed RF signal recovery. This groundbreaking method offers unique advantages such as nonlocal RF signal encoding and robust resistance to dispersion-induced frequency fading. This paper explores the versatility of processing the quantum microwave photonic signal by utilizing coincidence window selection on the biphoton coincidence distribution. The demonstration includes finely-tunable RF phase shifting, flexible multi-tap transversal filtering (with up to 15 taps), and photonically implemented RF mixing, leveraging the nonlocal RF mapping characteristic of QMWP. These accomplishments significantly enhance the capability of microwave photonic systems in processing ultra-weak signals, opening up new possibilities for various applications. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.02787v1-abstract-full').style.display = 'none'; document.getElementById('2407.02787v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 2 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.02774">arXiv:2407.02774</a> <span> [<a href="https://arxiv.org/pdf/2407.02774">pdf</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"> Quantum microwave photonic mixer with a large spurious-free dynamic range </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xinghua Li</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Y">Yifan Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Xiang%2C+X">Xiao Xiang</a>, <a href="/search/quant-ph?searchtype=author&query=Quan%2C+R">Runai Quan</a>, <a href="/search/quant-ph?searchtype=author&query=Cao%2C+M">Mingtao Cao</a>, <a href="/search/quant-ph?searchtype=author&query=Dong%2C+R">Ruifang Dong</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+T">Tao Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+M">Ming Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+S">Shougang 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="2407.02774v1-abstract-short" style="display: inline;"> As one of the most fundamental functionalities of microwave photonics, microwave frequency mixing plays an essential role in modern radars and wireless communication systems. However, the commonly utilized intensity modulation in the systems often leads to inadequate spurious-free dynamic range (SFDR) for many sought-after applications. Quantum microwave photonics technique offers a promising solu… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.02774v1-abstract-full').style.display = 'inline'; document.getElementById('2407.02774v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.02774v1-abstract-full" style="display: none;"> As one of the most fundamental functionalities of microwave photonics, microwave frequency mixing plays an essential role in modern radars and wireless communication systems. However, the commonly utilized intensity modulation in the systems often leads to inadequate spurious-free dynamic range (SFDR) for many sought-after applications. Quantum microwave photonics technique offers a promising solution for improving SFDR in terms of higher-order harmonic distortion. In this paper, we demonstrate two types of quantum microwave photonic mixers based on the configuration of the intensity modulators: cascade-type and parallel-type. Leveraging the nonlocal RF signal encoding capability, both types of quantum microwave photonic mixers not only exhibit the advantage of dual-channel output but also present significant improvement in SFDR. Specifically, the parallel-type quantum microwave photonic mixer achieves a remarkable SFDR value of 113.6 dB.Hz1/2, which is 30 dB better than that of the cascade-type quantum microwave photonic mixer. When compared to the classical microwave photonic mixer, this enhancement reaches a notable 53.6 dB at the expense of 8 dB conversion loss. These results highlight the superiority of quantum microwave photonic mixers in the fields of microwave and millimeter-wave systems. Further applying multi-photon frequency entangled sources as optical carriers, the dual-channel microwave frequency conversion capability endowed by the quantum microwave photonic mixer can be extended to enhance the performance of multiple-paths microwave mixing which is essential for radar net systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.02774v1-abstract-full').style.display = 'none'; document.getElementById('2407.02774v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 2 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2406.17248">arXiv:2406.17248</a> <span> [<a href="https://arxiv.org/pdf/2406.17248">pdf</a>, <a href="https://arxiv.org/format/2406.17248">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"> MindSpore Quantum: A User-Friendly, High-Performance, and AI-Compatible Quantum Computing Framework </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Xu%2C+X">Xusheng Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Cui%2C+J">Jiangyu Cui</a>, <a href="/search/quant-ph?searchtype=author&query=Cui%2C+Z">Zidong Cui</a>, <a href="/search/quant-ph?searchtype=author&query=He%2C+R">Runhong He</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Q">Qingyu Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xiaowei Li</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+Y">Yanling Lin</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+J">Jiale Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+W">Wuxin Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Lu%2C+J">Jiale