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<button class="button is-small is-link">Go</button> </div> </div> </form> </div> </div> <nav class="pagination is-small is-centered breathe-horizontal" role="navigation" aria-label="pagination"> <a href="" class="pagination-previous is-invisible">Previous </a> <a href="/search/?searchtype=author&query=Zhou%2C+Z&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Zhou%2C+Z&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=Zhou%2C+Z&start=50" class="pagination-link " aria-label="Page 2" aria-current="page">2 </a> </li> <li> <a href="/search/?searchtype=author&query=Zhou%2C+Z&start=100" class="pagination-link " aria-label="Page 3" aria-current="page">3 </a> </li> <li> <a href="/search/?searchtype=author&query=Zhou%2C+Z&start=150" class="pagination-link " aria-label="Page 4" aria-current="page">4 </a> </li> <li> <a href="/search/?searchtype=author&query=Zhou%2C+Z&start=200" class="pagination-link " aria-label="Page 5" aria-current="page">5 </a> </li> <li> <a href="/search/?searchtype=author&query=Zhou%2C+Z&start=250" class="pagination-link " aria-label="Page 6" aria-current="page">6 </a> </li> <li> <a href="/search/?searchtype=author&query=Zhou%2C+Z&start=300" class="pagination-link " aria-label="Page 7" aria-current="page">7 </a> </li> </ul> </nav> <ol class="breathe-horizontal" start="1"> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.11485">arXiv:2411.11485</a> <span> [<a href="https://arxiv.org/pdf/2411.11485">pdf</a>, <a href="https://arxiv.org/ps/2411.11485">ps</a>, <a href="https://arxiv.org/format/2411.11485">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 Coherence: A Fundamental Resource for Establishing Genuine Multipartite Correlations </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zong Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Z">Zhihua Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Z">Zhihua Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+M">Ming Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zihang Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+C">Chengjie Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Fei%2C+S">Shao-Ming Fei</a>, <a href="/search/quant-ph?searchtype=author&query=Ma%2C+Z">Zhihao Ma</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2411.11485v1-abstract-short" style="display: inline;"> We establish the profound equivalence between measures of genuine multipartite entanglement(GME) and their corresponding coherence measures. Initially we construct two distinct classes of measures for genuine multipartite entanglement utilizing real symmetric concave functions and the convex roof technique. We then demonstrate that all coherence measures for any qudit states, defined through the c… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.11485v1-abstract-full').style.display = 'inline'; document.getElementById('2411.11485v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.11485v1-abstract-full" style="display: none;"> We establish the profound equivalence between measures of genuine multipartite entanglement(GME) and their corresponding coherence measures. Initially we construct two distinct classes of measures for genuine multipartite entanglement utilizing real symmetric concave functions and the convex roof technique. We then demonstrate that all coherence measures for any qudit states, defined through the convex roof approach, are identical to our two classes of GME measures of the states combined with an incoherent ancilla under a unitary incoherent operation. This relationship implies that genuine multipartite entanglement can be generated from the coherence inherent in an initial state through the unitary incoherent operations. Furthermore, we explore the interplay between coherence and other forms of genuine quantum correlations, specifically genuine multipartite steering and genuine multipartite nonlocality. In the instance of special three-qubit X-states (only nonzero elements of X-state are diagonal or antidiagonal when written in an orthonormal basis), we find that genuine multipartite steering and nonlocality are present if and only if the coherence exists in the corresponding qubit states. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.11485v1-abstract-full').style.display = 'none'; document.getElementById('2411.11485v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.11369">arXiv:2411.11369</a> <span> [<a href="https://arxiv.org/pdf/2411.11369">pdf</a>, <a href="https://arxiv.org/format/2411.11369">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"> Exact Quantum Algorithm for Unit Commitment Optimization based on Partially Connected Quantum Neural Networks </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Liu%2C+J">Jian Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+X">Xu Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zhuojun Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Luo%2C+L">Le 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="2411.11369v1-abstract-short" style="display: inline;"> The quantum hybrid algorithm has become a very promising and speedily method today for solving the larger-scale optimization in the noisy intermediate-scale quantum (NISQ) era. The unit commitment (UC) problem is a fundamental problem in the power system which aims to satisfy a balance load with minimal cost. In this paper, we focus on the implement of the UC-solving by exact quantum algorithms ba… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.11369v1-abstract-full').style.display = 'inline'; document.getElementById('2411.11369v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.11369v1-abstract-full" style="display: none;"> The quantum hybrid algorithm has become a very promising and speedily method today for solving the larger-scale optimization in the noisy intermediate-scale quantum (NISQ) era. The unit commitment (UC) problem is a fundamental problem in the power system which aims to satisfy a balance load with minimal cost. In this paper, we focus on the implement of the UC-solving by exact quantum algorithms based on the quantum neural network (QNN). This method is tested with up to 10-unit system with the balance load constraint. In order to improve the computing precision and reduce the network complexity, we suggest the knowledge-based partially connected quantum neural network (PCQNN). The results show that the exact solutions can be obtained by the improved algorithm and the depth of the quantum circuit can be reduced simultaneously. