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is-link">Go</button> </div> </div> </form> </div> </div> <nav class="pagination is-small is-centered breathe-horizontal" role="navigation" aria-label="pagination"> <a href="" class="pagination-previous is-invisible">Previous </a> <a href="/search/?searchtype=author&query=Li%2C+Z&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Li%2C+Z&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=Li%2C+Z&start=50" class="pagination-link " aria-label="Page 2" aria-current="page">2 </a> </li> <li> <a href="/search/?searchtype=author&query=Li%2C+Z&start=100" class="pagination-link " aria-label="Page 3" aria-current="page">3 </a> </li> <li> <a href="/search/?searchtype=author&query=Li%2C+Z&start=150" class="pagination-link " aria-label="Page 4" aria-current="page">4 </a> </li> <li> <a href="/search/?searchtype=author&query=Li%2C+Z&start=200" 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/2502.17725">arXiv:2502.17725</a> <span> [<a href="https://arxiv.org/pdf/2502.17725">pdf</a>, <a href="https://arxiv.org/format/2502.17725">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Artificial Intelligence">cs.AI</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mathematical Physics">math-ph</span> </div> </div> <p class="title is-5 mathjax"> Solving the Traveling Salesman Problem via Different Quantum Computing Architectures </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Padmasola%2C+V">Venkat Padmasola</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zhaotong Li</a>, <a href="/search/quant-ph?searchtype=author&query=Chatterjee%2C+R">Rupak Chatterjee</a>, <a href="/search/quant-ph?searchtype=author&query=Dyk%2C+W">Wesley Dyk</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2502.17725v1-abstract-short" style="display: inline;"> We study the application of emerging photonic and quantum computing architectures to solving the Traveling Salesman Problem (TSP), a well-known NP-hard optimization problem. We investigate several approaches: Simulated Annealing (SA), Quadratic Unconstrained Binary Optimization (QUBO-Ising) methods implemented on quantum annealers and Optical Coherent Ising Machines, as well as the Quantum Approxi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.17725v1-abstract-full').style.display = 'inline'; document.getElementById('2502.17725v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2502.17725v1-abstract-full" style="display: none;"> We study the application of emerging photonic and quantum computing architectures to solving the Traveling Salesman Problem (TSP), a well-known NP-hard optimization problem. We investigate several approaches: Simulated Annealing (SA), Quadratic Unconstrained Binary Optimization (QUBO-Ising) methods implemented on quantum annealers and Optical Coherent Ising Machines, as well as the Quantum Approximate Optimization Algorithm (QAOA) and the Quantum Phase Estimation (QPE) algorithm on gate-based quantum computers. QAOA and QPE were tested on the IBM Quantum platform. The QUBO-Ising method was explored using the D-Wave quantum annealer, which operates on superconducting Josephson junctions, and the QCI Dirac machine, a nonlinear optoelectronic Ising machine. Gate-based quantum computers demonstrated accurate results for small TSP instances in simulation. However, real quantum devices are hindered by noise and limited scalability. Circuit complexity grows with problem size, restricting performance to TSP instances with a maximum of 6 nodes. In contrast, Ising-based architectures show improved scalability for larger problem sizes. SQUID-based Ising machines can handle TSP instances with up to 12 nodes, while nonlinear optoelectronic Ising machines extend this capability to 18 nodes. Nevertheless, the solutions tend to be suboptimal due to hardware limitations and challenges in achieving ground state convergence as the problem size increases. Despite these limitations, Ising machines demonstrate significant time advantages over classical methods, making them a promising candidate for solving larger-scale TSPs efficiently. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.17725v1-abstract-full').style.display = 'none'; document.getElementById('2502.17725v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 24 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2025. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, 21 figures, 32 citations</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">ACM Class:</span> F.2.2 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2502.15386">arXiv:2502.15386</a> <span> [<a href="https://arxiv.org/pdf/2502.15386">pdf</a>, <a href="https://arxiv.org/format/2502.15386">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Emerging Technologies">cs.ET</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"> EDA-Q: Electronic Design Automation for Superconducting Quantum Chip </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+B">Bo Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zhihang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Yu%2C+X">Xiaohan Yu</a>, <a href="/search/quant-ph?searchtype=author&query=Yuan%2C+B">Benzheng Yuan</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+C">Chaojie Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Gao%2C+Y">Yimin Gao</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+W">Weilong Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Mu%2C+Q">Qing Mu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+S">Shuya Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Sun%2C+H">Huihui Sun</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+T">Tian Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+M">Mengfan Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Han%2C+C">Chuanbing Han</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+P">Peng Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+W">Wenqing Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Shan%2C+Z">Zheng Shan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2502.15386v2-abstract-short" style="display: inline;"> Electronic Design Automation (EDA) plays a crucial role in classical chip design and significantly influences the development of quantum chip design. However, traditional EDA tools cannot be directly applied to quantum chip design due to vast differences compared to the classical realm. Several EDA products tailored for quantum chip design currently exist, yet they only cover partial stages of the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.15386v2-abstract-full').style.display = 'inline'; document.getElementById('2502.15386v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2502.15386v2-abstract-full" style="display: none;"> Electronic Design Automation (EDA) plays a crucial role in classical chip design and significantly influences the development of quantum chip design. However, traditional EDA tools cannot be directly applied to quantum chip design due to vast differences compared to the classical realm. Several EDA products tailored for quantum chip design currently exist, yet they only cover partial stages of the quantum chip design process instead of offering a fully comprehensive solution. Additionally, they often encounter issues such as limited automation, steep learning curves, challenges in integrating with actual fabrication processes, and difficulties in expanding functionality. To address these issues, we developed a full-stack EDA tool specifically for quantum chip design, called EDA-Q. The design workflow incorporates functionalities present in existing quantum EDA tools while supplementing critical design stages such as device mapping and fabrication process mapping, which users expect. EDA-Q utilizes a unique architecture to achieve exceptional scalability and flexibility. The integrated design mode guarantees algorithm compatibility with different chip components, while employing a specialized interactive processing mode to offer users a straightforward and adaptable command interface. Application examples demonstrate that EDA-Q significantly reduces chip design cycles, enhances automation levels, and decreases the time required for manual intervention. Multiple rounds of testing on the designed chip have validated the effectiveness of EDA-Q in practical applications. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.15386v2-abstract-full').style.display = 'none'; document.getElementById('2502.15386v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 24 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 21 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2025. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">12pages, 11 figures, 4 tables</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2502.11412">arXiv:2502.11412</a> <span> [<a href="https://arxiv.org/pdf/2502.11412">pdf</a>, <a href="https://arxiv.org/format/2502.11412">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 decision trees with information entropy </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zhelun Li</a>, <a href="/search/quant-ph?searchtype=author&query=Terashi%2C+K">Koji Terashi</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2502.11412v3-abstract-short" style="display: inline;"> We present a classification algorithm for quantum states, inspired by decision-tree methods. To adapt the decision-tree framework to the probabilistic nature of quantum measurements, we utilize conditional probabilities to compute information gain, thereby optimizing the measurement scheme. For each measurement shot on an unknown quantum state, the algorithm selects the observable with the highest… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.11412v3-abstract-full').style.display = 'inline'; document.getElementById('2502.11412v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2502.11412v3-abstract-full" style="display: none;"> We present a classification algorithm for quantum states, inspired by decision-tree methods. To adapt the decision-tree framework to the probabilistic nature of quantum measurements, we utilize conditional probabilities to compute information gain, thereby optimizing the measurement scheme. For each measurement shot on an unknown quantum state, the algorithm selects the observable with the highest expected information gain, continuing until convergence. We demonstrate using the simulations that this algorithm effectively identifies quantum states sampled from the Haar random distribution. However, despite not relying on circuit-based quantum neural networks, the algorithm still encounters challenges akin to the barren plateau problem. In the leading order, we show that the information gain is proportional to the variance of the observable's expectation values over candidate states. As the system size increases, this variance, and consequently the information gain, are exponentially suppressed, which poses significant challenges for classifying general Haar-random quantum states. Finally, we apply the quantum decision tree to classify the ground states of various Hamiltonians using physically-motivated observables. On both simulators and quantum computers, the quantum decision tree yields better performances when compared to methods that are not information-optimized. This indicates that the measurement of physically-motivated observables can significantly improve the classification performance, guiding towards the future direction of this approach. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.11412v3-abstract-full').style.display = 'none'; document.getElementById('2502.11412v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 24 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 16 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2025. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Addressing some minor comments</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2502.11365">arXiv:2502.11365</a> <span> [<a href="https://arxiv.org/pdf/2502.11365">pdf</a>, <a href="https://arxiv.org/format/2502.11365">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"> Machine Learning for Detecting Steering in Qutrit-Pair States </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wang%2C+P">Pu Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zhongyan Li</a>, <a href="/search/quant-ph?searchtype=author&query=Meng%2C+H">Huixian Meng</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2502.11365v3-abstract-short" style="display: inline;"> Only a few states in high-dimensional systems can be identified as (un)steerable using existing theoretical or experimental methods. We utilize semidefinite programming (SDP) to construct a dataset for steerability detection in qutrit-qutrit systems. For the full-information feature $F_1$, artificial neural networks achieve high classification accuracy and generalization, and preform better than t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.11365v3-abstract-full').style.display = 'inline'; document.getElementById('2502.11365v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2502.11365v3-abstract-full" style="display: none;"> Only a few states in high-dimensional systems can be identified as (un)steerable using existing theoretical or experimental methods. We utilize semidefinite programming (SDP) to construct a dataset for steerability detection in qutrit-qutrit systems. For the full-information feature $F_1$, artificial neural networks achieve high classification accuracy and generalization, and preform better than the support vector machine. As feature engineering playing a pivotal role, we introduce a steering ellipsoid-like feature $F_2$, which significantly enhances the performance of each of our models. Given the SDP method provides only a sufficient condition for steerability detection, we establish the first rigorously constructed, accurately labeled dataset based on theoretical foundations. This dataset enables models to exhibit outstanding accuracy and generalization capabilities, independent of the choice of features. As applications, we investigate the steerability boundaries of isotropic states and partially entangled states, and find new steerable states. This work not only advances the application of machine learning for probing quantum steerability in high-dimensional systems but also deepens the theoretical understanding of quantum steerability itself. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.11365v3-abstract-full').style.display = 'none'; document.getElementById('2502.11365v3-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 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 16 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2025. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2502.07536">arXiv:2502.07536</a> <span> [<a href="https://arxiv.org/pdf/2502.07536">pdf</a>, <a href="https://arxiv.org/format/2502.07536">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"> HAIL: An Efficient Iterative Algorithm for Qubit Mapping via Layer-Weight Assignment and Search Space Reduction </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Xu%2C+K">Kang Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zeyang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+X">Xinjian Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+D">Dandan Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Y">Yukun Wang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2502.07536v1-abstract-short" style="display: inline;"> Current quantum devices only support interactions between physical qubits and a limited number of neighboring qubits, preventing quantum circuits from being executed directly on the devices. To execute the circuit, SWAP gates must be inserted to adjust the mapping relationships between qubits, which consequently increases runtime and error rates in quantum circuits. To address these challenges, th… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.07536v1-abstract-full').style.display = 'inline'; document.getElementById('2502.07536v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2502.07536v1-abstract-full" style="display: none;"> Current quantum devices only support interactions between physical qubits and a limited number of neighboring qubits, preventing quantum circuits from being executed directly on the devices. To execute the circuit, SWAP gates must be inserted to adjust the mapping relationships between qubits, which consequently increases runtime and error rates in quantum circuits. To address these challenges, this paper proposes HAIL, an efficient iterative qubit mapping algorithm to minimize additional SWAP gates. First, a layer-weight assignment method integrated with the subgraph isomorphism algorithm is introduced to establish an initial mapping. Next, we propose a SWAP sequence search combined with the post-processing function to identify the optimal SWAP sequences. Finally, the qubit mapping algorithm is refined through iterative forward and backward traversals to further reduce the number of SWAP gates. Experimental results on the IBM Q20 architecture and various benchmarks demonstrate that HAIL-3 reduces the number of additional gates inserted in the $\mathcal{B}_{23}$ by 20.62% compared to state-of-the-art algorithms. Additionally, we present a partially extended strategy based on HAIL to reduce the sequence search space, with experiments on the sparsely connected Google Sycamore architecture showing a reduction in both algorithm runtime and additional SWAP gates. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.07536v1-abstract-full').style.display = 'none'; document.getElementById('2502.07536v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2025. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2502.04100">arXiv:2502.04100</a> <span> [<a href="https://arxiv.org/pdf/2502.04100">pdf</a>, <a href="https://arxiv.org/format/2502.04100">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"> DAPO-QAOA: An algorithm for solving combinatorial optimization problems by dynamically constructing phase operators </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Y">Yukun Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">ZeYang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wan%2C+L">Linchun Wan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2502.04100v1-abstract-short" style="display: inline;"> The Quantum Approximate Optimization Algorithm (QAOA) is a well-known hybrid quantum-classical algorithm for combinatorial optimization problems. Improving QAOA involves enhancing its approximation ratio while addressing practical constraints of Noisy Intermediate Scale Quantum (NISQ) devices, such as minimizing the number of two-qubit gates and reducing circuit depth. Although existing research h… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.04100v1-abstract-full').style.display = 'inline'; document.getElementById('2502.04100v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2502.04100v1-abstract-full" style="display: none;"> The Quantum Approximate Optimization Algorithm (QAOA) is a well-known hybrid quantum-classical algorithm for combinatorial optimization problems. Improving QAOA involves enhancing its approximation ratio while addressing practical constraints of Noisy Intermediate Scale Quantum (NISQ) devices, such as minimizing the number of two-qubit gates and reducing circuit depth. Although existing research has optimized designs for phase and mixer operators to improve performance, challenges remain, particularly concerning the excessive use of two-qubit gates in the construction of phase operators. To address these issues, we introduce a Dynamic Adaptive Phase Operator (DAPO) algorithm, which dynamically constructs phase operators based on the output of previous layers and neighborhood search approach, optimizing the problem Hamiltonian more efficiently. By using solutions generated by QAOA itself to simplify the problem Hamiltonian at each layer, the algorithm captures the problem's structural properties more effectively, progressively steering the solution closer to the optimal target. Experimental results on MaxCut and NAE3SAT problems show that DAPO achieves higher approximation ratios and significantly reduces two-qubit RZZ gates, especially in dense graphs. Compared to vanilla QAOA, DAPO uses only 66% of RZZ gates at the same depth while delivering better results, demonstrating its potential for efficient combinatorial optimization in the NISQ era. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.04100v1-abstract-full').style.display = 'none'; document.getElementById('2502.04100v1-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 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2025. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2501.15376">arXiv:2501.15376</a> <span> [<a href="https://arxiv.org/pdf/2501.15376">pdf</a>, <a href="https://arxiv.org/format/2501.15376">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="Networking and Internet Architecture">cs.NI</span> </div> </div> <p class="title is-5 mathjax"> QuESat: Satellite-Assisted Quantum Internet for Global-Scale Entanglement Distribution </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Gu%2C+H">Huayue Gu</a>, <a href="/search/quant-ph?searchtype=author&query=Yu%2C+R">Ruozhou Yu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zhouyu Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+X">Xiaojian Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Xue%2C+G">Guoliang 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="2501.15376v1-abstract-short" style="display: inline;"> Entanglement distribution across remote distances is critical for many quantum applications. Currently, the de facto approach for remote entanglement distribution relies on optical fiber for on-the-ground entanglement distribution. However, the fiber-based approach is incapable of global-scale entanglement distribution due to intrinsic limitations. This paper investigates a new hybrid ground-satel… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.15376v1-abstract-full').style.display = 'inline'; document.getElementById('2501.15376v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.15376v1-abstract-full" style="display: none;"> Entanglement distribution across remote distances is critical for many quantum applications. Currently, the de facto approach for remote entanglement distribution relies on optical fiber for on-the-ground entanglement distribution. However, the fiber-based approach is incapable of global-scale entanglement distribution due to intrinsic limitations. This paper investigates a new hybrid ground-satellite quantum network architecture (QuESat) for global-scale entanglement distribution, integrating an on-the-ground fiber network with a global-scale passive optical network built with low-Earth-orbit satellites. The satellite network provides dynamic construction of photon lightpaths based on near-vacuum beam guides constructed via adjustable arrays of lenses, forwarding photons from one ground station to another with very high efficiency over long distances compared to using fiber. To assess the feasibility and effectiveness of QuESat for global communication, we formulate lightpath provisioning and entanglement distribution problems, considering the orbital dynamics of satellites and the time-varying entanglement demands from ground users. A two-stage algorithm is developed to dynamically configure the beam guides and distribute entanglements, respectively. The algorithm combines randomized and deterministic rounding for lightpath provisioning to enable global connectivity, with optimal entanglement swapping for distributing entanglements to meet users' demands. By developing a ground-satellite quantum network simulator, QuESat achieves multi-fold improvements compared to repeater networks. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.15376v1-abstract-full').style.display = 'none'; document.getElementById('2501.15376v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 25 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2501.13459">arXiv:2501.13459</a> <span> [<a href="https://arxiv.org/pdf/2501.13459">pdf</a>, <a href="https://arxiv.org/format/2501.13459">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Disordered Systems and Neural Networks">cond-mat.dis-nn</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Statistical Mechanics">cond-mat.stat-mech</span> </div> </div> <p class="title is-5 mathjax"> Symmetry Breaking Dynamics in Quantum Many-Body Systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Yu%2C+H">Hui Yu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zi-Xiang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+S">Shi-Xin 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="2501.13459v2-abstract-short" style="display: inline;"> Entanglement asymmetry has emerged as a powerful tool for characterizing symmetry breaking in quantum many-body systems. In this Letter, we explore how symmetry is dynamically broken through the lens of entanglement asymmetry in two distinct scenarios: a non-symmetric random quantum circuit and a non-symmetric Hamiltonian quench, with a particular focus on U(1) symmetry. In the former case, the sy… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.13459v2-abstract-full').style.display = 'inline'; document.getElementById('2501.13459v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.13459v2-abstract-full" style="display: none;"> Entanglement asymmetry has emerged as a powerful tool for characterizing symmetry breaking in quantum many-body systems. In this Letter, we explore how symmetry is dynamically broken through the lens of entanglement asymmetry in two distinct scenarios: a non-symmetric random quantum circuit and a non-symmetric Hamiltonian quench, with a particular focus on U(1) symmetry. In the former case, the symmetry is initially broken and subsequently restored, whereas in the latter case, symmetry remains broken in the subsystem at late times, consistent with the principles of quantum thermalization. Notably, the growth of entanglement asymmetry exhibits unexpected overshooting behavior at early times in both contexts, contrasting with the behavior of charge variance. We also consider dynamics of non-symmetric initial states under the symmetry-breaking evolution. Due to the competition of symmetry-breaking in both the initial state and Hamiltonian, the early-time entanglement asymmetry can increase and decrease, while quantum Mpemba effects remain evident despite the weak symmetry-breaking in both settings. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.13459v2-abstract-full').style.display = 'none'; document.getElementById('2501.13459v2-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 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 23 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">5 pages, 4 figures with supplemental materials</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2501.07866">arXiv:2501.07866</a> <span> [<a href="https://arxiv.org/pdf/2501.07866">pdf</a>, <a href="https://arxiv.org/format/2501.07866">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"> Multifractal-enriched mobility edges and emergent quantum phases in Rydberg atomic arrays </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shan-Zhong Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Y">Yi-Cai Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Y">Yucheng Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+S">Shanchao Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+S">Shi-Liang Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zhi 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="2501.07866v2-abstract-short" style="display: inline;"> Anderson localization describes disorder-induced phase transitions, distinguishing between localized and extended states. In quasiperiodic systems, a third multifractal state emerges, characterized by unique energy and wave functions. However, critical indicators for differentiating these states, such as Lyapunov exponents (LEs) and inverse participation ratios (IPRs), have yet to be experimentall… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.07866v2-abstract-full').style.display = 'inline'; document.getElementById('2501.07866v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.07866v2-abstract-full" style="display: none;"> Anderson localization describes disorder-induced phase transitions, distinguishing between localized and extended states. In quasiperiodic systems, a third multifractal state emerges, characterized by unique energy and wave functions. However, critical indicators for differentiating these states, such as Lyapunov exponents (LEs) and inverse participation ratios (IPRs), have yet to be experimentally detected. To address these challenges, we introduce exactly solvable one-dimensional quasiperiodic lattice models with flat bands, analytically determining phase boundaries using Avila's global theorem. We propose experimental realizations using Rydberg atom arrays, enabling the distinction of localized, extended, and multifractal states with as few as 18 qubits. Importantly, we develop a robust spectroscopic method for the experimental measurement of LEs and IPRs. Our work opens new avenues for the experimental exploration of Anderson localization and multifractal states in artificial quantum systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.07866v2-abstract-full').style.display = 'none'; document.getElementById('2501.07866v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 23 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 14 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">5+22 pages, 4+16 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2501.06882">arXiv:2501.06882</a> <span> [<a href="https://arxiv.org/pdf/2501.06882">pdf</a>, <a href="https://arxiv.org/format/2501.06882">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> </div> </div> <p class="title is-5 mathjax"> A Flux-Tunable cavity for Dark matter detection </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+F">Fang Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Ziqian Li</a>, <a href="/search/quant-ph?searchtype=author&query=Dixit%2C+A+V">Akash V. Dixit</a>, <a href="/search/quant-ph?searchtype=author&query=Roy%2C+T">Tanay Roy</a>, <a href="/search/quant-ph?searchtype=author&query=Vrajitoarea%2C+A">Andrei Vrajitoarea</a>, <a href="/search/quant-ph?searchtype=author&query=Banerjee%2C+R">Riju Banerjee</a>, <a href="/search/quant-ph?searchtype=author&query=Anferov%2C+A">Alexander Anferov</a>, <a href="/search/quant-ph?searchtype=author&query=Lee%2C+K">Kan-Heng Lee</a>, <a href="/search/quant-ph?searchtype=author&query=Schuster%2C+D+I">David I. Schuster</a>, <a href="/search/quant-ph?searchtype=author&query=Chou%2C+A">Aaron Chou</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2501.06882v1-abstract-short" style="display: inline;"> Developing a dark matter detector with wide mass tunability is an immensely desirable property, yet it is challenging due to maintaining strong sensitivity. Resonant cavities for dark matter detection have traditionally employed mechanical tuning, moving parts around to change electromagnetic boundary conditions. However, these cavities have proven challenging to operate in sub-Kelvin cryogenic en… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.06882v1-abstract-full').style.display = 'inline'; document.getElementById('2501.06882v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.06882v1-abstract-full" style="display: none;"> Developing a dark matter detector with wide mass tunability is an immensely desirable property, yet it is challenging due to maintaining strong sensitivity. Resonant cavities for dark matter detection have traditionally employed mechanical tuning, moving parts around to change electromagnetic boundary conditions. However, these cavities have proven challenging to operate in sub-Kelvin cryogenic environments due to differential thermal contraction, low heat capacities, and low thermal conductivities. Instead, we develop an electronically tunable cavity architecture by coupling a superconducting 3D microwave cavity with a DC flux tunable SQUID. With a flux delivery system engineered to maintain high coherence in the cavity, we perform a hidden-photon dark matter search below the quantum-limited threshold. A microwave photon counting technique is employed through repeated quantum non-demolition measurements using a transmon qubit. With this device, we perform a hidden-photon search with a dark count rate of around 64 counts/s and constrain the kinetic mixing angle to ${\varepsilon}< 4\times 10^{-13}$ in a tunable band from 5.672 GHz to 5.694 GHz. By coupling multimode tunable cavities to the transmon, wider hidden-photon searching ranges are possible. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.06882v1-abstract-full').style.display = 'none'; document.getElementById('2501.06882v1-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 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2501.04921">arXiv:2501.04921</a> <span> [<a href="https://arxiv.org/pdf/2501.04921">pdf</a>, <a href="https://arxiv.org/format/2501.04921">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Entanglement-Assisted Concatenated Quantum Codes: Parameters and Asymptotic Performance </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Fan%2C+J">Jihao Fan</a>, <a href="/search/quant-ph?searchtype=author&query=Cheng%2C+W">Wei Cheng</a>, <a href="/search/quant-ph?searchtype=author&query=Luo%2C+G">Gaojun Luo</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zhou Li</a>, <a href="/search/quant-ph?searchtype=author&query=Cao%2C+M">Meng Cao</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2501.04921v1-abstract-short" style="display: inline;"> Entanglement-assisted concatenated quantum codes (EACQCs) are constructed by concatenating two entanglement-assisted quantum error-correcting codes (EAQECCs). By selecting the inner and outer component codes carefully, it is able to construct state-of-the-art EACQCs with parameters better than previous quantum codes. In this work, we use almost maximum-distance-separable (MDS) codes and $\hbar$-MD… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.04921v1-abstract-full').style.display = 'inline'; document.getElementById('2501.04921v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.04921v1-abstract-full" style="display: none;"> Entanglement-assisted concatenated quantum codes (EACQCs) are constructed by concatenating two entanglement-assisted quantum error-correcting codes (EAQECCs). By selecting the inner and outer component codes carefully, it is able to construct state-of-the-art EACQCs with parameters better than previous quantum codes. In this work, we use almost maximum-distance-separable (MDS) codes and $\hbar$-MDS codes as the outer codes to construct EACQCs. Because the range of code length of almost MDS and $\hbar$-MDS codes is much more free than that of the commonly used MDS codes. We derive several families of new EACQCs with parameters better than the previously best known EAQECCs and standard quantum error-correcting codes (QECCs) of the same length and net transmissions. Moreover, we demonstrate that EACQCs are with maximal entanglement if both the inner and outer component codes are with maximal entanglement. As a result, we construct three new maximal-entanglement EACQCs which have optimal parameters. In addition, we present several new maximal-entanglement EACQCs whose minimum distance is only one less than the minimum distance of the optimal codes. In particular, we propose two new families of asymptotically good maximal-entanglement EACQCs with explicit constructions by using entanglement-assisted quantum algebraic geometry codes as the outer codes. At last, we prove that EACQCs can attain the quantum Gilbert-Varshamov bound for EAQECCs asymptotically. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.04921v1-abstract-full').style.display = 'none'; document.getElementById('2501.04921v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 8 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </p> <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 tables, 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/2412.19090">arXiv:2412.19090</a> <span> [<a href="https://arxiv.org/pdf/2412.19090">pdf</a>, <a href="https://arxiv.org/format/2412.19090">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 Algorithm for Vector Set Orthogonal Normalization and Matrix QR Decomposition with Polynomial Speedup </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zi-Ming Li</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+Y">Yu-xi 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="2412.19090v2-abstract-short" style="display: inline;"> Vector set orthogonal normalization and matrix QR decomposition are fundamental problems in matrix analysis with important applications in many fields. We know that Gram-Schmidt process is a widely used method to solve these two problems. However, the existing methods, including Gram-Schmidt process have problems of high complexity, scaling $O(N^3)$ in the system dimension $N$, which leads to diff… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.19090v2-abstract-full').style.display = 'inline'; document.getElementById('2412.19090v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.19090v2-abstract-full" style="display: none;"> Vector set orthogonal normalization and matrix QR decomposition are fundamental problems in matrix analysis with important applications in many fields. We know that Gram-Schmidt process is a widely used method to solve these two problems. However, the existing methods, including Gram-Schmidt process have problems of high complexity, scaling $O(N^3)$ in the system dimension $N$, which leads to difficulties when calculating large-scale or ill-conditioned problems. With the development of quantum information processing, a series of quantum algorithms have been proposed, providing advantages and speedups over classical algorithms in many fields. In this paper, we propose quantum algorithms to solve these two problems based on the idea of Gram-Schmidt process and quantum phase estimation. The complexity of proposed quantum algorithms is also theoretically and numerically analyzed. We find that our algorithms provide polynomial acceleration over the best-known classical and quantum algorithms on these two problems, scaling $O(N^2\mathrm{poly}(\log N))$ in the dimension $N$ of the system. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.19090v2-abstract-full').style.display = 'none'; document.getElementById('2412.19090v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 31 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 26 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">22 pages, 11 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2412.17929">arXiv:2412.17929</a> <span> [<a href="https://arxiv.org/pdf/2412.17929">pdf</a>, <a href="https://arxiv.org/format/2412.17929">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 Case for Quantum Circuit Cutting for NISQ Applications: Impact of topology, determinism, and sparsity </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zirui Li</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+M">Minghao Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Barad%2C+M">Mayank Barad</a>, <a href="/search/quant-ph?searchtype=author&query=Tang%2C+W">Wei Tang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+E+Z">Eddy Z. Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yipeng Huang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2412.17929v1-abstract-short" style="display: inline;"> We make the case that variational algorithm ansatzes for near-term quantum computing are well-suited for the quantum circuit cutting strategy. Previous demonstrations of circuit cutting focused on the exponential execution and postprocessing costs due to the cuts needed to partition a circuit topology, leading to overly pessimistic evaluations of the approach. This work observes that the ansatz Cl… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.17929v1-abstract-full').style.display = 'inline'; document.getElementById('2412.17929v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.17929v1-abstract-full" style="display: none;"> We make the case that variational algorithm ansatzes for near-term quantum computing are well-suited for the quantum circuit cutting strategy. Previous demonstrations of circuit cutting focused on the exponential execution and postprocessing costs due to the cuts needed to partition a circuit topology, leading to overly pessimistic evaluations of the approach. This work observes that the ansatz Clifford structure and variational parameter pruning significantly reduce these costs. By keeping track of the limited set of correct subcircuit initializations and measurements, we reduce the number of experiments needed by up to 16x, matching and beating the error mitigation offered by classical shadows tomography. By performing reconstruction as a sparse tensor contraction, we scale the feasible ansatzes to over 200 qubits with six ansatz layers, beyond the capability of prior work. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.17929v1-abstract-full').style.display = 'none'; document.getElementById('2412.17929v1-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 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2412.17636">arXiv:2412.17636</a> <span> [<a href="https://arxiv.org/pdf/2412.17636">pdf</a>, <a href="https://arxiv.org/format/2412.17636">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Discovery of an anomalous non-evaporating sub-nanometre water layer in open environment </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zhijie Li</a>, <a href="/search/quant-ph?searchtype=author&query=Kong%2C+X">Xi Kong</a>, <a href="/search/quant-ph?searchtype=author&query=Sun%2C+H">Haoyu Sun</a>, <a href="/search/quant-ph?searchtype=author&query=Qu%2C+G">Guanyu Qu</a>, <a href="/search/quant-ph?searchtype=author&query=Yu%2C+P">Pei Yu</a>, <a href="/search/quant-ph?searchtype=author&query=Xie%2C+T">Tianyu Xie</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+Z">Zhiyuan Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Shi%2C+G">Guoshen Shi</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Y">Ya Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Shi%2C+F">Fazhan Shi</a>, <a href="/search/quant-ph?searchtype=author&query=Du%2C+J">Jiangfeng Du</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2412.17636v1-abstract-short" style="display: inline;"> Water exhibits complex behaviors as a result of hydrogen bonding, and low-dimensional confined water plays a key role in material science, geology, and biology science. Conventional techniques like STM, TEM, and AFM enable atomic-scale observations but face limitations under ambient conditions and surface topographies. NV center magnetic resonance technology provides an opportunity to overcome the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.17636v1-abstract-full').style.display = 'inline'; document.getElementById('2412.17636v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.17636v1-abstract-full" style="display: none;"> Water exhibits complex behaviors as a result of hydrogen bonding, and low-dimensional confined water plays a key role in material science, geology, and biology science. Conventional techniques like STM, TEM, and AFM enable atomic-scale observations but face limitations under ambient conditions and surface topographies. NV center magnetic resonance technology provides an opportunity to overcome these limitations, offering non-contact atomic-scale measurements with chemical resolution capability. In this study, a nanoscale layer dissection method was developed utilizing NV center technology to analyze water layers with diverse physicochemical properties. It unveiled the presence of a non-evaporating sub-nanometer water layer on a diamond surface under ambient conditions. This layer demonstrated impervious to atmospheric water vapor and exhibited unique electronic transport mediated via hydrogen bonding. These findings provide new perspectives and a platform for studying the structure and behavior of low-dimensional water, as well as the surface properties influenced by adsorbed water under native conditions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.17636v1-abstract-full').style.display = 'none'; document.getElementById('2412.17636v1-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 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2412.12593">arXiv:2412.12593</a> <span> [<a href="https://arxiv.org/pdf/2412.12593">pdf</a>, <a href="https://arxiv.org/ps/2412.12593">ps</a>, <a href="https://arxiv.org/format/2412.12593">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"> Asymmetric protocols for mode pairing quantum key distribution with finite-key analysis </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zhenhua Li</a>, <a href="/search/quant-ph?searchtype=author&query=Dou%2C+T">Tianqi Dou</a>, <a href="/search/quant-ph?searchtype=author&query=Xie%2C+Y">Yuheng Xie</a>, <a href="/search/quant-ph?searchtype=author&query=Kong%2C+W">Weiwen Kong</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+Y">Yang Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Ma%2C+H">Haiqiang Ma</a>, <a href="/search/quant-ph?searchtype=author&query=Tang%2C+J">Jianjun Tang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2412.12593v2-abstract-short" style="display: inline;"> The mode pairing quantum key distribution (MP-QKD) protocol has attracted considerable attention for its capability to ensure high secure key rates over long distances without requiring global phase locking. However, ensuring symmetric channels for the MP-QKD protocol is challenging in practical quantum communication networks. Previous studies on the asymmetric MP-QKD protocol have relied on ideal… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.12593v2-abstract-full').style.display = 'inline'; document.getElementById('2412.12593v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.12593v2-abstract-full" style="display: none;"> The mode pairing quantum key distribution (MP-QKD) protocol has attracted considerable attention for its capability to ensure high secure key rates over long distances without requiring global phase locking. However, ensuring symmetric channels for the MP-QKD protocol is challenging in practical quantum communication networks. Previous studies on the asymmetric MP-QKD protocol have relied on ideal decoy state assumptions and infinite-key analysis, which are unattainable for real-world deployment. In this paper, we conduct a security analysis of asymmetric MP-QKD protocol with the finite-key analysis, where we discard the previously impractical assumptions made in the decoy-state method. Combined with statistical fluctuation analysis, we globally optimized the 12 independent parameters in the asymmetric MP-QKD protocol by employing our modified particle swarm optimization. The simulation results demonstrate that our work can achieve significantly enhanced secure key rates and transmission distances compared to the original strategy with adding extra attenuation. We further investigate the relationship between the intensities and probabilities of signal, decoy, and vacuum states with transmission distance, facilitating its more efficient deployment in future quantum networks. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.12593v2-abstract-full').style.display = 'none'; document.getElementById('2412.12593v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 17 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">9 pages, 6 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2412.12379">arXiv:2412.12379</a> <span> [<a href="https://arxiv.org/pdf/2412.12379">pdf</a>, <a href="https://arxiv.org/ps/2412.12379">ps</a>, <a href="https://arxiv.org/format/2412.12379">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Efficient Pumping of Spectral Holes in a Tm$^{3+}$: YAG Crystal for Broadband Quantum Optical Storage </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Lei%2C+Y">Yisheng Lei</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zongfeng Li</a>, <a href="/search/quant-ph?searchtype=author&query=Hosseini%2C+M">Mahdi Hosseini</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2412.12379v1-abstract-short" style="display: inline;"> Quantum memory devices with high storage efficiency and bandwidth are essential elements for future quantum networks. Here, we report a storage efficiency greater than 28% in a Tm$^{3+}$: YAG crystal in elevated temperatures and without compromising the memory bandwidth. Using various pumping and optimization techniques, we demonstrate multi-frequency window storage with a high memory bandwidth of… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.12379v1-abstract-full').style.display = 'inline'; document.getElementById('2412.12379v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.12379v1-abstract-full" style="display: none;"> Quantum memory devices with high storage efficiency and bandwidth are essential elements for future quantum networks. Here, we report a storage efficiency greater than 28% in a Tm$^{3+}$: YAG crystal in elevated temperatures and without compromising the memory bandwidth. Using various pumping and optimization techniques, we demonstrate multi-frequency window storage with a high memory bandwidth of 630 MHz. Moreover, we propose a general method for large-bandwidth atomic-frequency memory with non-Kramers rare-earth-ion (REI) in solids enabling significantly higher storage efficiency and bandwidth. Our study advances the practical applications of quantum memory devices based on REI-doped crystals. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.12379v1-abstract-full').style.display = 'none'; document.getElementById('2412.12379v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">7 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/2412.08067">arXiv:2412.08067</a> <span> [<a href="https://arxiv.org/pdf/2412.08067">pdf</a>, <a href="https://arxiv.org/format/2412.08067">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Emergent topological re-entrant phase transition in a generalized quasiperiodic modulated Su-Schrieffer-Heeger model </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wang%2C+X">Xiao-Ming Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shan-Zhong Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zhi 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="2412.08067v1-abstract-short" style="display: inline;"> We study the topological properties of the one-dimensional generalized quasiperiodic modulated Su-Schrieffer-Heeger model. The results reveal that topological re-entrant phase transition emerges. Through the analysis of a real-space winding number , we divide the emergent topological re-entrant phase transitions into two types. The first is the re-entrant phase transition from the traditional topo… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.08067v1-abstract-full').style.display = 'inline'; document.getElementById('2412.08067v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.08067v1-abstract-full" style="display: none;"> We study the topological properties of the one-dimensional generalized quasiperiodic modulated Su-Schrieffer-Heeger model. The results reveal that topological re-entrant phase transition emerges. Through the analysis of a real-space winding number , we divide the emergent topological re-entrant phase transitions into two types. The first is the re-entrant phase transition from the traditional topological insulator phase into the topological Anderson insulator phase, and the second is the re-entrant phenomenon from one topological Anderson insulator phase into another topological Anderson insulator phase. These two types of re-entrant phase transition correspond to bounded and unbounded cases of quasiperiodic modulation, respectively. Furthermore, we verify the above topological re-entrant phase transitions by analyzing the Lyapunov exponent and bulk gap. Since Su-Schrieffer-Heeger models have been realized in various artificial systems (such as cold atoms, optical waveguide arrays, ion traps, Rydberg atom arrays, etc.), the two types of topological re-entrant phase transition predicted in this paper are expected to be realized in the near future. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.08067v1-abstract-full').style.display = 'none'; document.getElementById('2412.08067v1-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 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2412.07593">arXiv:2412.07593</a> <span> [<a href="https://arxiv.org/pdf/2412.07593">pdf</a>, <a href="https://arxiv.org/format/2412.07593">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Chemical Physics">physics.chem-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"> Steering Non-Equilibrium Molecular Dynamics in Optical Cavities </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Xiao%2C+M">Mingxuan Xiao</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+W">Wei Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+W">Wenjing Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zheng Li</a>, <a href="/search/quant-ph?searchtype=author&query=Tang%2C+S">Shui-Jing Tang</a>, <a href="/search/quant-ph?searchtype=author&query=Xiao%2C+Y">Yun-Feng Xiao</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2412.07593v1-abstract-short" style="display: inline;"> Optical resonators have shown outstanding abilities to tailor chemical landscapes through enhanced light-matter interaction between confined optical modes and molecule vibrations. We propose a theoretical model to study cooperative vibrational strong coupling in an open quantum system. The non-equilibrium stochastic molecular dynamics in an optical cavity with an auxiliary ensemble is investigated… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.07593v1-abstract-full').style.display = 'inline'; document.getElementById('2412.07593v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.07593v1-abstract-full" style="display: none;"> Optical resonators have shown outstanding abilities to tailor chemical landscapes through enhanced light-matter interaction between confined optical modes and molecule vibrations. We propose a theoretical model to study cooperative vibrational strong coupling in an open quantum system. The non-equilibrium stochastic molecular dynamics in an optical cavity with an auxiliary ensemble is investigated. It shows that coupling with a cavity mode introduces an additional colored noise and a negative feedback, both of which enable control over thermalization rates (i.e. the lifetime of excitation) of reactive molecules. Our work offers a pathway to steer stability of chemical bonds for chemical reactivity under cooperative vibrational strong coupling. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.07593v1-abstract-full').style.display = 'none'; document.getElementById('2412.07593v1-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 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2412.05480">arXiv:2412.05480</a> <span> [<a href="https://arxiv.org/pdf/2412.05480">pdf</a>, <a href="https://arxiv.org/ps/2412.05480">ps</a>, <a href="https://arxiv.org/format/2412.05480">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Efficient Storage of Multidimensional Telecom Photons in a Solid-State Quantum Memory </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zongfeng Li</a>, <a href="/search/quant-ph?searchtype=author&query=Lei%2C+Y">Yisheng Lei</a>, <a href="/search/quant-ph?searchtype=author&query=Kling%2C+T">Trevor Kling</a>, <a href="/search/quant-ph?searchtype=author&query=Hosseini%2C+M">Mahdi Hosseini</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2412.05480v1-abstract-short" style="display: inline;"> Efficient storage of telecom-band quantum optical information represents a crucial milestone for establishing distributed quantum optical networks. Erbium ions in crystalline hosts provide a promising platform for telecom quantum memories; however, their practical applications have been hindered by demanding operational conditions, such as ultra-high magnetic fields and ultra-low temperatures. In… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.05480v1-abstract-full').style.display = 'inline'; document.getElementById('2412.05480v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.05480v1-abstract-full" style="display: none;"> Efficient storage of telecom-band quantum optical information represents a crucial milestone for establishing distributed quantum optical networks. Erbium ions in crystalline hosts provide a promising platform for telecom quantum memories; however, their practical applications have been hindered by demanding operational conditions, such as ultra-high magnetic fields and ultra-low temperatures. In this work, we demonstrate the storage of telecom photonic qubits encoded in polarization, frequency, and time-bin bases. Using the atomic frequency comb protocol in an Er$^{3+}$-doped crystal, we developed a memory initialization scheme that improves storage efficiency by over an order of magnitude under practical experimental conditions. Quantum process tomography further confirms the memory's performance, achieving a fidelity exceeding 92%. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.05480v1-abstract-full').style.display = 'none'; document.getElementById('2412.05480v1-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 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">24 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/2412.04702">arXiv:2412.04702</a> <span> [<a href="https://arxiv.org/pdf/2412.04702">pdf</a>, <a href="https://arxiv.org/format/2412.04702">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 Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Infinite Grassmann time-evolving matrix product operators for non-equilibrium quantum impurity problems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Sun%2C+Z">Zhijie Sun</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+R">Ruofan Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zhenyu Li</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+C">Chu 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="2412.04702v1-abstract-short" style="display: inline;"> An emergent numerical approach to solve quantum impurity problems is to encode the impurity path integral as a matrix product state. For time-dependent problems, the cost of this approach generally scales with the evolution time. Here we consider a common non-equilibrium scenario where an impurity, initially in equilibrium with a thermal bath, is driven out of equilibrium by a time-dependent force… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.04702v1-abstract-full').style.display = 'inline'; document.getElementById('2412.04702v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.04702v1-abstract-full" style="display: none;"> An emergent numerical approach to solve quantum impurity problems is to encode the impurity path integral as a matrix product state. For time-dependent problems, the cost of this approach generally scales with the evolution time. Here we consider a common non-equilibrium scenario where an impurity, initially in equilibrium with a thermal bath, is driven out of equilibrium by a time-dependent force term. Despite that there is no time-translational invariance in the problem, we show that we could still make full use of the infinite matrix product state technique, resulting in a method whose cost is essentially independent of the evolution time. We demonstrate the effectiveness of this method in the integrable case against exact diagonalization, and against existing calculations on the L-shaped Kadanoff-Baym contour in the general case. Our method could be a very competitive method for studying long-time non-equilibrium quantum dynamics, and be potentially used as an efficient impurity solver in the non-equilibrium dynamical mean field theory. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.04702v1-abstract-full').style.display = 'none'; document.getElementById('2412.04702v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">10 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/2411.18436">arXiv:2411.18436</a> <span> [<a href="https://arxiv.org/pdf/2411.18436">pdf</a>, <a href="https://arxiv.org/format/2411.18436">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Theory">hep-th</span> </div> </div> <p class="title is-5 mathjax"> Statistical features of quantum chaos using the Krylov operator complexity </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zhuoran Li</a>, <a href="/search/quant-ph?searchtype=author&query=Fan%2C+W">Wei Fan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2411.18436v2-abstract-short" style="display: inline;"> Recently the variance of Lanzcos coefficients in the Krylov space of an initial operator is recognized as an important indicator of quantum chaos. In this paper, we generate samples of random initial operators from given probability distribtions (GOE, GUE and the uniform distribution) and do statistics on the variance of Lanczos coefficients over these initial operators. Using the Sinai billiard w… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.18436v2-abstract-full').style.display = 'inline'; document.getElementById('2411.18436v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.18436v2-abstract-full" style="display: none;"> Recently the variance of Lanzcos coefficients in the Krylov space of an initial operator is recognized as an important indicator of quantum chaos. In this paper, we generate samples of random initial operators from given probability distribtions (GOE, GUE and the uniform distribution) and do statistics on the variance of Lanczos coefficients over these initial operators. Using the Sinai billiard with an integrability-breaking term, we propose two statistical quantities that have distinct behaviors as the system changes from nonchaotic to chaotic. One is the average correlation matrix $\langle x_{i} x_{j}\rangle$ of Lanczos coefficients, which exhibits different patterns in the nonchaotic and the chaotic regime. The other one is the resulting distribution of the variance of Lanzcos coefficients. In the nonchaotic case, the resulting distributions are almost overlapping together. In the chaotic case, they split into two well-separated groups. Furthermore, the resulting statistics of these two quantities are the Wishart distribution and the (rescaled) chi-square distribution respectively, which are independent of the distributions of initial operators and become the normal distribution in the case of large matrix size. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.18436v2-abstract-full').style.display = 'none'; document.getElementById('2411.18436v2-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 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 27 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.15360">arXiv:2411.15360</a> <span> [<a href="https://arxiv.org/pdf/2411.15360">pdf</a>, <a href="https://arxiv.org/format/2411.15360">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="Instrumentation and Detectors">physics.ins-det</span> </div> </div> <p class="title is-5 mathjax"> Boosting Photon-Number-Resolved Detection Rates of Transition-Edge Sensors by Machine Learning </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zhenghao Li</a>, <a href="/search/quant-ph?searchtype=author&query=Kendall%2C+M+J+H">Matthew J. H. Kendall</a>, <a href="/search/quant-ph?searchtype=author&query=Machado%2C+G+J">Gerard J. Machado</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+R">Ruidi Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Mer%2C+E">Ewan Mer</a>, <a href="/search/quant-ph?searchtype=author&query=Zhan%2C+H">Hao Zhan</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+A">Aonan Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Yu%2C+S">Shang Yu</a>, <a href="/search/quant-ph?searchtype=author&query=Walmsley%2C+I+A">Ian A. Walmsley</a>, <a href="/search/quant-ph?searchtype=author&query=Patel%2C+R+B">Raj B. Patel</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="2411.15360v1-abstract-short" style="display: inline;"> Transition-Edge Sensors (TESs) are very effective photon-number-resolving (PNR) detectors that have enabled many photonic quantum technologies. However, their relatively slow thermal recovery time severely limits their operation rate in experimental scenarios compared to leading non-PNR detectors. In this work, we develop an algorithmic approach that enables TESs to detect and accurately classify… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.15360v1-abstract-full').style.display = 'inline'; document.getElementById('2411.15360v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.15360v1-abstract-full" style="display: none;"> Transition-Edge Sensors (TESs) are very effective photon-number-resolving (PNR) detectors that have enabled many photonic quantum technologies. However, their relatively slow thermal recovery time severely limits their operation rate in experimental scenarios compared to leading non-PNR detectors. In this work, we develop an algorithmic approach that enables TESs to detect and accurately classify photon pulses without waiting for a full recovery time between detection events. We propose two machine-learning-based signal processing methods: one supervised learning method and one unsupervised clustering method. By benchmarking against data obtained using coherent states and squeezed states, we show that the methods extend the TES operation rate to 800 kHz, achieving at least a four-fold improvement, whilst maintaining accurate photon-number assignment up to at least five photons. Our algorithms will find utility in applications where high rates of PNR detection are required and in technologies which demand fast active feed-forward of PNR detection outcomes. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.15360v1-abstract-full').style.display = 'none'; document.getElementById('2411.15360v1-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 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">18 pages, 7 figures including supplimental material</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.13331">arXiv:2411.13331</a> <span> [<a href="https://arxiv.org/pdf/2411.13331">pdf</a>, <a href="https://arxiv.org/format/2411.13331">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Versatile photonic frequency synthetic dimensions using a single Mach-Zehnder-interferometer-assisted device on thin-film lithium niobate </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zhao-An Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zeng%2C+X">Xiao-Dong Zeng</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Y">Yi-Tao Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Ren%2C+J">Jia-Ming Ren</a>, <a href="/search/quant-ph?searchtype=author&query=Ao%2C+C">Chun Ao</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zhi-Peng Li</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+W">Wei Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+N">Nai-Jie Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Xie%2C+L">Lin-Ke Xie</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+J">Jun-You Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Ma%2C+Y">Yu-Hang Ma</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Ya-Qi Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+S">Shuang Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Tang%2C+J">Jian-Shun Tang</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="2411.13331v1-abstract-short" style="display: inline;"> Investigating physical models with photonic synthetic dimensions has been generating great interest in vast fields of science. The rapid developing thin-film lithium niobate (TFLN) platform, for its numerous advantages including high electro-optic coefficient and scalability, is well compatible with the realization of synthetic dimensions in the frequency together with spatial domain. While coupli… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.13331v1-abstract-full').style.display = 'inline'; document.getElementById('2411.13331v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.13331v1-abstract-full" style="display: none;"> Investigating physical models with photonic synthetic dimensions has been generating great interest in vast fields of science. The rapid developing thin-film lithium niobate (TFLN) platform, for its numerous advantages including high electro-optic coefficient and scalability, is well compatible with the realization of synthetic dimensions in the frequency together with spatial domain. While coupling resonators with fixed beam splitters is a common experimental approach, it often lacks tunability and limits coupling between adjacent lattices to sites occupying the same frequency domain positions. Here, on the contrary, we conceive the resonator arrays connected by electro-optic tunable Mach-Zehnder interferometers in our configuration instead of fixed beam splitters. By applying bias voltage and RF modulation on the interferometers, our design extends such coupling to long-range scenario and allows for continuous tuning on each coupling strength and synthetic effective magnetic flux. Therefore, our design enriches controllable coupling types that are essential for building programmable lattice networks and significantly increases versatility. As the example, we experimentally fabricate a two-resonator prototype on the TFLN platform, and on this single chip we realize well-known models including tight-binding lattices, topological Hall ladder and Creutz ladder. We directly observe the band structures in the quasi-momentum space and important phenomena such as spin-momentum locking and the Aharonov-Bohm cage effect. These results demonstrate the potential for convenient simulations of more complex models in our configuration. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.13331v1-abstract-full').style.display = 'none'; document.getElementById('2411.13331v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 20 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.12631">arXiv:2411.12631</a> <span> [<a href="https://arxiv.org/pdf/2411.12631">pdf</a>, <a href="https://arxiv.org/format/2411.12631">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"> Optimal Geometry of Oscillators in Gravity-Induced Entanglement Experiments </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Tang%2C+Z">Ziqian Tang</a>, <a href="/search/quant-ph?searchtype=author&query=Xue%2C+H">Hanyu Xue</a>, <a href="/search/quant-ph?searchtype=author&query=Han%2C+Z">Zizhao Han</a>, <a href="/search/quant-ph?searchtype=author&query=Kan%2C+Z">Zikuan Kan</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zeji Li</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+Y">Yulong 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="2411.12631v3-abstract-short" style="display: inline;"> The interface between quantum mechanics and gravity remains an unresolved issue. Recent advances in precision measurement suggest that detecting gravity-induced entanglement in oscillator systems could provide key evidence for the quantum nature of gravity. However, thermal decoherence imposes strict constraints on system parameters. For entanglement to occur, mechanical frequency $蠅_m$, dissipati… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.12631v3-abstract-full').style.display = 'inline'; document.getElementById('2411.12631v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.12631v3-abstract-full" style="display: none;"> The interface between quantum mechanics and gravity remains an unresolved issue. Recent advances in precision measurement suggest that detecting gravity-induced entanglement in oscillator systems could provide key evidence for the quantum nature of gravity. However, thermal decoherence imposes strict constraints on system parameters. For entanglement to occur, mechanical frequency $蠅_m$, dissipation rate $纬_m$, environmental temperature $T$, oscillator density $蟻$, and the form factor $螞$-determined by the geometry and arrangement of oscillators-must satisfy a specific constraint. This constraint, intrinsic to the noise model, is considered universal and cannot be improved by quantum control. Given the difficulty in further optimizing $蠅_m$, $纬_m$, $蟻$, and $T$, optimizing $螞$ can relax the constraints on these parameters. In this work, we prove that the form factor has a supremum of $2蟺$, revealing a fundamental limit of the oscillator system. We propose designs that approach this supremum, nearly an order of magnitude higher than typical spherical oscillators. This optimization could ease experimental constraints and bring quantum gravity validation based on gravity-induced entanglement closer to realization. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.12631v3-abstract-full').style.display = 'none'; document.getElementById('2411.12631v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 25 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 19 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.09861">arXiv:2411.09861</a> <span> [<a href="https://arxiv.org/pdf/2411.09861">pdf</a>, <a href="https://arxiv.org/format/2411.09861">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"> Towards quantum-centric simulations of extended molecules: sample-based quantum diagonalization enhanced with density matrix embedding theory </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Shajan%2C+A">Akhil Shajan</a>, <a href="/search/quant-ph?searchtype=author&query=Kaliakin%2C+D">Danil Kaliakin</a>, <a href="/search/quant-ph?searchtype=author&query=Mitra%2C+A">Abhishek Mitra</a>, <a href="/search/quant-ph?searchtype=author&query=Moreno%2C+J+R">Javier Robledo Moreno</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zhen Li</a>, <a href="/search/quant-ph?searchtype=author&query=Motta%2C+M">Mario Motta</a>, <a href="/search/quant-ph?searchtype=author&query=Johnson%2C+C">Caleb Johnson</a>, <a href="/search/quant-ph?searchtype=author&query=Saki%2C+A+A">Abdullah Ash Saki</a>, <a href="/search/quant-ph?searchtype=author&query=Das%2C+S">Susanta Das</a>, <a href="/search/quant-ph?searchtype=author&query=Sitdikov%2C+I">Iskandar Sitdikov</a>, <a href="/search/quant-ph?searchtype=author&query=Mezzacapo%2C+A">Antonio Mezzacapo</a>, <a href="/search/quant-ph?searchtype=author&query=Merz%2C+K+M">Kenneth M. Merz Jr</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="2411.09861v2-abstract-short" style="display: inline;"> Computing ground-state properties of molecules is a promising application for quantum computers operating in concert with classical high-performance computing resources. Quantum embedding methods are a family of algorithms particularly suited to these computational platforms: they combine high-level calculations on active regions of a molecule with low-level calculations on the surrounding environ… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.09861v2-abstract-full').style.display = 'inline'; document.getElementById('2411.09861v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.09861v2-abstract-full" style="display: none;"> Computing ground-state properties of molecules is a promising application for quantum computers operating in concert with classical high-performance computing resources. Quantum embedding methods are a family of algorithms particularly suited to these computational platforms: they combine high-level calculations on active regions of a molecule with low-level calculations on the surrounding environment, thereby avoiding expensive high-level full-molecule calculations and allowing to distribute computational cost across multiple and heterogeneous computing units. Here, we present the first density matrix embedding theory (DMET) simulations performed in combination with the sample-based quantum diagonalization (SQD) method. We employ the DMET-SQD formalism to compute the ground-state energy of a ring of 18 hydrogen atoms, and the relative energies of the chair, half-chair, twist-boat, and boat conformers of cyclohexane. The full-molecule 41- and 89-qubit simulations are decomposed into 27- and 32-qubit active-region simulations, that we carry out on the ibm_cleveland device, obtaining results in agreement with reference classical methods. Our DMET-SQD calculations mark a tangible progress in the size of active regions that can be accurately tackled by near-term quantum computers, and are an early demonstration of the potential for quantum-centric simulations to accurately treat the electronic structure of large molecules, with the ultimate goal of tackling systems such as peptides and proteins. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.09861v2-abstract-full').style.display = 'none'; document.getElementById('2411.09861v2-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 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 14 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.06026">arXiv:2411.06026</a> <span> [<a href="https://arxiv.org/pdf/2411.06026">pdf</a>, <a href="https://arxiv.org/format/2411.06026">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Atomic Physics">physics.atom-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="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"> Sub-Doppler cooling of a trapped ion in a phase-stable polarization gradient </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Clements%2C+E">Ethan Clements</a>, <a href="/search/quant-ph?searchtype=author&query=Knollmann%2C+F+W">Felix W. Knollmann</a>, <a href="/search/quant-ph?searchtype=author&query=Corsetti%2C+S">Sabrina Corsetti</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zhaoyi Li</a>, <a href="/search/quant-ph?searchtype=author&query=Hattori%2C+A">Ashton Hattori</a>, <a href="/search/quant-ph?searchtype=author&query=Notaros%2C+M">Milica Notaros</a>, <a href="/search/quant-ph?searchtype=author&query=Swint%2C+R">Reuel Swint</a>, <a href="/search/quant-ph?searchtype=author&query=Sneh%2C+T">Tal Sneh</a>, <a href="/search/quant-ph?searchtype=author&query=Kim%2C+M+E">May E. Kim</a>, <a href="/search/quant-ph?searchtype=author&query=Leu%2C+A+D">Aaron D. Leu</a>, <a href="/search/quant-ph?searchtype=author&query=Callahan%2C+P">Patrick Callahan</a>, <a href="/search/quant-ph?searchtype=author&query=Mahony%2C+T">Thomas Mahony</a>, <a href="/search/quant-ph?searchtype=author&query=West%2C+G+N">Gavin N. West</a>, <a href="/search/quant-ph?searchtype=author&query=Sorace-Agaskar%2C+C">Cheryl Sorace-Agaskar</a>, <a href="/search/quant-ph?searchtype=author&query=Kharas%2C+D">Dave Kharas</a>, <a href="/search/quant-ph?searchtype=author&query=McConnell%2C+R">Robert McConnell</a>, <a href="/search/quant-ph?searchtype=author&query=Bruzewicz%2C+C+D">Colin D. Bruzewicz</a>, <a href="/search/quant-ph?searchtype=author&query=Chuang%2C+I+L">Isaac L. Chuang</a>, <a href="/search/quant-ph?searchtype=author&query=Notaros%2C+J">Jelena Notaros</a>, <a href="/search/quant-ph?searchtype=author&query=Chiaverini%2C+J">John Chiaverini</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="2411.06026v1-abstract-short" style="display: inline;"> Trapped ions provide a highly controlled platform for quantum sensors, clocks, simulators, and computers, all of which depend on cooling ions close to their motional ground state. Existing methods like Doppler, resolved sideband, and dark resonance cooling balance trade-offs between the final temperature and cooling rate. A traveling polarization gradient has been shown to cool multiple modes quic… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.06026v1-abstract-full').style.display = 'inline'; document.getElementById('2411.06026v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.06026v1-abstract-full" style="display: none;"> Trapped ions provide a highly controlled platform for quantum sensors, clocks, simulators, and computers, all of which depend on cooling ions close to their motional ground state. Existing methods like Doppler, resolved sideband, and dark resonance cooling balance trade-offs between the final temperature and cooling rate. A traveling polarization gradient has been shown to cool multiple modes quickly and in parallel, but utilizing a stable polarization gradient can achieve lower ion energies, while also allowing more tailorable light-matter interactions in general. In this paper, we demonstrate cooling of a trapped ion below the Doppler limit using a phase-stable polarization gradient created using trap-integrated photonic devices. At an axial frequency of $2蟺\cdot1.45~ \rm MHz$ we achieve $\langle n \rangle = 1.3 \pm 1.1$ in $500~渭\rm s$ and cooling rates of ${\sim}0.3 \, \rm quanta/渭s$. We examine ion dynamics under different polarization gradient phases, detunings, and intensities, showing reasonable agreement between experimental results and a simple model. Cooling is fast and power-efficient, with improved performance compared to simulated operation under the corresponding running wave configuration. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.06026v1-abstract-full').style.display = 'none'; document.getElementById('2411.06026v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 8 November, 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">16 pages, 11 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.05501">arXiv:2411.05501</a> <span> [<a href="https://arxiv.org/pdf/2411.05501">pdf</a>, <a href="https://arxiv.org/format/2411.05501">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"> Multifunctional metalens for trapping and characterizing single atoms </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chen%2C+G">Guang-Jie Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+D">Dong Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zhu-Bo Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Ziqin Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+J">Ji-Zhe Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+L">Liang Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Y">Yan-Lei Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+X">Xin-Biao Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+A">Ai-Ping Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Dong%2C+C">Chun-Hua Dong</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+G">Guang-Can Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+K">Kun Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Zou%2C+C">Chang-Ling Zou</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="2411.05501v1-abstract-short" style="display: inline;"> Precise control and manipulation of neutral atoms are essential for quantum technologies but largely dependent on conventional bulky optical setups. Here, we demonstrate a multifunctional metalens that integrates an achromatic lens with large numerical aperture, a quarter-wave plate, and a polarizer for trapping and characterizing single Rubidium atoms. The metalens simultaneously focuses a trappi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.05501v1-abstract-full').style.display = 'inline'; document.getElementById('2411.05501v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.05501v1-abstract-full" style="display: none;"> Precise control and manipulation of neutral atoms are essential for quantum technologies but largely dependent on conventional bulky optical setups. Here, we demonstrate a multifunctional metalens that integrates an achromatic lens with large numerical aperture, a quarter-wave plate, and a polarizer for trapping and characterizing single Rubidium atoms. The metalens simultaneously focuses a trapping beam at 852\,nm and collects single-photon fluorescence at 780\,nm. We observe a strong dependence of the trapping lifetime on an external bias magnetic field, suggests a complex interplay between the circularly polarized trapping light and the atom's internal states. Our work showcases the potential of metasurfaces in realizing compact and integrated quantum systems based on cold atoms, opening up new possibilities for studying quantum control and manipulation at the nanoscale. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.05501v1-abstract-full').style.display = 'none'; document.getElementById('2411.05501v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 8 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">10 pages, 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/2411.04898">arXiv:2411.04898</a> <span> [<a href="https://arxiv.org/pdf/2411.04898">pdf</a>, <a href="https://arxiv.org/format/2411.04898">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Computational Complexity">cs.CC</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Information Theory">cs.IT</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mathematical Physics">math-ph</span> </div> </div> <p class="title is-5 mathjax"> Convergence efficiency of quantum gates and circuits </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Kong%2C+L">Linghang Kong</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zimu Li</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+Z">Zi-Wen 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="2411.04898v1-abstract-short" style="display: inline;"> We consider quantum circuit models where the gates are drawn from arbitrary gate ensembles given by probabilistic distributions over certain gate sets and circuit architectures, which we call stochastic quantum circuits. Of main interest in this work is the speed of convergence of stochastic circuits with different gate ensembles and circuit architectures to unitary t-designs. A key motivation for… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.04898v1-abstract-full').style.display = 'inline'; document.getElementById('2411.04898v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.04898v1-abstract-full" style="display: none;"> We consider quantum circuit models where the gates are drawn from arbitrary gate ensembles given by probabilistic distributions over certain gate sets and circuit architectures, which we call stochastic quantum circuits. Of main interest in this work is the speed of convergence of stochastic circuits with different gate ensembles and circuit architectures to unitary t-designs. A key motivation for this theory is the varying preference for different gates and circuit architectures in different practical scenarios. In particular, it provides a versatile framework for devising efficient circuits for implementing $t$-designs and relevant applications including random circuit and scrambling experiments, as well as benchmarking the performance of gates and circuit architectures. We examine various important settings in depth. A key aspect of our study is an "ironed gadget" model, which allows us to systematically evaluate and compare the convergence efficiency of entangling gates and circuit architectures. Particularly notable results include i) gadgets of two-qubit gates with KAK coefficients $\left(\frac蟺{4}-\frac{1}{8}\arccos(\frac{1}{5}),\frac蟺{8},\frac{1}{8}\arccos(\frac{1}{5})\right)$ (which we call $蠂$ gates) directly form exact 2- and 3-designs; ii) the iSWAP gate family achieves the best efficiency for convergence to 2-designs under mild conjectures with numerical evidence, even outperforming the Haar-random gate, for generic many-body circuits; iii) iSWAP + complete graph achieve the best efficiency for convergence to 2-designs among all graph circuits. A variety of numerical results are provided to complement our analysis. We also derive robustness guarantees for our analysis against gate perturbations. Additionally, we provide cursory analysis on gates with higher locality and found that the Margolus gate outperforms various other well-known gates. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.04898v1-abstract-full').style.display = 'none'; document.getElementById('2411.04898v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 7 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2024. </p> <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">50 pages + 8 tables + 6 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.04893">arXiv:2411.04893</a> <span> [<a href="https://arxiv.org/pdf/2411.04893">pdf</a>, <a href="https://arxiv.org/ps/2411.04893">ps</a>, <a href="https://arxiv.org/format/2411.04893">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Statistical Mechanics">cond-mat.stat-mech</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Information Theory">cs.IT</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mathematical Physics">math-ph</span> </div> </div> <p class="title is-5 mathjax"> Efficient quantum pseudorandomness under conservation laws </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zimu Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zheng%2C+H">Han Zheng</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+Z">Zi-Wen 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="2411.04893v2-abstract-short" style="display: inline;"> The efficiency of locally generating unitary designs, which capture statistical notions of quantum pseudorandomness, lies at the heart of wide-ranging areas in physics and quantum information technologies. While there are extensive potent methods and results for this problem, the evidently important setting where continuous symmetries or conservation laws (most notably U(1) and SU(d)) are involved… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.04893v2-abstract-full').style.display = 'inline'; document.getElementById('2411.04893v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.04893v2-abstract-full" style="display: none;"> The efficiency of locally generating unitary designs, which capture statistical notions of quantum pseudorandomness, lies at the heart of wide-ranging areas in physics and quantum information technologies. While there are extensive potent methods and results for this problem, the evidently important setting where continuous symmetries or conservation laws (most notably U(1) and SU(d)) are involved is known to present fundamental difficulties. In particular, even the basic question of whether any local symmetric circuit can generate 2-designs efficiently (in time that grows at most polynomially in the system size) remains open with no circuit constructions provably known to do so, despite intensive efforts. In this work, we resolve this long-standing open problem for both U(1) and SU(d) symmetries by explicitly constructing local symmetric quantum circuits which we prove to converge to symmetric unitary 2-designs in polynomial time using a combination of representation theory, graph theory, and Markov chain methods. As a direct application, our constructions can be used to efficiently generate near-optimal covariant quantum error-correcting codes, confirming a conjecture in [PRX Quantum 3, 020314 (2022)]. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.04893v2-abstract-full').style.display = 'none'; document.getElementById('2411.04893v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 7 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">9 + 48 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/2411.03953">arXiv:2411.03953</a> <span> [<a href="https://arxiv.org/pdf/2411.03953">pdf</a>, <a href="https://arxiv.org/format/2411.03953">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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"> Emergent dynamical quantum phase transition in a $Z_3$ symmetric chiral clock model </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Yu%2C+L">Ling-Feng Yu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+W">Wei-Lin Li</a>, <a href="/search/quant-ph?searchtype=author&query=Yu%2C+X">Xue-Jia Yu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zhi 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="2411.03953v1-abstract-short" style="display: inline;"> We study the quench dynamics in a $Z_3$ symmetric chiral clock model (CCM). The results reveal that chiral phases can lead to the emergence of dynamical quantum phase transition (DQPT). By analyzing Lee-Yang-Fisher zeros' distribution in the complex plane, we uncover the relation between the chiral phase and the emergence of DQPT. In concrete terms, only by taking some special angles can DQPT be i… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.03953v1-abstract-full').style.display = 'inline'; document.getElementById('2411.03953v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.03953v1-abstract-full" style="display: none;"> We study the quench dynamics in a $Z_3$ symmetric chiral clock model (CCM). The results reveal that chiral phases can lead to the emergence of dynamical quantum phase transition (DQPT). By analyzing Lee-Yang-Fisher zeros' distribution in the complex plane, we uncover the relation between the chiral phase and the emergence of DQPT. In concrete terms, only by taking some special angles can DQPT be induced. We confirm the above relation by computing the non-analytic points in Loschmidt echo return rate function. Furthermore, through the analysis of the corresponding dynamical partition function, we reveal the mechanism of the emergent DQPT and deduce the analytical expression of dynamical partition function's zero points' coordinates. Based on the analytic expression, one can obtain all the angles that induce DQPT's emergence and predict more possible DQPT in the system. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.03953v1-abstract-full').style.display = 'none'; document.getElementById('2411.03953v1-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">8 pages, 5 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.23562">arXiv:2410.23562</a> <span> [<a href="https://arxiv.org/pdf/2410.23562">pdf</a>, <a href="https://arxiv.org/format/2410.23562">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"> Measurement-Device-Independent Quantum Secret Sharing Networks with Linear Bell-State Analysis </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Liu%2C+T">Tianqi Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Lai%2C+J">Jiancheng Lai</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zhenhua Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+T">Tao 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="2410.23562v1-abstract-short" style="display: inline;"> Quantum secret sharing (QSS) plays a pivotal role in multiparty quantum communication, ensuring the secure distribution of private information among multiple parties. However, the security of QSS schemes can be compromised by attacks exploiting imperfections in measurement devices. Here, we propose a reconfigurable approach to implement QSS based on measurement-device-independent (MDI) principles,… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.23562v1-abstract-full').style.display = 'inline'; document.getElementById('2410.23562v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.23562v1-abstract-full" style="display: none;"> Quantum secret sharing (QSS) plays a pivotal role in multiparty quantum communication, ensuring the secure distribution of private information among multiple parties. However, the security of QSS schemes can be compromised by attacks exploiting imperfections in measurement devices. Here, we propose a reconfigurable approach to implement QSS based on measurement-device-independent (MDI) principles, utilizing linear two-photon Bell state analysis.By employing single-qubit conjugate operations for encoding private information, our approach offers reconfigurability, allowing for the inclusion of additional quantum network nodes without sacrificing efficiency. Furthermore, we demonstrate the robust security of our MDI-QSS scheme against inter-eavesdropping by dishonest participants and establish lower bounds for secure communication among three legitimate parties. This work presents a flexible configuration for implementing multiparty secure quantum communication with imperfect measurement devices and represents a significant advancement in the development of secure quantum communication technologies. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.23562v1-abstract-full').style.display = 'none'; document.getElementById('2410.23562v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 October, 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">9 pages, 3 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.22990">arXiv:2410.22990</a> <span> [<a href="https://arxiv.org/pdf/2410.22990">pdf</a>, <a href="https://arxiv.org/format/2410.22990">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Chemical Physics">physics.chem-ph</span> </div> </div> <p class="title is-5 mathjax"> Generalized many-body perturbation theory for the electron correlation energy </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Y">Yuqi Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Fang%2C+W">Wei-Hai Fang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zhendong 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="2410.22990v1-abstract-short" style="display: inline;"> Standard many-body perturbation theory (MBPT) using a quadratic zeroth-order Hamiltonian is a cornerstone of many \emph{ab initio} computational methods for molecules and materials. However, this perturbation expansion can break down in the presence of strong electron correlation, which occurs in many scenarios such as the bond dissociation of molecules in chemical reactions. In this work, we deve… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.22990v1-abstract-full').style.display = 'inline'; document.getElementById('2410.22990v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.22990v1-abstract-full" style="display: none;"> Standard many-body perturbation theory (MBPT) using a quadratic zeroth-order Hamiltonian is a cornerstone of many \emph{ab initio} computational methods for molecules and materials. However, this perturbation expansion can break down in the presence of strong electron correlation, which occurs in many scenarios such as the bond dissociation of molecules in chemical reactions. In this work, we developed a generalized (time-dependent) MBPT for computing electron correlation energies, in which the zeroth-order Hamiltonian can be interacting and hence the zeroth-order reference state is a multi-determinant wavefunction instead of a single Slater determinant in general. This allows us to take strong correlation into account from the outset and treat the residual weak interaction by diagrammatic perturbation expansion. Using this framework, we formulated a multi-reference (MR) generalization of the standard single-reference (SR) random phase approximation (RPA) for the electron correlation energy by resumming generalized ring diagrams including cumulant contributions, which naturally leads to a set of unified equations that work in both SR and MR cases. To further include exchange effects, we also derived a multi-reference second-order screened exchange (SOSEX) correction from a coupled-cluster perspective of the resulting MR-RPA. Applications to prototypical molecules demonstrate that MR-RPA/SOSEX successfully resolves the well-known failure of the conventional SR-RPA/SOSEX for molecular dissociation. Our work bridges MBPT in condensed matter physics and multi-reference perturbation theory in quantum chemistry, opening up new possibilities for advancing computational methods for the electron correlation energy via diagrammatic resummation. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.22990v1-abstract-full').style.display = 'none'; document.getElementById('2410.22990v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 October, 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">22 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/2410.21701">arXiv:2410.21701</a> <span> [<a href="https://arxiv.org/pdf/2410.21701">pdf</a>, <a href="https://arxiv.org/format/2410.21701">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 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.110.043311">10.1103/PhysRevA.110.043311 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Antichiral and trap-skin dynamics in a nonreciprocal bosonic two-leg ladder with artificial magnetic flux </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chen%2C+R">Rui-Jie Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+G">Guo-Qing Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zhi Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+D">Dan-Wei Zhang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2410.21701v1-abstract-short" style="display: inline;"> Non-Hermiticity and synthetic gauge fields play two fundamental roles in engineering exotic phases and dynamics in artificial quantum systems. Here we explore the mean-field dynamics of interacting bosons in a two-leg ladder with synthetic magnetic flux and nonreciprocal hopping under the open boundary condition. In the Hermitian limit, we showcase the breakdown of the flux-driven chiral dynamics… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.21701v1-abstract-full').style.display = 'inline'; document.getElementById('2410.21701v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.21701v1-abstract-full" style="display: none;"> Non-Hermiticity and synthetic gauge fields play two fundamental roles in engineering exotic phases and dynamics in artificial quantum systems. Here we explore the mean-field dynamics of interacting bosons in a two-leg ladder with synthetic magnetic flux and nonreciprocal hopping under the open boundary condition. In the Hermitian limit, we showcase the breakdown of the flux-driven chiral dynamics due to the nonlinear self-trapping effect. We further find that the nonreciprocity can drive the transition between chiral dynamics and antichiral dynamics. The antichiral motion is manifested as the non-Hermitian skin dynamics along the same direction on two legs that are not suppressed by the magnetic flux, while the chiral-antichiral transition is flux-tunable. We also reveal the trap-skin dynamics with the coexistence of the self-tapping and skin dynamics in the ladder. Dynamical phase diagrams with respect to the chiral-antichiral dynamics, skin dynamics, self-trapping dynamics, and trap-skin dynamics are presented. Our results shed light on intriguing dynamical phenomena under the interplay among non-Hermiticity, nonlinearity, and artificial gauge fields. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.21701v1-abstract-full').style.display = 'none'; document.getElementById('2410.21701v1-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">9 pages, 6 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. A 110, 043311 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.18854">arXiv:2410.18854</a> <span> [<a href="https://arxiv.org/pdf/2410.18854">pdf</a>, <a href="https://arxiv.org/format/2410.18854">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="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"> Preempting Fermion Sign Problem: Unveiling Quantum Criticality through Nonequilibrium Dynamics </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Yu%2C+Y">Yin-Kai Yu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zhi-Xuan Li</a>, <a href="/search/quant-ph?searchtype=author&query=Yin%2C+S">Shuai Yin</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zi-Xiang 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="2410.18854v1-abstract-short" style="display: inline;"> The notorious fermion sign problem, arising from fermion statistics, constitutes one of the main obstacles of deciphering quantum many-body systems by numerical approach. The progress in overcoming sign problem will definitely lead to a great leap in various areas of modern physics. Here, by deviating from the conventional cognition that nonequilibrium studies should be more complicated than equil… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.18854v1-abstract-full').style.display = 'inline'; document.getElementById('2410.18854v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.18854v1-abstract-full" style="display: none;"> The notorious fermion sign problem, arising from fermion statistics, constitutes one of the main obstacles of deciphering quantum many-body systems by numerical approach. The progress in overcoming sign problem will definitely lead to a great leap in various areas of modern physics. Here, by deviating from the conventional cognition that nonequilibrium studies should be more complicated than equilibrium cases, we propose an innovative framework based on nonequilibrium critical dynamics to preempt sign problem and investigate quantum critical point in fermionic model through numerically exact quantum Monte Carlo (QMC) simulation. By virtue of universal scaling theory of imaginary-time relaxation dynamics, we demonstrate that accurate critical point and critical exponents can be obtained in the short-time stage, in which the sign problem is not severe such that the QMC is accessible. After confirming the effectiveness of the method in two typical interacting fermionic models featuring Dirac quantum critical point (QCP), we for the first time reveal the quantum phase diagram in the Hubbard model hosting $\rm SU(3)$-symmetric Dirac fermions, and find that the QCP between Dirac semi-metal and a $位_8$-antiferromagnetic phase belongs to a new universality class different from the previously known Gross-Neveu transitions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.18854v1-abstract-full').style.display = 'none'; document.getElementById('2410.18854v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 24 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+13 pages</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.14538">arXiv:2410.14538</a> <span> [<a href="https://arxiv.org/pdf/2410.14538">pdf</a>, <a href="https://arxiv.org/format/2410.14538">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Nearly query-optimal classical shadow estimation of unitary channels </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zihao Li</a>, <a href="/search/quant-ph?searchtype=author&query=Yi%2C+C">Changhao Yi</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Y">You Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+H">Huangjun Zhu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2410.14538v1-abstract-short" style="display: inline;"> Classical shadow estimation (CSE) is a powerful tool for learning properties of quantum states and quantum processes. Here we consider the CSE task for quantum unitary channels. By querying an unknown unitary channel $\mathcal{U}$ multiple times in quantum experiments, the goal is to learn a classical description of $\mathcal{U}$ such that one can later use it to accurately predict many different… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.14538v1-abstract-full').style.display = 'inline'; document.getElementById('2410.14538v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.14538v1-abstract-full" style="display: none;"> Classical shadow estimation (CSE) is a powerful tool for learning properties of quantum states and quantum processes. Here we consider the CSE task for quantum unitary channels. By querying an unknown unitary channel $\mathcal{U}$ multiple times in quantum experiments, the goal is to learn a classical description of $\mathcal{U}$ such that one can later use it to accurately predict many different linear properties of the channel, i.e., the expectation values of arbitrary observables measured on the output of $\mathcal{U}$ upon arbitrary input states. Based on collective measurements on multiple systems, we propose a query efficient protocol for this task, whose query complexity achieves a quadratic advantage over previous best approach for this problem, and almost saturates the information-theoretic lower bound. To enhance practicality, we also present a variant protocol using only single-copy measurements, which still offers better query performance than any previous protocols that do not use additional quantum memories. In addition to linear properties, our protocol can also be applied to simultaneously predict many non-linear properties such as out-of-time-ordered correlators. Given the importance of CSE, this work may represent a significant advance in the study of learning unitary channels. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.14538v1-abstract-full').style.display = 'none'; document.getElementById('2410.14538v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 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">13+23 pages, 3 figures, and 1+5 tables; comments and suggestions 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/2410.09209">arXiv:2410.09209</a> <span> [<a href="https://arxiv.org/pdf/2410.09209">pdf</a>, <a href="https://arxiv.org/format/2410.09209">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"> Accurate quantum-centric simulations of supramolecular interactions </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Kaliakin%2C+D">Danil Kaliakin</a>, <a href="/search/quant-ph?searchtype=author&query=Shajan%2C+A">Akhil Shajan</a>, <a href="/search/quant-ph?searchtype=author&query=Moreno%2C+J+R">Javier Robledo Moreno</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zhen Li</a>, <a href="/search/quant-ph?searchtype=author&query=Mitra%2C+A">Abhishek Mitra</a>, <a href="/search/quant-ph?searchtype=author&query=Motta%2C+M">Mario Motta</a>, <a href="/search/quant-ph?searchtype=author&query=Johnson%2C+C">Caleb Johnson</a>, <a href="/search/quant-ph?searchtype=author&query=Saki%2C+A+A">Abdullah Ash Saki</a>, <a href="/search/quant-ph?searchtype=author&query=Das%2C+S">Susanta Das</a>, <a href="/search/quant-ph?searchtype=author&query=Sitdikov%2C+I">Iskandar Sitdikov</a>, <a href="/search/quant-ph?searchtype=author&query=Mezzacapo%2C+A">Antonio Mezzacapo</a>, <a href="/search/quant-ph?searchtype=author&query=Merz%2C+K+M">Kenneth M. Merz Jr</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="2410.09209v2-abstract-short" style="display: inline;"> We present the first quantum-centric simulations of noncovalent interactions using a supramolecular approach. We simulate the potential energy surfaces (PES) of the water and methane dimers, featuring hydrophilic and hydrophobic interactions, respectively, with a sample-based quantum diagonalization (SQD) approach. Our simulations on quantum processors, using 27- and 36-qubit circuits, are in rema… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.09209v2-abstract-full').style.display = 'inline'; document.getElementById('2410.09209v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.09209v2-abstract-full" style="display: none;"> We present the first quantum-centric simulations of noncovalent interactions using a supramolecular approach. We simulate the potential energy surfaces (PES) of the water and methane dimers, featuring hydrophilic and hydrophobic interactions, respectively, with a sample-based quantum diagonalization (SQD) approach. Our simulations on quantum processors, using 27- and 36-qubit circuits, are in remarkable agreement with classical methods, deviating from complete active space configuration interaction (CASCI) and coupled-cluster singles, doubles, and perturbative triples (CCSD(T)) within 1 kcal/mol in the equilibrium regions of the PES. Finally, we test the capacity limits of the quantum methods for capturing hydrophobic interactions with an experiment on 54 qubits. These results mark significant progress in the application of quantum computing to chemical problems, paving the way for more accurate modeling of noncovalent interactions in complex systems critical to the biological, chemical and pharmaceutical sciences. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.09209v2-abstract-full').style.display = 'none'; document.getElementById('2410.09209v2-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 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 11 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/2410.05394">arXiv:2410.05394</a> <span> [<a href="https://arxiv.org/pdf/2410.05394">pdf</a>, <a href="https://arxiv.org/format/2410.05394">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Statistical Mechanics">cond-mat.stat-mech</span> </div> </div> <p class="title is-5 mathjax"> Measurement-induced phase transitions in monitored infinite-range interacting systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Delmonte%2C+A">Anna Delmonte</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zejian Li</a>, <a href="/search/quant-ph?searchtype=author&query=Passarelli%2C+G">Gianluca Passarelli</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+E+Y">Eric Yilun Song</a>, <a href="/search/quant-ph?searchtype=author&query=Barberena%2C+D">Diego Barberena</a>, <a href="/search/quant-ph?searchtype=author&query=Rey%2C+A+M">Ana Maria Rey</a>, <a href="/search/quant-ph?searchtype=author&query=Fazio%2C+R">Rosario Fazio</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="2410.05394v1-abstract-short" style="display: inline;"> A key challenge in observing measurement-induced phase transitions is the mitigation of the post-selection barrier, which causes the reproducibility of specific sequences of measurement readouts--the trajectory--to be exponentially small in system size. Recent studies suggest that some classes of monitored infinite-range systems alleviate this problem by exhibiting a fast saturation of entanglemen… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.05394v1-abstract-full').style.display = 'inline'; document.getElementById('2410.05394v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.05394v1-abstract-full" style="display: none;"> A key challenge in observing measurement-induced phase transitions is the mitigation of the post-selection barrier, which causes the reproducibility of specific sequences of measurement readouts--the trajectory--to be exponentially small in system size. Recent studies suggest that some classes of monitored infinite-range systems alleviate this problem by exhibiting a fast saturation of entanglement, resulting in only a polynomial post-selection overhead. This paper answers whether this feature is inherent in infinite-range systems, due to their underlying semiclassical dynamics. We consider three experimentally relevant monitored models: a Tavis-Cummings model, a Superradiance model, and a Bose-Hubbard dimer, each exhibiting non-trivial monitored dynamics. We unveil the occurrence of entanglement phase transitions in these models, showing how the saturation time is strongly affected by bistability regions, which also prevent the mitigation of the post-selection barrier. Finally, we propose experimental realizations of these models, providing a discussion of post selection from an experimental perspective. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.05394v1-abstract-full').style.display = 'none'; document.getElementById('2410.05394v1-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 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">31 pages, 27 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.04469">arXiv:2410.04469</a> <span> [<a href="https://arxiv.org/pdf/2410.04469">pdf</a>, <a href="https://arxiv.org/format/2410.04469">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"> Emergent Matryoshka doll-like point gap in a non-Hermitian quasiperiodic lattice </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zheng%2C+Y">Yi-Qi Zheng</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shan-Zhong Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zhi 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="2410.04469v1-abstract-short" style="display: inline;"> We propose a geometric series modulated non-Hermitian quasiperiodic lattice model, and explore its localization and topological properties. The results show that with the ever-increasing summation terms of the geometric series, multiple mobility edges and non-Hermitian point gaps with high winding number can be induced in the system. The point gap spectrum of the system has a Matryoshka doll-like… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.04469v1-abstract-full').style.display = 'inline'; document.getElementById('2410.04469v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.04469v1-abstract-full" style="display: none;"> We propose a geometric series modulated non-Hermitian quasiperiodic lattice model, and explore its localization and topological properties. The results show that with the ever-increasing summation terms of the geometric series, multiple mobility edges and non-Hermitian point gaps with high winding number can be induced in the system. The point gap spectrum of the system has a Matryoshka doll-like structure in the complex plane, resulting in a high winding number. In addition, we analyze the limit case of summation of infinite terms. The results show that the mobility edges merge together as only one mobility edge when summation terms are pushed to the limit. Meanwhile, the corresponding point gaps are merged into a ring with winding number equal to one. Through Avila's global theory, we give an analytical expression for mobility edges in the limit of infinite summation, reconfirming that mobility edges and point gaps do merge and will result in a winding number that is indeed equal to one. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.04469v1-abstract-full').style.display = 'none'; document.getElementById('2410.04469v1-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 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">main 6 pages, 7 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.02600">arXiv:2410.02600</a> <span> [<a href="https://arxiv.org/pdf/2410.02600">pdf</a>, <a href="https://arxiv.org/ps/2410.02600">ps</a>, <a href="https://arxiv.org/format/2410.02600">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Other Condensed Matter">cond-mat.other</span> <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"> Chaitin Phase Transition </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Purcell%2C+J">James Purcell</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zhi Li</a>, <a href="/search/quant-ph?searchtype=author&query=Cubitt%2C+T">Toby Cubitt</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="2410.02600v1-abstract-short" style="display: inline;"> We construct a family of Hamiltonians whose phase diagram is guaranteed to have a single phase transition, yet the location of this phase transition is uncomputable. The Hamiltonians $H(蠁)$ describe qudits on a two-dimensional square lattice with translationally invariant, nearest-neighbour interactions tuned by a continuous parameter $蠁\in(0,1]$. For all $蠁\in(0,1]$, $H(蠁)$ is in one of two phase… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.02600v1-abstract-full').style.display = 'inline'; document.getElementById('2410.02600v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.02600v1-abstract-full" style="display: none;"> We construct a family of Hamiltonians whose phase diagram is guaranteed to have a single phase transition, yet the location of this phase transition is uncomputable. The Hamiltonians $H(蠁)$ describe qudits on a two-dimensional square lattice with translationally invariant, nearest-neighbour interactions tuned by a continuous parameter $蠁\in(0,1]$. For all $蠁\in(0,1]$, $H(蠁)$ is in one of two phases, one a gapless phase, the other a gapped phase. The phase transition occurs when $蠁$ equals the Chaitin's constant $惟$, a well-defined real number that encodes the Halting problem, and hence is uncomputable for Turing machines and undecidable for any consistent recursive axiomatization of mathematics. Our result implies that no general algorithm exists to determine the phase diagrams even under the promise that the phase diagram is exceedingly simple, and illustrates how uncomputable numbers may manifest in physical systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.02600v1-abstract-full').style.display = 'none'; document.getElementById('2410.02600v1-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/2409.18167">arXiv:2409.18167</a> <span> [<a href="https://arxiv.org/pdf/2409.18167">pdf</a>, <a href="https://arxiv.org/format/2409.18167">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"> Optimal Quantum Purity Amplification </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zhaoyi Li</a>, <a href="/search/quant-ph?searchtype=author&query=Fu%2C+H">Honghao Fu</a>, <a href="/search/quant-ph?searchtype=author&query=Isogawa%2C+T">Takuya Isogawa</a>, <a href="/search/quant-ph?searchtype=author&query=Chuang%2C+I">Isaac Chuang</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="2409.18167v1-abstract-short" style="display: inline;"> Quantum purity amplification (QPA) offers a novel approach to counteracting the pervasive noise that degrades quantum states. We present the optimal QPA protocol for general quantum systems against global depolarizing noise, which has remained unknown for two decades. We construct and prove the optimality of our protocol, which demonstrates improved fidelity scaling compared to the best-known meth… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.18167v1-abstract-full').style.display = 'inline'; document.getElementById('2409.18167v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.18167v1-abstract-full" style="display: none;"> Quantum purity amplification (QPA) offers a novel approach to counteracting the pervasive noise that degrades quantum states. We present the optimal QPA protocol for general quantum systems against global depolarizing noise, which has remained unknown for two decades. We construct and prove the optimality of our protocol, which demonstrates improved fidelity scaling compared to the best-known methods. We explore the operational interpretation of the protocol and provide simple examples of how to compile it into efficient circuits for near-term experiments. Furthermore, we conduct numerical simulations to investigate the effectiveness of our protocol in the quantum simulation of Hamiltonian evolution, demonstrating its ability to enhance fidelity even under circuit-level noise. Our findings suggest that QPA could improve the performance of quantum information processing tasks, particularly in the context of Noisy Intermediate-Scale Quantum (NISQ) devices, where reducing the effect of noise with limited resources is critical. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.18167v1-abstract-full').style.display = 'none'; document.getElementById('2409.18167v1-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">7+15 pages, 4+5 figures, 0+2 tables. Comments are welcome!</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> MIT-CTP/5775 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2409.14661">arXiv:2409.14661</a> <span> [<a href="https://arxiv.org/pdf/2409.14661">pdf</a>, <a href="https://arxiv.org/format/2409.14661">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> <p class="title is-5 mathjax"> Spectral signatures of the Markovian to Non-Markovian transition in open quantum systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zeng-Zhao Li</a>, <a href="/search/quant-ph?searchtype=author&query=Yip%2C+C">Cho-Tung Yip</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+B">Bo 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="2409.14661v2-abstract-short" style="display: inline;"> We present a new approach for investigating the Markovian to non-Markovian transition in quantum aggregates strongly coupled to a vibrational bath through the analysis of linear absorption spectra. Utilizing hierarchical algebraic equations in the frequency domain, we elucidate how these spectra can effectively reveal transitions between Markovian and non-Markovian regimes, driven by the complex i… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.14661v2-abstract-full').style.display = 'inline'; document.getElementById('2409.14661v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.14661v2-abstract-full" style="display: none;"> We present a new approach for investigating the Markovian to non-Markovian transition in quantum aggregates strongly coupled to a vibrational bath through the analysis of linear absorption spectra. Utilizing hierarchical algebraic equations in the frequency domain, we elucidate how these spectra can effectively reveal transitions between Markovian and non-Markovian regimes, driven by the complex interplay of dissipation, aggregate-bath coupling, and intra-aggregate dipole-dipole interactions. Our results demonstrate that reduced dissipation induces spectral peak splitting, signaling the emergence of bath-induced non-Markovian effects. The spectral peak splitting can also be driven by enhanced dipole-dipole interactions, although the underlying mechanism differs from that of dissipation-induced splitting. Additionally, with an increase in aggregate-bath coupling strength, initially symmetric or asymmetric peaks with varying spectral amplitudes may merge under weak dipole-dipole interactions, whereas strong dipole-dipole interactions are more likely to cause peak splitting. Moreover, we find that spectral features serve as highly sensitive indicators for distinguishing the geometric structures of aggregates, while also unveiling the critical role geometry plays in shaping non-Markovian behavior. This study not only deepens our understanding of the Markovian to non-Markovian transition but also provides a robust framework for optimizing and controlling quantum systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.14661v2-abstract-full').style.display = 'none'; document.getElementById('2409.14661v2-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 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 22 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">13 pages, 9 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2409.06547">arXiv:2409.06547</a> <span> [<a href="https://arxiv.org/pdf/2409.06547">pdf</a>, <a href="https://arxiv.org/format/2409.06547">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="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"> Imaginary-time Mpemba effect in quantum many-body systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chang%2C+W">Wei-Xuan Chang</a>, <a href="/search/quant-ph?searchtype=author&query=Yin%2C+S">Shuai Yin</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+S">Shi-Xin Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zi-Xiang 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="2409.06547v1-abstract-short" style="display: inline;"> Various exotic phenomena emerge in non-equilibrium quantum many-body systems. The Mpemba effect, denoting the situation where a hot system freezes faster than the colder one, is a counterintuitive non-equilibrium phenomenon that has attracted enduring interest for more than half a century. In this Letter, we report a novel phenomenon of the Mpemba effect in the imaginary-time relaxation dynamics i… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.06547v1-abstract-full').style.display = 'inline'; document.getElementById('2409.06547v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.06547v1-abstract-full" style="display: none;"> Various exotic phenomena emerge in non-equilibrium quantum many-body systems. The Mpemba effect, denoting the situation where a hot system freezes faster than the colder one, is a counterintuitive non-equilibrium phenomenon that has attracted enduring interest for more than half a century. In this Letter, we report a novel phenomenon of the Mpemba effect in the imaginary-time relaxation dynamics in quantum many-body systems, dubbed as imaginary-time Mpemba effect (ITME). Through numerically exact quantum Monte-Carlo (QMC) simulation, we unambiguously demonstrate that in different classes of interacting quantum models, the initial states with higher energy are relaxed faster than lower-energy initial states in the process of imaginary-time relaxation. The emergence of ITME is intimately associated with the low-energy excitations in quantum many-body systems. More crucially, since imaginary-time dynamics is broadly applied in numerical simulation on the quantum many-body ground states, the discovery of ITME potentially provides a new pathway to expedite the quantum many-body computation, particularly for QMC involving the sign problem. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.06547v1-abstract-full').style.display = 'none'; document.getElementById('2409.06547v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">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">4.5+8 pages, 4+6 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2409.04223">arXiv:2409.04223</a> <span> [<a href="https://arxiv.org/pdf/2409.04223">pdf</a>, <a href="https://arxiv.org/format/2409.04223">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"> Recovering optimal precision in quantum sensing using imperfect control </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zi-Shen Li</a>, <a href="/search/quant-ph?searchtype=author&query=Long%2C+X">Xinyue Long</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+X">Xiaodong Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Lu%2C+D">Dawei Lu</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+Y">Yuxiang 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="2409.04223v1-abstract-short" style="display: inline;"> Quantum control plays a crucial role in enhancing precision scaling for quantum sensing. However, most existing protocols require perfect control, even though real-world devices inevitably have control imperfections. Here, we consider a fundamental setting of quantum sensing with imperfect clocks, where the duration of control pulses and the interrogation time are all subject to uncertainty. Under… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.04223v1-abstract-full').style.display = 'inline'; document.getElementById('2409.04223v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.04223v1-abstract-full" style="display: none;"> Quantum control plays a crucial role in enhancing precision scaling for quantum sensing. However, most existing protocols require perfect control, even though real-world devices inevitably have control imperfections. Here, we consider a fundamental setting of quantum sensing with imperfect clocks, where the duration of control pulses and the interrogation time are all subject to uncertainty. Under this scenario, we investigate the task of frequency estimation in the presence of a non-Markovian environment. We design a control strategy and prove that it outperforms any control-free strategies, recovering the optimal Heisenberg scaling up to a small error term that is intrinsic to this model. We further demonstrate the advantage of our control strategy via experiments on a nuclear magnetic resonance (NMR) platform. Our finding confirms that the advantage of quantum control in quantum sensing persists even in the presence of imperfections. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.04223v1-abstract-full').style.display = 'none'; document.getElementById('2409.04223v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 6 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">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">18 pages, 7 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2409.02533">arXiv:2409.02533</a> <span> [<a href="https://arxiv.org/pdf/2409.02533">pdf</a>, <a href="https://arxiv.org/format/2409.02533">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"> Shedding Light on the Future: Exploring Quantum Neural Networks through Optics </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Yu%2C+S">Shang Yu</a>, <a href="/search/quant-ph?searchtype=author&query=Jia%2C+Z">Zhian Jia</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+A">Aonan Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Mer%2C+E">Ewan Mer</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zhenghao Li</a>, <a href="/search/quant-ph?searchtype=author&query=Crescimanna%2C+V">Valerio Crescimanna</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+K">Kuan-Cheng Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Patel%2C+R+B">Raj B. Patel</a>, <a href="/search/quant-ph?searchtype=author&query=Walmsley%2C+I+A">Ian A. Walmsley</a>, <a href="/search/quant-ph?searchtype=author&query=Kaszlikowski%2C+D">Dagomir Kaszlikowski</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="2409.02533v1-abstract-short" style="display: inline;"> At the dynamic nexus of artificial intelligence and quantum technology, quantum neural networks (QNNs) play an important role as an emerging technology in the rapidly developing field of quantum machine learning. This development is set to revolutionize the applications of quantum computing. This article reviews the concept of QNNs and their physical realizations, particularly implementations base… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.02533v1-abstract-full').style.display = 'inline'; document.getElementById('2409.02533v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.02533v1-abstract-full" style="display: none;"> At the dynamic nexus of artificial intelligence and quantum technology, quantum neural networks (QNNs) play an important role as an emerging technology in the rapidly developing field of quantum machine learning. This development is set to revolutionize the applications of quantum computing. This article reviews the concept of QNNs and their physical realizations, particularly implementations based on quantum optics . We first examine the integration of quantum principles with classical neural network architectures to create QNNs. Some specific examples, such as the quantum perceptron, quantum convolutional neural networks, and quantum Boltzmann machines are discussed. Subsequently, we analyze the feasibility of implementing QNNs through photonics. The key challenge here lies in achieving the required non-linear gates, and measurement-induced approaches, among others, seem promising. To unlock the computational potential of QNNs, addressing the challenge of scaling their complexity through quantum optics is crucial. Progress in controlling quantum states of light is continuously advancing the field. Additionally, we have discovered that different QNN architectures can be unified through non-Gaussian operations. This insight will aid in better understanding and developing more complex QNN circuits. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.02533v1-abstract-full').style.display = 'none'; document.getElementById('2409.02533v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.17402">arXiv:2408.17402</a> <span> [<a href="https://arxiv.org/pdf/2408.17402">pdf</a>, <a href="https://arxiv.org/format/2408.17402">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Chemical Physics">physics.chem-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"> 1.5-Femtosecond Delay in Charge Transfer </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Matselyukh%2C+D+T">Danylo T. Matselyukh</a>, <a href="/search/quant-ph?searchtype=author&query=Rott%2C+F">Florian Rott</a>, <a href="/search/quant-ph?searchtype=author&query=Schnappinger%2C+T">Thomas Schnappinger</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+P">Pengju Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zheng Li</a>, <a href="/search/quant-ph?searchtype=author&query=Richardson%2C+J+O">Jeremy O. Richardson</a>, <a href="/search/quant-ph?searchtype=author&query=de+Vivie-Riedle%2C+R">Regina de Vivie-Riedle</a>, <a href="/search/quant-ph?searchtype=author&query=W%C3%B6rner%2C+H+J">Hans Jakob W枚rner</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="2408.17402v1-abstract-short" style="display: inline;"> The transfer of population between two intersecting quantum states is the most fundamental dynamical event that governs a broad variety of processes in physics, chemistry, biology and material science. Whereas any two-state description implies that population leaving one state instantaneously appears in the other state, we show that coupling to additional states, present in all real-world systems,… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.17402v1-abstract-full').style.display = 'inline'; document.getElementById('2408.17402v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.17402v1-abstract-full" style="display: none;"> The transfer of population between two intersecting quantum states is the most fundamental dynamical event that governs a broad variety of processes in physics, chemistry, biology and material science. Whereas any two-state description implies that population leaving one state instantaneously appears in the other state, we show that coupling to additional states, present in all real-world systems, can cause a measurable delay in population transfer. Using attosecond spectroscopy supported by advanced quantum-chemical calculations, we measure a delay of 1.46$\pm$0.41 fs at a charge-transfer state crossing in CF$_3$I$^+$, where an electron hole moves from the fluorine atoms to iodine. Our measurements also fully resolve the other fundamental quantum-dynamical processes involved in the charge-transfer reaction: a vibrational rearrangement time of 9.38$\pm$0.21 fs (during which the vibrational wave packet travels to the state crossing) and a population-transfer time of 2.3-2.4 fs. Our experimental results and theoretical simulations show that delays in population transfer readily appear in otherwise-adiabatic reactions and are typically on the order of 1 fs for intersecting molecular valence states. These results have implications for many research areas, such as atomic and molecular physics, charge transfer or light harvesting. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.17402v1-abstract-full').style.display = 'none'; document.getElementById('2408.17402v1-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">18 pages, 5 figures, article</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.09088">arXiv:2408.09088</a> <span> [<a href="https://arxiv.org/pdf/2408.09088">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"> Quantum encryption design overcomes Shannon's theorem to achieve perfect secrecy with reusable keys </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Hu%2C+Z">Zixuan Hu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zhenyu 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="2408.09088v3-abstract-short" style="display: inline;"> Shannon's perfect-secrecy theorem states that a perfect encryption system that yields zero information to the adversary must be a one-time pad (OTP) with the keys randomly generated and never reused. In this work we design the first encryption method (classical or quantum) that overcomes Shannon's theorem to achieve perfect secrecy with reusable keys. Because the mechanisms used are fundamentally… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.09088v3-abstract-full').style.display = 'inline'; document.getElementById('2408.09088v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.09088v3-abstract-full" style="display: none;"> Shannon's perfect-secrecy theorem states that a perfect encryption system that yields zero information to the adversary must be a one-time pad (OTP) with the keys randomly generated and never reused. In this work we design the first encryption method (classical or quantum) that overcomes Shannon's theorem to achieve perfect secrecy with reusable keys. Because the mechanisms used are fundamentally quantum, Shannon's theorem remains true in the classical regime. Consequently, the quantum encryption design demonstrates decisive quantum advantage by achieving a goal impossible for classical systems. Finally, the design has major practical advantages by not requiring authentication and having silent tampering detection. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.09088v3-abstract-full').style.display = 'none'; document.getElementById('2408.09088v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 16 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">Major revision: added two theorems with proofs, two new figures, and revised discussions on the practical aspects</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.06179">arXiv:2408.06179</a> <span> [<a href="https://arxiv.org/pdf/2408.06179">pdf</a>, <a href="https://arxiv.org/ps/2408.06179">ps</a>, <a href="https://arxiv.org/format/2408.06179">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 more generalized two-qubit symmetric quantum joint measurement </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=He%2C+Y">Ying-Qiu He</a>, <a href="/search/quant-ph?searchtype=author&query=Ding%2C+D">Dong Ding</a>, <a href="/search/quant-ph?searchtype=author&query=Gao%2C+T">Ting Gao</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zan-Jia Li</a>, <a href="/search/quant-ph?searchtype=author&query=Yan%2C+F">Feng-Li Yan</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="2408.06179v1-abstract-short" style="display: inline;"> A standard two-qubit joint measurement is the well-known Bell state measurement (BSM), in which each reduced state (traced out one qubit) is the completely mixed state. Recently, a novel quantum joint measurement named elegant joint measurement (EJM) has been proposed, where the reduced states of the EJM basis have tetrahedral symmetry. In this work, we first suggest a five-parameter entangled sta… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.06179v1-abstract-full').style.display = 'inline'; document.getElementById('2408.06179v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.06179v1-abstract-full" style="display: none;"> A standard two-qubit joint measurement is the well-known Bell state measurement (BSM), in which each reduced state (traced out one qubit) is the completely mixed state. Recently, a novel quantum joint measurement named elegant joint measurement (EJM) has been proposed, where the reduced states of the EJM basis have tetrahedral symmetry. In this work, we first suggest a five-parameter entangled state and reveal its inherent symmetry. Based on this, we define a more generalized EJM parameterized by $z$, $\varphi$ and $胃$, and provide the quantum circuits for preparing and detecting these basis states. There are three main results: (i) the previous single-parameter EJM can be directly obtained by specifying the parameters $z$ and $\varphi$; (ii) the initial unit vectors related to the four vertices of the regular tetrahedron are not limited to the original choice and not all the unit vectors in cylindrical coordinates are suitable for forming the EJM basis; and (iii) the reduced states of the present EJM basis can always form two mirrorimage tetrahedrons, robustly preserving its elegant properties. We focus on figuring out what kind of states the EJM basis belongs to and providing a method for constructing the more generalized three-parameter EJM, which may contribute to the multi-setting measurement and the potential applications for quantum information processing. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.06179v1-abstract-full').style.display = 'none'; document.getElementById('2408.06179v1-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 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, 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/2408.02390">arXiv:2408.02390</a> <span> [<a href="https://arxiv.org/pdf/2408.02390">pdf</a>, <a href="https://arxiv.org/format/2408.02390">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevA.110.052207">10.1103/PhysRevA.110.052207 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Dynamics of relativistic vortex electrons in external laser fields </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Ababekri%2C+M">Mamutjan Ababekri</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Y">Yu Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+R">Ren-Tong Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zhong-Peng Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+J">Jian-Xing 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="2408.02390v3-abstract-short" style="display: inline;"> Investigating the interactions of vortex electrons with electromagnetic fields is crucial for advancing particle acceleration techniques, scattering theory in background fields, and developing novel electron beams for material diagnostics. In this work, we systematically study the dynamics of relativistic vortex electrons during their head-on collisions with linearly polarized (LP) and circularly… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.02390v3-abstract-full').style.display = 'inline'; document.getElementById('2408.02390v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.02390v3-abstract-full" style="display: none;"> Investigating the interactions of vortex electrons with electromagnetic fields is crucial for advancing particle acceleration techniques, scattering theory in background fields, and developing novel electron beams for material diagnostics. In this work, we systematically study the dynamics of relativistic vortex electrons during their head-on collisions with linearly polarized (LP) and circularly polarized (CP) laser pulses, as well as their superposition. We develop a theoretical framework using Volkov-Bessel wave functions to describe the spatiotemporal characteristics of vortex electrons in these external fields. We show that the beam center of the vortex electron follows the classical trajectory of a point-charge electron while maintaining the transverse structure of both vortex eigenstates and superposition states. Specifically, CP laser pulses cause the beam center to rotate, while LP laser pulses induce a lateral shift. The combined effect of LP and CP laser pulses in a two-mode field results in a twisted spiral pattern. Our findings demonstrate the potential for versatile control of vortex electron beams using various laser modes, providing a foundation for future experimental and theoretical studies. This work serves as a benchmark reference for investigations into the manipulation of vortex electron beams using more realistic laser or other types of external fields. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.02390v3-abstract-full').style.display = 'none'; document.getElementById('2408.02390v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 9 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 5 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 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, 052207 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.20865">arXiv:2407.20865</a> <span> [<a href="https://arxiv.org/pdf/2407.20865">pdf</a>, <a href="https://arxiv.org/format/2407.20865">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"> Auxiliary-free replica shadow estimation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Liu%2C+Q">Qing Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zihao Li</a>, <a href="/search/quant-ph?searchtype=author&query=Yuan%2C+X">Xiao Yuan</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+H">Huangjun Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Y">You 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="2407.20865v1-abstract-short" style="display: inline;"> Efficiently measuring nonlinear properties, like the entanglement spectrum, is a significant yet challenging task from quantum information processing to many-body physics. Current methodologies often suffer from an exponential scaling of the sampling cost or require auxiliary qubits and deep quantum circuits. To address these limitations, we propose an efficient auxiliary-free replica shadow (AFRS… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.20865v1-abstract-full').style.display = 'inline'; document.getElementById('2407.20865v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.20865v1-abstract-full" style="display: none;"> Efficiently measuring nonlinear properties, like the entanglement spectrum, is a significant yet challenging task from quantum information processing to many-body physics. Current methodologies often suffer from an exponential scaling of the sampling cost or require auxiliary qubits and deep quantum circuits. To address these limitations, we propose an efficient auxiliary-free replica shadow (AFRS) framework, which leverages the power of the joint entangling operation on a few input replicas while integrating the mindset of shadow estimation. We rigorously prove that AFRS can offer exponential improvements in estimation accuracy compared with the conventional shadow method, and facilitate the simultaneous estimation of various nonlinear properties, unlike the destructive swap test. Additionally, we introduce an advanced local-AFRS variant tailored to estimating local observables with even constant-depth local quantum circuits, which significantly simplifies the experimental realization compared with the general swap test. Our work paves the way for the application of AFRS on near-term quantum hardware, opening new avenues for efficient and practical quantum measurements. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.20865v1-abstract-full').style.display = 'none'; document.getElementById('2407.20865v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">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">main(10 pages, 5 figures), appendix(16 pages, 6 figures), and 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/2407.15574">arXiv:2407.15574</a> <span> [<a href="https://arxiv.org/pdf/2407.15574">pdf</a>, <a href="https://arxiv.org/format/2407.15574">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"> Spin-orbit coupling mediated photon-like resonance for a single atom trapped in a symmetric double well </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Fan%2C+C">Changwei Fan</a>, <a href="/search/quant-ph?searchtype=author&query=Hu%2C+X">Xiaoxiao Hu</a>, <a href="/search/quant-ph?searchtype=author&query=Yan%2C+X">Xin Yan</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+H">Hongzheng Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zhiqiang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Xiao%2C+J">Jinpeng Xiao</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Y">Yajiang Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Luo%2C+X">Xiaobing Luo</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2407.15574v1-abstract-short" style="display: inline;"> We employ a method involving coherent periodic modulation of Raman laser intensity to induce resonance transitions between energy levels of a spin-orbit coupled atom in a symmetric double-well trap. By integrating photon-assisted tunneling (PAT) technique with spin-orbit coupling (SOC), we achieve resonance transitions between the predefined energy levels of the atom, thereby enabling further prec… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.15574v1-abstract-full').style.display = 'inline'; document.getElementById('2407.15574v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.15574v1-abstract-full" style="display: none;"> We employ a method involving coherent periodic modulation of Raman laser intensity to induce resonance transitions between energy levels of a spin-orbit coupled atom in a symmetric double-well trap. By integrating photon-assisted tunneling (PAT) technique with spin-orbit coupling (SOC), we achieve resonance transitions between the predefined energy levels of the atom, thereby enabling further precise control of the atom's dynamics. We observe that such photon-like resonance can induce a transition from a localized state to atomic Rabi oscillation between two wells, or effectively reduce tunneling as manifested by a quantum beating phenomenon. Moreover, such resonance transitions have the potential to induce spin flipping in a spin-orbit coupled atom. Additionally, the SOC-mediated transition from multiphoton resonance to fundamental resonance and the SOC-induced resonance suppression are also discovered. In these cases, the analytical results of the effective coupling coefficients of the resonance transition derived from a four-level model can account for the entire dynamics, demonstrating surprisingly good agreement with the numerically exact results based on the realistic continuous model. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.15574v1-abstract-full').style.display = 'none'; document.getElementById('2407.15574v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 July, 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">13 pages, 13 figures</span> </p> </li> </ol> <nav class="pagination is-small is-centered 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