Lu</a>, <a href="/search/quant-ph?searchtype=author&query=Luo%2C+M">Maolin Luo</a>, <a href="/search/quant-ph?searchtype=author&query=Lyu%2C+C">Chufan Lyu</a>, <a href="/search/quant-ph?searchtype=author&query=Pan%2C+S">Shijie Pan</a>, <a href="/search/quant-ph?searchtype=author&query=Pavel%2C+M">Mosharev Pavel</a>, <a href="/search/quant-ph?searchtype=author&query=Shu%2C+R">Runqiu Shu</a>, <a href="/search/quant-ph?searchtype=author&query=Tang%2C+J">Jialiang Tang</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+R">Ruoqian Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+S">Shu Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+K">Kang Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Yu%2C+F">Fan Yu</a>, <a href="/search/quant-ph?searchtype=author&query=Zeng%2C+Q">Qingguo Zeng</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+H">Haiying Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Zheng%2C+Q">Qiang Zheng</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+J">Junyuan Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+X">Xu Zhou</a> , et al. (14 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2406.17248v3-abstract-short" style="display: inline;"> We introduce MindSpore Quantum, a pioneering hybrid quantum-classical framework with a primary focus on the design and implementation of noisy intermediate-scale quantum (NISQ) algorithms. Leveraging the robust support of MindSpore, an advanced open-source deep learning training/inference framework, MindSpore Quantum exhibits exceptional efficiency in the design and training of variational quantum… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.17248v3-abstract-full').style.display = 'inline'; document.getElementById('2406.17248v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2406.17248v3-abstract-full" style="display: none;"> We introduce MindSpore Quantum, a pioneering hybrid quantum-classical framework with a primary focus on the design and implementation of noisy intermediate-scale quantum (NISQ) algorithms. Leveraging the robust support of MindSpore, an advanced open-source deep learning training/inference framework, MindSpore Quantum exhibits exceptional efficiency in the design and training of variational quantum algorithms on both CPU and GPU platforms, delivering remarkable performance. Furthermore, this framework places a strong emphasis on enhancing the operational efficiency of quantum algorithms when executed on real quantum hardware. This encompasses the development of algorithms for quantum circuit compilation and qubit mapping, crucial components for achieving optimal performance on quantum processors. In addition to the core framework, we introduce QuPack, a meticulously crafted quantum computing acceleration engine. QuPack significantly accelerates the simulation speed of MindSpore Quantum, particularly in variational quantum eigensolver (VQE), quantum approximate optimization algorithm (QAOA), and tensor network simulations, providing astonishing speed. This combination of cutting-edge technologies empowers researchers and practitioners to explore the frontiers of quantum computing with unprecedented efficiency and performance. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.17248v3-abstract-full').style.display = 'none'; document.getElementById('2406.17248v3-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 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 24 June, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2406.11291">arXiv:2406.11291</a> <span> [<a href="https://arxiv.org/pdf/2406.11291">pdf</a>, <a href="https://arxiv.org/ps/2406.11291">ps</a>, <a href="https://arxiv.org/format/2406.11291">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/10.1063/5.0211177">10.1063/5.0211177 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Simulation of chiral motion of excitation within the ground-state manifolds of neutral atoms </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Tang%2C+H">Hao-Yuan Tang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xiao-Xuan Li</a>, <a href="/search/quant-ph?searchtype=author&query=You%2C+J">Jia-Bin You</a>, <a href="/search/quant-ph?searchtype=author&query=Shao%2C+X">Xiao-Qiang Shao</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2406.11291v2-abstract-short" style="display: inline;"> Laser-induced gauge fields in neutral atoms serve as a means of mimicking the effects of a magnetic field, providing researchers with a platform to explore behaviors analogous to those observed in condensed matter systems under real magnetic fields. Here, we propose a method to generate chiral motion in atomic excitations within the neutral atomic ground-state manifolds. This is achieved through t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.11291v2-abstract-full').style.display = 'inline'; document.getElementById('2406.11291v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2406.11291v2-abstract-full" style="display: none;"> Laser-induced gauge fields in neutral atoms serve as a means of mimicking the effects of a magnetic field, providing researchers with a platform to explore behaviors analogous to those observed in condensed matter systems under real magnetic fields. Here, we propose a method to generate chiral motion in atomic excitations within the neutral atomic ground-state manifolds. This is achieved through the application of polychromatic driving fields coupled to the ground-Rydberg transition, along with unconventional Rydberg pumping. The scheme offers the advantage of arbitrary adjustment of the effective magnetic flux by setting the relative phases between different external laser fields. Additionally, the effective interaction strength between the atomic ground states can be maintained at 10 kHz, surpassing the capabilities of the previous approach utilizing Floquet modulation. Notably, the proposed method can be readily extended to implement a hexagonal neutral atom lattice, serving as the fundamental unit in realizing the Haldane model. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.11291v2-abstract-full').style.display = 'none'; document.getElementById('2406.11291v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 17 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">Some typographical errors in the timeline of Fig.5(c), Eq.(14), and Eq.(A1) of the published version have been corrected</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> APL Quantum 1, 036109 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2406.08948">arXiv:2406.08948</a> <span> [<a href="https://arxiv.org/pdf/2406.08948">pdf</a>, <a href="https://arxiv.org/format/2406.08948">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="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"> Validity of the Lieb-Schultz-Mattis Theorem in Long-Range Interacting Systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Y">Yi-Neng Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xingyu 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="2406.08948v2-abstract-short" style="display: inline;"> The Lieb-Schultz-Mattis (LSM) theorem asserts that microscopic details of the system can impose non-trivial constraints on the system's low-energy properties. While traditionally applied to short-range interaction systems, where locality ensures a vanishing spectral gap in large system size limit, the impact of long-range interactions on the LSM theorem remains an open question. Long-range interac… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.08948v2-abstract-full').style.display = 'inline'; document.getElementById('2406.08948v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2406.08948v2-abstract-full" style="display: none;"> The Lieb-Schultz-Mattis (LSM) theorem asserts that microscopic details of the system can impose non-trivial constraints on the system's low-energy properties. While traditionally applied to short-range interaction systems, where locality ensures a vanishing spectral gap in large system size limit, the impact of long-range interactions on the LSM theorem remains an open question. Long-range interactions are prevalent in experimental platforms such as Rydberg atoms, dipolar quantum gases, polar molecules, optical cavities, and trapped ions, where the interaction decay exponent can be experimentally tuned. We extend the LSM theorem in one dimension to long-range interacting systems and find that the LSM theorem holds for exponentially or power-law two-body interactions with a decay exponent $伪> 2$. However, for power-law interactions with $伪< 2$, the constraints of the LSM theorem on the ground state do not apply. Numerical simulations of long-range versions of the Heisenberg and Majumdar-Ghosh models, both satisfying the LSM symmetry requirements, are also provided. Our results suggest promising directions for experimental validation of the LSM theorem in systems with tunable long-range interactions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.08948v2-abstract-full').style.display = 'none'; document.getElementById('2406.08948v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 13 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">5 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/2406.07055">arXiv:2406.07055</a> <span> [<a href="https://arxiv.org/pdf/2406.07055">pdf</a>, <a href="https://arxiv.org/format/2406.07055">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"> Adaptive quantum optimization algorithms for programmable atom-cavity systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Luo%2C+Y">Yuchen Luo</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xiaopeng Li</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+J">Jian Lin</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2406.07055v1-abstract-short" style="display: inline;"> Developing quantum algorithms adaptive to specific constraints of near-term devices is an essential step towards practical quantum advantage. In a recent work [Phys. Rev. Lett. 131, 103601(2023)], we show cold atoms in an optical cavity can be built as a universal quantum optimizer with programmable all-to-all interactions, and the effective Hamiltonian for atoms directly encodes number partitioni… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.07055v1-abstract-full').style.display = 'inline'; document.getElementById('2406.07055v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2406.07055v1-abstract-full" style="display: none;"> Developing quantum algorithms adaptive to specific constraints of near-term devices is an essential step towards practical quantum advantage. In a recent work [Phys. Rev. Lett. 131, 103601(2023)], we show cold atoms in an optical cavity can be built as a