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.11369v1-abstract-full').style.display = 'none'; document.getElementById('2411.11369v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.04353">arXiv:2411.04353</a> <span> [<a href="https://arxiv.org/pdf/2411.04353">pdf</a>, <a href="https://arxiv.org/format/2411.04353">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="Computational Complexity">cs.CC</span> </div> </div> <p class="title is-5 mathjax"> On the hardness of learning ground state entanglement of geometrically local Hamiltonians </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Bouland%2C+A">Adam Bouland</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+C">Chenyi Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zixin 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="2411.04353v1-abstract-short" style="display: inline;"> Characterizing the entanglement structure of ground states of local Hamiltonians is a fundamental problem in quantum information. In this work we study the computational complexity of this problem, given the Hamiltonian as input. Our main result is that to show it is cryptographically hard to determine if the ground state of a geometrically local, polynomially gapped Hamiltonian on qudits (… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.04353v1-abstract-full').style.display = 'inline'; document.getElementById('2411.04353v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.04353v1-abstract-full" style="display: none;"> Characterizing the entanglement structure of ground states of local Hamiltonians is a fundamental problem in quantum information. In this work we study the computational complexity of this problem, given the Hamiltonian as input. Our main result is that to show it is cryptographically hard to determine if the ground state of a geometrically local, polynomially gapped Hamiltonian on qudits ($d=O(1)$) has near-area law vs near-volume law entanglement. This improves prior work of Bouland et al. (arXiv:2311.12017) showing this for non-geometrically local Hamiltonians. In particular we show this problem is roughly factoring-hard in 1D, and LWE-hard in 2D. Our proof works by constructing a novel form of public-key pseudo-entanglement which is highly space-efficient, and combining this with a modification of Gottesman and Irani's quantum Turing machine to Hamiltonian construction. Our work suggests that the problem of learning so-called "gapless" quantum phases of matter might be intractable. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.04353v1-abstract-full').style.display = 'none'; document.getElementById('2411.04353v1-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">47 pages, 10 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.03202">arXiv:2411.03202</a> <span> [<a href="https://arxiv.org/pdf/2411.03202">pdf</a>, <a href="https://arxiv.org/format/2411.03202">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"> Architectures for Heterogeneous Quantum Error Correction Codes </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Stein%2C+S">Samuel Stein</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+S">Shifan Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Cross%2C+A+W">Andrew W. Cross</a>, <a href="/search/quant-ph?searchtype=author&query=Yoder%2C+T+J">Theodore J. Yoder</a>, <a href="/search/quant-ph?searchtype=author&query=Javadi-Abhari%2C+A">Ali Javadi-Abhari</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+C">Chenxu Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+K">Kun Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zeyuan Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Guinn%2C+C">Charles Guinn</a>, <a href="/search/quant-ph?searchtype=author&query=Ding%2C+Y">Yufei Ding</a>, <a href="/search/quant-ph?searchtype=author&query=Ding%2C+Y">Yongshan Ding</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+A">Ang 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="2411.03202v3-abstract-short" style="display: inline;"> Quantum Error Correction (QEC) is essential for future quantum computers due to its ability to exponentially suppress physical errors. The surface code is a leading error-correcting code candidate because of its local topological structure, experimentally achievable thresholds, and support for universal gate operations with magic states. However, its physical overhead scales quadratically with num… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.03202v3-abstract-full').style.display = 'inline'; document.getElementById('2411.03202v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.03202v3-abstract-full" style="display: none;"> Quantum Error Correction (QEC) is essential for future quantum computers due to its ability to exponentially suppress physical errors. The surface code is a leading error-correcting code candidate because of its local topological structure, experimentally achievable thresholds, and support for universal gate operations with magic states. However, its physical overhead scales quadratically with number of correctable errors. Conversely, quantum low-density parity-check (qLDPC) codes offer superior scaling but lack, on their own, a clear path to universal logical computation. Therefore, it is becoming increasingly evident is becoming that there are