universal quantum optimizer with programmable all-to-all interactions, and the effective Hamiltonian for atoms directly encodes number partitioning problems (NPPs). Here, we numerically investigate the performance of quantum annealing (QA) and quantum approximate optimization algorithm (QAOA) to find the solution of NPP that is encoded in the ground state of atomic qubits. We find the success probability of the standard QA decays rapidly with the problem size. The optimized annealing path or inhomogeneous driving fields only lead to mild improvement on the success probability. Similarly, the standard QAOA always gets trapped in a false local minimum, and there is no significant performance improvement as we increase the depth of the quantum circuit. Inspired by the counterdiabatic driving, we propose an adaptive ansatz of QAOA which releases the parameter freedom of the NPP Hamiltonian to match higher-order counterdiabatic terms. Through numerical simulations, we find that our adaptive QAOA can achieve the optimal solution within very small circuit depth. It is thus worth paying the extra optimization cost of additional parameters for improving QAOA performance. Therefore, our adaptive QAOA provides a promising choice for programmable atom-cavity systems to demonstrate competitive computational power within its quantum coherence time. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.07055v1-abstract-full').style.display = 'none'; document.getElementById('2406.07055v1-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> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2406.03867">arXiv:2406.03867</a> <span> [<a href="https://arxiv.org/pdf/2406.03867">pdf</a>, <a href="https://arxiv.org/format/2406.03867">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="Emerging Technologies">cs.ET</span> </div> </div> <p class="title is-5 mathjax"> A Comprehensive Study of Quantum Arithmetic Circuits </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wang%2C+S">Siyi Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xiufan Li</a>, <a href="/search/quant-ph?searchtype=author&query=Lee%2C+W+J+B">Wei Jie Bryan Lee</a>, <a href="/search/quant-ph?searchtype=author&query=Deb%2C+S">Suman Deb</a>, <a href="/search/quant-ph?searchtype=author&query=Lim%2C+E">Eugene Lim</a>, <a href="/search/quant-ph?searchtype=author&query=Chattopadhyay%2C+A">Anupam Chattopadhyay</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="2406.03867v1-abstract-short" style="display: inline;"> In recent decades, the field of quantum computing has experienced remarkable progress. This progress is marked by the superior performance of many quantum algorithms compared to their classical counterparts, with Shor's algorithm serving as a prominent illustration. Quantum arithmetic circuits, which are the fundamental building blocks in numerous quantum algorithms, have attracted much attention.… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.03867v1-abstract-full').style.display = 'inline'; document.getElementById('2406.03867v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2406.03867v1-abstract-full" style="display: none;"> In recent decades, the field of quantum computing has experienced remarkable progress. This progress is marked by the superior performance of many quantum algorithms compared to their classical counterparts, with Shor's algorithm serving as a prominent illustration. Quantum arithmetic circuits, which are the fundamental building blocks in numerous quantum algorithms, have attracted much attention. Despite extensive exploration of various designs in the existing literature, researchers remain keen on developing novel designs and improving existing ones. In this review article, we aim to provide a systematically organized and easily comprehensible overview of the current state-of-the-art in quantum arithmetic circuits. Specifically, this study covers fundamental operations such as addition, subtraction, multiplication, division and modular exponentiation. We delve into the detailed quantum implementations of these prominent designs and evaluate their efficiency considering various objectives. We also discuss potential applications of presented arithmetic circuits and suggest future research directions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.03867v1-abstract-full').style.display = 'none'; document.getElementById('2406.03867v1-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 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">Under review at the Royal Society's Philosophical Transactions A</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2406.03081">arXiv:2406.03081</a> <span> [<a href="https://arxiv.org/pdf/2406.03081">pdf</a>, <a href="https://arxiv.org/format/2406.03081">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> A Quantum Neural Network-Based Approach to Power Quality Disturbances Detection and Recognition </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+G">Guo-Dong Li</a>, <a href="/search/quant-ph?searchtype=author&query=He%2C+H">Hai-Yan He</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yue Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xin-Hao Li</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+H">Hao Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Q">Qing-Le Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Cheng%2C+L">Long