significant advantages to designing architectures using multiple codes. Heterogeneous architectures provide a clear path to universal logical computation as well as the ability to access different resource trade offs. To address this, we propose integrating the surface code and gross code using an ancilla bus for inter-code data movement. This approach involves managing trade-offs, including qubit overhead, a constrained instruction set, and gross code (memory) routing and management. While our focus is on the gross-surface code architecture, our method is adaptable to any code combination and the constraints generated by that specific architecture. Motivated by the potential reduction of physical qubit overhead, an ever important feature in the realization of fault tolerant computation, we perform the first full system study of heterogeneous error-correcting codes, discovering architectural trade-offs and optimizing around them. We demonstrate physical qubit reductions of up to 6.42x when executing an algorithm to a specific logical error rate, at the cost of up to a 3.43x increase in execution time. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.03202v3-abstract-full').style.display = 'none'; document.getElementById('2411.03202v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 5 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.00428">arXiv:2411.00428</a> <span> [<a href="https://arxiv.org/pdf/2411.00428">pdf</a>, <a href="https://arxiv.org/ps/2411.00428">ps</a>, <a href="https://arxiv.org/format/2411.00428">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"> Shortcuts to adiabatic state transfer in time-modulated two-level non-Hermitian systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Q">Qi-Cheng Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+J">Jun-Long Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Y">Yan-Hui Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Ye%2C+B">Biao-Liang Ye</a>, <a href="/search/quant-ph?searchtype=author&query=Fang%2C+Y">Yu-Liang Fang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zheng-Wei Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+C">Chui-Ping 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="2411.00428v2-abstract-short" style="display: inline;"> Nontrivial spectral properties of non-Hermitian systems can give rise to intriguing effects that lack counterparts in Hermitian systems. For instance, when dynamically varying system parameters along a path enclosing an exceptional point (EP), chiral mode conversion occurs. A recent study [Phys. Rev. Lett. 133, 113802 (2024)] demonstrates the achievability of pure adiabatic state transfer by speci… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.00428v2-abstract-full').style.display = 'inline'; document.getElementById('2411.00428v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.00428v2-abstract-full" style="display: none;"> Nontrivial spectral properties of non-Hermitian systems can give rise to intriguing effects that lack counterparts in Hermitian systems. For instance, when dynamically varying system parameters along a path enclosing an exceptional point (EP), chiral mode conversion occurs. A recent study [Phys. Rev. Lett. 133, 113802 (2024)] demonstrates the achievability of pure adiabatic state transfer by specifically selecting a trajectory in the system parameter space where the corresponding evolution operator exhibits a real spectrum while winding around an EP. However, the intended adiabatic state transfer becomes fragile when taking into account the effect of the nonadiabatic transition. In this work, we propose a scheme for achieving robust and rapid adiabatic state transfer in time-modulated two-level non-Hermitian systems by appropriately modulating system Hamiltonian and time-evolution trajectory. Numerical simulations confirm that complete adiabatic transfer can always be achieved even under nonadiabatic conditions after one period for different initialized adiabatic states, and the scheme remains insensitive to moderate fluctuations in control parameters. Therefore, this scheme offers alternative approaches for quantum-state engineering in non-Hermitian systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.00428v2-abstract-full').style.display = 'none'; document.getElementById('2411.00428v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 1 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">7 pages, 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/2410.15389">arXiv:2410.15389</a> <span> [<a href="https://arxiv.org/pdf/2410.15389">pdf</a>, <a href="https://arxiv.org/format/2410.15389">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1126/sciadv.adr9527">10.1126/sciadv.adr9527 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Observation of quantum superposition of topological defects in a trapped ion quantum simulator </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Cheng%2C+Z">Zhijie Cheng</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yukai Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shijiao Li</a>, <a href="/search/quant-ph?searchtype=author&query=Mei%2C+Q">Quanxin Mei</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+B">Bowen Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+G">Gangxi Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Jiang%2C+Y">Yue Jiang</a>, <a href="/search/quant-ph?searchtype=author&query=Qi%2C+B">Binxiang Qi</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zichao Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Hou%2C+P">Panyu Hou</a>, <a href="/search/quant-ph?searchtype=author&query=Duan%2C+L">Luming Duan</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="2410.15389v1-abstract-short" style="display: inline;"> Topological defects are discontinuities of a system protected by global properties, with wide applications in mathematics and physics. While previous experimental