Cheng</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="2406.03081v1-abstract-short" style="display: inline;"> Power quality disturbances (PQDs) significantly impact the stability and reliability of power systems, necessitating accurate and efficient detection and recognition methods. While numerous classical algorithms for PQDs detection and recognition have been extensively studied and applied, related work in the quantum domain is still in its infancy. In this paper, an improved quantum neural networks… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.03081v1-abstract-full').style.display = 'inline'; document.getElementById('2406.03081v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2406.03081v1-abstract-full" style="display: none;"> Power quality disturbances (PQDs) significantly impact the stability and reliability of power systems, necessitating accurate and efficient detection and recognition methods. While numerous classical algorithms for PQDs detection and recognition have been extensively studied and applied, related work in the quantum domain is still in its infancy. In this paper, an improved quantum neural networks (QNN) model for PQDs detection and recognition is proposed. Specifically, the model constructs a quantum circuit comprising data qubits and ancilla qubits. Classical data is transformed into quantum data by embedding it into data qubits via the encoding layer. Subsequently, parametric quantum gates are utilized to form the variational layer, which facilitates qubit information transformation, thereby extracting essential feature information for detection and recognition. The expected value is obtained by measuring ancilla qubits, enabling the completion of disturbance classification based on this expected value. An analysis reveals that the runtime and space complexities of the QNN are $O\left ( poly\left ( N \right ) \right )$ and $O\left ( N \right )$, respectively. Extensive experiments validate the feasibility and superiority of the proposed model in PQD detection and recognition. The model achieves accuracies of 99.75\%, 97.85\% and 95.5\% in experiments involving the detection of disturbances, recognition of seven single disturbances, and recognition of ten mixed disturbances, respectively. Additionally, noise simulation and comparative experiments demonstrate that the proposed model exhibits robust anti-noise capabilities, requires few training parameters, and maintains high accuracy. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.03081v1-abstract-full').style.display = 'none'; document.getElementById('2406.03081v1-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 June, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2405.20659">arXiv:2405.20659</a> <span> [<a href="https://arxiv.org/pdf/2405.20659">pdf</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="Applied Physics">physics.app-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Popular Physics">physics.pop-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"> Realization of cold atom gyroscope in space </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+J">Jinting Li</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+X">Xi Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+D">Danfang Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+W">Wenzhang Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Y">Yang Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=He%2C+M">Meng He</a>, <a href="/search/quant-ph?searchtype=author&query=Fang%2C+J">Jie Fang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+L">Lin Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=He%2C+C">Chuan He</a>, <a href="/search/quant-ph?searchtype=author&query=Jiang%2C+J">Junjie Jiang</a>, <a href="/search/quant-ph?searchtype=author&query=Sun%2C+H">Huanyao Sun</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Q">Qunfeng Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Qin%2C+L">Lei Qin</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xiao Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Y">Yibo Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+X">Xiaowei Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhong%2C+J">Jiaqi Zhong</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+R">Runbing Li</a>, <a href="/search/quant-ph?searchtype=author&query=An%2C+M">Meizhen An</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+L">Long Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+S">Shuquan Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zongfeng Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+J">Jin Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhan%2C+M">Mingsheng Zhan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2405.20659v2-abstract-short" style="display: inline;"> High-precision gyroscopes in space are essential for fundamental physics research and navigation. Due to its potential high precision, the cold atom gyroscope is expected to be the next generation of gyroscopes in space. Here, we report the first realization of a cold atom gyroscope, which was demonstrated by the atom interferometer installed in the China Space Station (CSS) as a payload. By compe… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.20659v2-abstract-full').style.display = 'inline'; document.getElementById('2405.20659v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.20659v2-abstract-full" style="display: none;"> High-precision gyroscopes in space are essential for fundamental physics research and navigation. Due to its potential high precision, the cold atom gyroscope is expected to be the next generation of gyroscopes in space. Here, we report the first realization of a cold atom gyroscope, which was demonstrated by the atom interferometer installed in the China Space Station (CSS) as a payload. By compensating for CSS's high dynamic rotation rate using a built-in piezoelectric mirror, spatial interference fringes in the interferometer are successfully obtained. Then, the optimized ratio of the Raman laser's angles is derived, the coefficients of the piezoelectric mirror are self-calibrated in orbit, and various systemic effects are corrected. We achieve a rotation measurement resolution of 50*10^-6 rad/s for a single shot and 17*10^-6 rad/s for an average number of 32. The measured rotation is (-1142+/-29)*10^-6 rad/s and is compatible with that recorded by the classical gyroscope of the CSS. This study paves the way for developing high-precision cold atom gyroscopes in space. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.20659v2-abstract-full').style.display = 'none'; document.getElementById('2405.20659v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 31 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">14 pages, 3 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2405.20295">arXiv:2405.20295</a> <span> [<a href="https://arxiv.org/pdf/2405.20295">pdf</a>, <a href="https://arxiv.org/format/2405.20295">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"> How (not) to Build Quantum PKE in Minicrypt </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+L">Longcheng Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Q">Qian Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xingjian Li</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+Q">Qipeng Liu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2405.20295v1-abstract-short" style="display: inline;"> The seminal work by Impagliazzo and Rudich (STOC'89) demonstrated the impossibility of constructing classical public key encryption (PKE) from one-way functions (OWF) in a black-box manner. However, the question remains: can quantum PKE (QPKE) be constructed from quantumly secure OWF? A recent line of work has shown that it is indeed possible to build QPKE from OWF, but with one caveat -- they rel… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.20295v1-abstract-full').style.display = 'inline'; document.getElementById('2405.20295v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.20295v1-abstract-full" style="display: none;"> The seminal work by Impagliazzo and Rudich (STOC'89) demonstrated the impossibility of constructing classical public key encryption (PKE) from one-way functions (OWF) in a black-box manner. However, the question remains: can quantum PKE (QPKE) be constructed from quantumly secure OWF? A recent line of work has shown that it is indeed possible to build QPKE from OWF, but with one caveat -- they rely on quantum public keys, which cannot be authenticated and reused. In this work, we re-examine the possibility of perfect complete QPKE in the quantum random oracle model (QROM), where OWF exists. Our first main result: QPKE with classical public keys, secret keys and ciphertext, does not exist in the QROM, if the key generation only makes classical queries. Therefore, a necessary condition for constructing such QPKE from OWF is to have the key generation classically ``un-simulatable''. Previous discussions (Austrin et al. CRYPTO'22) on the impossibility of QPKE from OWF rely on a seemingly strong conjecture. Our work makes a significant step towards a complete and unconditional quantization of Impagliazzo and Rudich's results. Our second main result extends to QPKE with quantum public keys. The second main result: QPKE with quantum public keys, classical secret keys and ciphertext, does not exist in the QROM, if the key generation only makes classical queries and the quantum public key is either pure or ``efficiently clonable''. The result is tight due to all existing QPKEs constructions. Our result further gives evidence on why existing QPKEs lose reusability. To achieve these results, we use a novel argument based on conditional mutual information and quantum Markov chain by Fawzi and Renner (Communications in Mathematical Physics). We believe the techniques used in the work will find other usefulness in separations in quantum cryptography/complexity. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.20295v1-abstract-full').style.display = 'none'; document.getElementById('2405.20295v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2405.19245">arXiv:2405.19245</a> <span> [<a href="https://arxiv.org/pdf/2405.19245">pdf</a>, <a href="https://arxiv.org/ps/2405.19245">ps</a>, <a href="https://arxiv.org/format/2405.19245">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="Optimization and Control">math.OC</span> </div> </div> <p class="title is-5 mathjax"> Efficient Optimal Control of Open Quantum Systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=He%2C+W">Wenhao He</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+T">Tongyang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xiantao Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zecheng Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+C">Chunhao Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+K">Ke Wang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2405.19245v1-abstract-short" style="display: inline;"> The optimal control problem for open quantum systems can be formulated as a time-dependent Lindbladian that is parameterized by a number of time-dependent control variables. Given an observable and an initial state, the goal is to tune the control variables so that the expected value of some observable with respect to the final state is maximized. In this paper, we present algorithms for solving t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.19245v1-abstract-full').style.display = 'inline'; document.getElementById('2405.19245v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.19245v1-abstract-full" style="display: none;"> The optimal control problem for open quantum systems can be formulated as a time-dependent Lindbladian that is parameterized by a number of time-dependent control variables. Given an observable and an initial state, the goal is to tune the control variables so that the expected value of some observable with respect to the final state is maximized. In this paper, we present algorithms for solving this optimal control problem efficiently, i.e., having a poly-logarithmic dependency on the system dimension, which is exponentially faster than best-known classical algorithms. Our algorithms are hybrid, consisting of both quantum and classical components. The quantum procedure simulates time-dependent Lindblad evolution that drives the initial state to the final state, and it also provides access to the gradients of the objective function via quantum gradient estimation. The classical procedure uses the gradient information to update the control variables. At the technical level, we provide the first (to the best of our knowledge) simulation algorithm for time-dependent Lindbladians with an $\ell_1$-norm dependence. As an alternative, we also present a simulation algorithm in the interaction picture to improve the algorithm for the cases where the time-independent component of a Lindbladian dominates the time-dependent part. On the classical side, we heavily adapt the state-of-the-art classical optimization analysis to interface with the quantum part of our algorithms. Both the quantum simulation techniques and the classical optimization analyses might be of independent interest. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.19245v1-abstract-full').style.display = 'none'; document.getElementById('2405.19245v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 29 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">52 pages. To appear in the proceedings of TQC 2024</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2405.17736">arXiv:2405.17736</a> <span> [<a href="https://arxiv.org/pdf/2405.17736">pdf</a>, <a href="https://arxiv.org/format/2405.17736">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"> Phonon Number Measurement Using Optimal Composite Pulses </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xie-Qian Li</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+P">Ping-Xing 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="2405.17736v1-abstract-short" style="display: inline;"> Measuring the phonon number of the laser-cooled ions is an indispensable step in evaluating whether an ion is in ground state. At present, commonly used methods in the experiments are red-to-blue sideband ratios and adiabatic evolution red-sideband methods. We theoretically propose a method using composite pulses which does not need a fit of state evolution and can directly measure the population… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.17736v1-abstract-full').style.display = 'inline'; document.getElementById('2405.17736v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.17736v1-abstract-full" style="display: none;"> Measuring the phonon number of the laser-cooled ions is an indispensable step in evaluating whether an ion is in ground state. At present, commonly used methods in the experiments are red-to-blue sideband ratios and adiabatic evolution red-sideband methods. We theoretically propose a method using composite pulses which does not need a fit of state evolution and can directly measure the population of the selected Fock state. It can measure higher Fock state population more directly comparing with the adiabatic evolution red-sideband method. We use quantum optimal control method to improve the fidelity of unitary operation of the composite pulses. With quantum optimal control technology, we can discuss the situation where the laser strength is strong, and many approximations will not be necessary, where the gate fidelity can be further improved. Then we give a method to modify the measurement result for a higher accuracy which has a good performance, and we give an example to illustrate its application on high Fock state measurement. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.17736v1-abstract-full').style.display = 'none'; document.getElementById('2405.17736v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2024. </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=Li%2C+X&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a 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