studies mostly focused on their classical properties, it has been predicted that topological defects can exhibit quantum superposition. Despite the fundamental interest and potential applications in understanding symmetry-breaking dynami… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.15389v1-abstract-full').style.display = 'inline'; document.getElementById('2410.15389v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.15389v1-abstract-full" style="display: none;"> Topological defects are discontinuities of a system protected by global properties, with wide applications in mathematics and physics. While previous experimental studies mostly focused on their classical properties, it has been predicted that topological defects can exhibit quantum superposition. Despite the fundamental interest and potential applications in understanding symmetry-breaking dynamics of quantum phase transitions, its experimental realization still remains a challenge. Here, we report the observation of quantum superposition of topological defects in a trapped-ion quantum simulator. By engineering long-range spin-spin interactions, we observe a spin kink splitting into a superposition of kinks at different positions, creating a ``Schrodinger kink'' that manifests non-locality and quantum interference. Furthermore, by preparing superposition states of neighboring kinks with different phases, we observe the propagation of the wave packet in different directions, thus unambiguously verifying the quantum coherence in the superposition states. Our work provides useful tools for non-equilibrium dynamics in quantum Kibble-Zurek physics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.15389v1-abstract-full').style.display = 'none'; document.getElementById('2410.15389v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 20 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 pages, 6 figures, already published in Science Advances</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Sci. Adv.10,eadr9527(2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.12007">arXiv:2410.12007</a> <span> [<a href="https://arxiv.org/pdf/2410.12007">pdf</a>, <a href="https://arxiv.org/ps/2410.12007">ps</a>, <a href="https://arxiv.org/format/2410.12007">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Computational Physics">physics.comp-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"> Machine learning of the Ising model on a spherical Fibonacci lattice </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zheng Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+C">Chen-Hui Song</a>, <a href="/search/quant-ph?searchtype=author&query=Hou%2C+X">Xu-Yang Hou</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+H">Hao 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="2410.12007v1-abstract-short" style="display: inline;"> We investigate the Ising model confined to a spherical surface, focusing on its implementation using a Fibonacci lattice. The challenge lies in uniformly covering the spherical surface to enable reliable comparisons with planar models. Monte Carlo simulations and graph convolutional networks(GCNs) are employed to analyze spin configurations at varying temperatures and to identify phase transition… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.12007v1-abstract-full').style.display = 'inline'; document.getElementById('2410.12007v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.12007v1-abstract-full" style="display: none;"> We investigate the Ising model confined to a spherical surface, focusing on its implementation using a Fibonacci lattice. The challenge lies in uniformly covering the spherical surface to enable reliable comparisons with planar models. Monte Carlo simulations and graph convolutional networks(GCNs) are employed to analyze spin configurations at varying temperatures and to identify phase transition temperatures. Although the spherical Fibonacci lattice is sufficiently uniform, there are still some irregular sites, which introduce interesting effects. In the ferromagnetic case, sites with fewer neighbors are more likely to undergo spin flips at low temperatures; however, this is not necessarily true at high temperatures, which could explain why the phase transition temperature is higher compared to the planar Ising model. In the antiferromagnetic case, the presence of irregular sites results in the total energy of the system at zero temperature not being the lowest. Phase transition temperatures are estimated using specific heat analysis and GCNs, revealing $T_C$ values for both ferromagnetic and antiferromagnetic cases. The study underscores the significance of the Fibonacci lattice's geometric properties in understanding spin interactions in microgravity environments. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.12007v1-abstract-full').style.display = 'none'; document.getElementById('2410.12007v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 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 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/2410.05659">arXiv:2410.05659</a> <span> [<a href="https://arxiv.org/pdf/2410.05659">pdf</a>, <a href="https://arxiv.org/format/2410.05659">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Experimental realization of direct entangling gates between dual-type qubits </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wang%2C+C">Chenxi Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+C">Chuanxin Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+H">Hongxuan Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Hu%2C+H">Hongyuan Hu</a>, <a href="/search/quant-ph?searchtype=author&query=Mao%2C+Z">Zhichao Mao</a>, <a href="/search/quant-ph?searchtype=author&query=Hou%2C+P">Panyu Hou</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yukai Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zichao Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Duan%2C+L">Luming Duan</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="2410.05659v1-abstract-short" style="display: inline;"> Dual-type qubits have become a promising way to suppress the crosstalk error of auxiliary operations in large-scale ion trap quantum computation. Here we demonstrate a direct entangling gate between dual-type qubits encoded in the $S_{1/2}$ and $D_{5/2}$ hyperfine manifolds of $^{137}\mathrm{Ba}^{+}$ ions. Our scheme is economic in the hardware, requiring only a single $532\,$nm laser system to en… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.05659v1-abstract-full').style.display = 'inline'; document.getElementById('2410.05659v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.05659v1-abstract-full" style="display: none;"> Dual-type qubits have become a promising way to suppress the crosstalk error of auxiliary operations in large-scale ion trap quantum computation. Here we demonstrate a direct entangling gate between dual-type qubits encoded in the $S_{1/2}$ and $D_{5/2}$ hyperfine manifolds of $^{137}\mathrm{Ba}^{+}$ ions. Our scheme is economic in the hardware, requiring only a single $532\,$nm laser system to entangle both qubit types by driving their Raman transitions. We achieve a Bell state fidelity of $96.3(4)\%$ for the dual-type Molmer-Sorensen gate between an $S$-$D$ ion pair, comparable to that for the same-type $S$-$S$ or $D$-$D$ gates. This technique can reduce the overhead for back-and-forth conversions between dual-type qubits in the quantum circuit with wide applications in quantum error correction and ion-photon quantum networks. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.05659v1-abstract-full').style.display = 'none'; document.getElementById('2410.05659v1-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> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2409.14048">arXiv:2409.14048</a> <span> [<a href="https://arxiv.org/pdf/2409.14048">pdf</a>, <a href="https://arxiv.org/ps/2409.14048">ps</a>, <a href="https://arxiv.org/format/2409.14048">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"> Super-Heisenberg scaling in a triple point criticality </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Cheng%2C+J">Jia-Ming Cheng</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Y">Yong-Chang Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+X">Xiang-Fa Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zheng-Wei 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="2409.14048v1-abstract-short" style="display: inline;"> We investigate quantum-enhanced metrology in a triple point criticality and discover that quantum criticality can not always enhance measuring precision. We have developed suitable adiabatic evolution protocols approaching a final point around the triple point to effectively restrain excitations, which could accelerate the adiabatic evolutions and lead to an exponential super-Heisenberg scaling. T… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.14048v1-abstract-full').style.display = 'inline'; document.getElementById('2409.14048v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.14048v1-abstract-full" style="display: none;"> We investigate quantum-enhanced metrology in a triple point criticality and discover that quantum criticality can not always enhance measuring precision. We have developed suitable adiabatic evolution protocols approaching a final point around the triple point to effectively restrain excitations, which could accelerate the adiabatic evolutions and lead to an exponential super-Heisenberg scaling. This scaling behavior is quite valuable in practical parameter estimating experiments with limited coherence time. The super-Heisenberg scaling will degrade into a sub-Heisenberg scaling if the adiabatic parameter modulations adopted can not reduce excitations and weaken the slowing down effect. Additionally, a feasible experimental scheme is also suggested to achieve the anticipated exponential super-Heisenberg scaling. Our findings strongly indicate that criticality-enhanced metrology can indeed significantly enhance measuring precision to a super-Heisenberg scaling when combining a triple point and beneficial parameter modulations in the adiabatic evolution, which will be conducive to the exploration of other super-Heisenberg scaling and their applications. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.14048v1-abstract-full').style.display = 'none'; document.getElementById('2409.14048v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2409.00497">arXiv:2409.00497</a> <span> [<a href="https://arxiv.org/pdf/2409.00497">pdf</a>, <a href="https://arxiv.org/format/2409.00497">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Cryptography and Security">cs.CR</span> </div> </div> <p class="title is-5 mathjax"> Security Loophole Induced by Photorefractive Effect in Continous-variable Quantum Key Distribution System </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zehao Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+P">Peng Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+T">Tao Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zeng%2C+G">Guihua Zeng</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2409.00497v1-abstract-short" style="display: inline;"> Modulators based on the Mach-Zehnder interferometer (MZI) structure are widely used in continuous-variable quantum key distribution (CVQKD) systems. MZI-based variable optical attenuator (VOA) and amplitude modulator can reshape the waveform and control the intensity of coherent state signal to realize secret key information modulation in CVQKD system. However, these devices are not ideal, interna… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.00497v1-abstract-full').style.display = 'inline'; document.getElementById('2409.00497v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.00497v1-abstract-full" style="display: none;"> Modulators based on the Mach-Zehnder interferometer (MZI) structure are widely used in continuous-variable quantum key distribution (CVQKD) systems. MZI-based variable optical attenuator (VOA) and amplitude modulator can reshape the waveform and control the intensity of coherent state signal to realize secret key information modulation in CVQKD system. However, these devices are not ideal, internal and external effects like non-linear effect and temperature may degrade their performance. In this paper, we analyzed the security loophole of CVQKD under the photorefractive effect (PE), which originates from the crystal characteristic of lithium niobate (LN). It is found that the refractive index change of modulators because of PE may lead to an overestimate or underestimate of the final secret key rate. This allows Eve to perform further attacks like intercept-resend to get more secret key information. To solve this problem, several countermeasures are proposed, which can effectively eliminate potential risks. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.00497v1-abstract-full').style.display = 'none'; document.getElementById('2409.00497v1-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 August, 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/2408.12075">arXiv:2408.12075</a> <span> [<a href="https://arxiv.org/pdf/2408.12075">pdf</a>, <a href="https://arxiv.org/format/2408.12075">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Atomic Physics">physics.atom-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.133.113204">10.1103/PhysRevLett.133.113204 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Electromagnetically-Induced-Transparency Cooling of High-Nuclear-Spin Ions </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Huang%2C+C">Chuanxin Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+C">Chenxi Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+H">Hongxuan Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Hu%2C+H">Hongyuan Hu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zuqing Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Mao%2C+Z">Zhichao Mao</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shijiao Li</a>, <a href="/search/quant-ph?searchtype=author&query=Hou%2C+P">Panyu Hou</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yukai Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zichao Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Duan%2C+L">Luming Duan</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="2408.12075v1-abstract-short" style="display: inline;"> We report the electromagnetically-induced-transparency (EIT) cooling of $^{137}\mathrm{Ba}^{+}$ ions with a nuclear spin of $I=3/2$, which are a good candidate of qubits for future large-scale trapped ion quantum computing. EIT cooling of atoms or ions with a complex ground-state level structure is challenging due to the lack of an isolated $螞$ system, as the population can escape from the $螞$ sys… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.12075v1-abstract-full').style.display = 'inline'; document.getElementById('2408.12075v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.12075v1-abstract-full" style="display: none;"> We report the electromagnetically-induced-transparency (EIT) cooling of $^{137}\mathrm{Ba}^{+}$ ions with a nuclear spin of $I=3/2$, which are a good candidate of qubits for future large-scale trapped ion quantum computing. EIT cooling of atoms or ions with a complex ground-state level structure is challenging due to the lack of an isolated $螞$ system, as the population can escape from the $螞$ system to reduce the cooling efficiency. We overcome this issue by leveraging an EIT pumping laser to repopulate the cooling subspace, ensuring continuous and effective EIT cooling. We cool the two radial modes of a single $^{137}\mathrm{Ba}^{+}$ ion to average motional occupations of 0.08(5) and 0.15(7) respectively. Using the same laser parameters, we also cool all the ten radial modes of a five-ion chain to near their ground states. Our approach can be adapted to atomic species possessing similar level structures. It allows engineering of the EIT Fano-like spectrum, which can be useful for simultaneous cooling of modes across a wide frequency range, aiding in large-scale trapped-ion quantum information processing. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.12075v1-abstract-full').style.display = 'none'; document.getElementById('2408.12075v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> PhysRevLett.133.113204 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.07552">arXiv:2408.07552</a> <span> [<a href="https://arxiv.org/pdf/2408.07552">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 key distribution based on mid-infrared and telecom band two-color entanglement source </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+W">Wu-Zhen Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+C">Chun Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Y">Yang Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+L">Li Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+R">Ren-Hui Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Han%2C+Z">Zhao-Qi-Zhi Han</a>, <a href="/search/quant-ph?searchtype=author&query=Gao%2C+M">Ming-Yuan Gao</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+X">Xiao-Hua Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zheng%2C+D">Di-Yuan Zheng</a>, <a href="/search/quant-ph?searchtype=author&query=Xie%2C+M">Meng-Yu Xie</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yin-Hai Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zhi-Yuan Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Bao%2C+W">Wan-Su Bao</a>, <a href="/search/quant-ph?searchtype=author&query=Shi%2C+B">Bao-Sen Shi</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2408.07552v1-abstract-short" style="display: inline;"> Due to the high noise caused by solar background radiation, the existing satellite-based free-space quantum key distribution (QKD) experiments are mainly carried out at night, hindering the establishment of a practical all-day real-time global-scale quantum network. Given that the 3-5 渭m mid-infrared (MIR) band has extremely low solar background radiation and strong scattering resistance, it is on… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.07552v1-abstract-full').style.display = 'inline'; document.getElementById('2408.07552v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.07552v1-abstract-full" style="display: none;"> Due to the high noise caused by solar background radiation, the existing satellite-based free-space quantum key distribution (QKD) experiments are mainly carried out at night, hindering the establishment of a practical all-day real-time global-scale quantum network. Given that the 3-5 渭m mid-infrared (MIR) band has extremely low solar background radiation and strong scattering resistance, it is one of the ideal bands for free-space quantum communication. Here, firstly, we report on the preparation of a high-quality MIR (3370 nm) and telecom band (1555 nm) two-color polarization-entangled photon source, then we use this source to realize a principle QKD based on free-space and fiber hybrid channels in a laboratory. The theoretical analysis clearly shows that a long-distance QKD over 500 km of free-space and 96 km of fiber hybrid channels can be reached simultaneously. This work represents a significant step toward developing all-day global-scale quantum communication networks. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.07552v1-abstract-full').style.display = 'none'; document.getElementById('2408.07552v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 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">24 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/2408.06317">arXiv:2408.06317</a> <span> [<a href="https://arxiv.org/pdf/2408.06317">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"> Generation of hypercubic cluster states in 1-4 dimensions in a simple optical system </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zhifan Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=de+Araujo%2C+L+E+E">Lu铆s E. E. de Araujo</a>, <a href="/search/quant-ph?searchtype=author&query=Dimario%2C+M">Matt Dimario</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+J">Jie Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Su%2C+J">Jing Su</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+M">Meng-Chang Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Anderson%2C+B+E">B. E. Anderson</a>, <a href="/search/quant-ph?searchtype=author&query=Jones%2C+K+M">Kevin M. Jones</a>, <a href="/search/quant-ph?searchtype=author&query=Lett%2C+P+D">Paul D. Lett</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="2408.06317v1-abstract-short" style="display: inline;"> Entangled graph states can be used for quantum sensing and computing applications. Error correction in measurement-based quantum computing schemes will require the construction of cluster states in at least 3 dimensions. Here we generate 1-, 2-, 3-, and 4-dimensional optical frequency-mode cluster states by sending broadband 2-mode vacuum-squeezed light through an electro-optical modulator (EOM) d… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.06317v1-abstract-full').style.display = 'inline'; document.getElementById('2408.06317v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.06317v1-abstract-full" style="display: none;"> Entangled graph states can be used for quantum sensing and computing applications. Error correction in measurement-based quantum computing schemes will require the construction of cluster states in at least 3 dimensions. Here we generate 1-, 2-, 3-, and 4-dimensional optical frequency-mode cluster states by sending broadband 2-mode vacuum-squeezed light through an electro-optical modulator (EOM) driven with multiple frequencies. We create the squeezed light using 4-wave mixing in Rb atomic vapor and mix the sideband frequencies (qumodes) using an EOM, as proposed by Zhu et al. (1), producing a pattern of entanglement correlations that constitute continuous-variable graph states containing up to several hundred qumodes. We verify the entanglement structure by using homodyne measurements to construct the covariance matrices and evaluate the nullifiers. This technique enables scaling of optical cluster states to multiple dimensions without increasing loss. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.06317v1-abstract-full').style.display = 'none'; document.getElementById('2408.06317v1-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> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.04183">arXiv:2408.04183</a> <span> [<a href="https://arxiv.org/pdf/2408.04183">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Quantum-Enhanced Polarimetric Imaging </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Xie%2C+M">Meng-Yu Xie</a>, <a href="/search/quant-ph?searchtype=author&query=Niu%2C+S">Su-Jian Niu</a>, <a href="/search/quant-ph?searchtype=author&query=Han%2C+Z">Zhao-Qi-Zhi Han</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yin-Hai Li</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+R">Ren-Hui Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+X">Xiao-Hua Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Gao%2C+M">Ming-Yuan Gao</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+L">Li Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+Y">Yue-Wei Song</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zhi-Yuan Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Shi%2C+B">Bao-Sen Shi</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2408.04183v1-abstract-short" style="display: inline;"> Polarimetric imaging, a technique that captures the invisible polarization-related properties of given materials, has broad applications from fundamental physics to advanced fields such as target recognition, stress detection, biomedical diagnosis and remote sensing. The introduction of quantum sources into classical imaging systems has demonstrated distinct advantages, yet few studies have explor… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.04183v1-abstract-full').style.display = 'inline'; document.getElementById('2408.04183v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.04183v1-abstract-full" style="display: none;"> Polarimetric imaging, a technique that captures the invisible polarization-related properties of given materials, has broad applications from fundamental physics to advanced fields such as target recognition, stress detection, biomedical diagnosis and remote sensing. The introduction of quantum sources into classical imaging systems has demonstrated distinct advantages, yet few studies have explored their combination with polarimetric imaging. In this study, we present a quantum polarimetric imaging system that integrates polarization-entangled photon pairs into a polarizer-sample-compensator-analyzer (PSRA)-type polarimeter. Our system visualizes the birefringence properties of a periodical-distributed anisotropic material under decreasing illumination levels and diverse disturbing light sources. Compared to the classical system, the quantum approach reveals the superior sensitivity and robustness in low-light conditions, particularly useful in biomedical studies where the low illumination and non-destructive detection are urgently needed. The study also highlights the nonlocality of entangled photons in birefringence measurement, indicating the potential of quantum polarimetric system in the remote sensing domain. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.04183v1-abstract-full').style.display = 'none'; document.getElementById('2408.04183v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 7 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.03801">arXiv:2408.03801</a> <span> [<a href="https://arxiv.org/pdf/2408.03801">pdf</a>, <a href="https://arxiv.org/format/2408.03801">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Hamiltonian learning for 300 trapped ion qubits with long-range couplings </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Guo%2C+S+-">S. -A. Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y+-">Y. -K. Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Ye%2C+J">J. Ye</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+L">L. Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Y">Y. Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Lian%2C+W+-">W. -Q. Lian</a>, <a href="/search/quant-ph?searchtype=author&query=Yao%2C+R">R. Yao</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+Y+-">Y. -L. Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+C">C. Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+Y+-">Y. -Z. Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Qi%2C+B+-">B. -X. Qi</a>, <a href="/search/quant-ph?searchtype=author&query=Hou%2C+P+-">P. -Y. Hou</a>, <a href="/search/quant-ph?searchtype=author&query=He%2C+L">L. He</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z+-">Z. -C. Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Duan%2C+L+-">L. -M. Duan</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="2408.03801v1-abstract-short" style="display: inline;"> Quantum simulators with hundreds of qubits and engineerable Hamiltonians have the potential to explore quantum many-body models that are intractable for classical computers. However, learning the simulated Hamiltonian, a prerequisite for any applications of a quantum simulator, remains an outstanding challenge due to the fast increasing time cost with the qubit number and the lack of high-fidelity… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.03801v1-abstract-full').style.display = 'inline'; document.getElementById('2408.03801v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.03801v1-abstract-full" style="display: none;"> Quantum simulators with hundreds of qubits and engineerable Hamiltonians have the potential to explore quantum many-body models that are intractable for classical computers. However, learning the simulated Hamiltonian, a prerequisite for any applications of a quantum simulator, remains an outstanding challenge due to the fast increasing time cost with the qubit number and the lack of high-fidelity universal gate operations in the noisy intermediate-scale quantum era. Here we demonstrate the Hamiltonian learning of a two-dimensional ion trap quantum simulator with 300 qubits. We employ global manipulations and single-qubit-resolved state detection to efficiently learn the all-to-all-coupled Ising model Hamiltonian, with the required quantum resources scaling at most linearly with the qubit number. Our work paves the way for wide applications of large-scale ion trap quantum simulators. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.03801v1-abstract-full').style.display = 'none'; document.getElementById('2408.03801v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 7 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.11809">arXiv:2407.11809</a> <span> [<a href="https://arxiv.org/pdf/2407.11809">pdf</a>, <a href="https://arxiv.org/ps/2407.11809">ps</a>, <a href="https://arxiv.org/format/2407.11809">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> </div> <p class="title is-5 mathjax"> Uhlmann quench and geometric dynamic quantum phase transition of mixed states </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Tang%2C+J">Jia-Chen Tang</a>, <a href="/search/quant-ph?searchtype=author&query=Hou%2C+X">Xu-Yang Hou</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zheng Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+H">Hao Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Chien%2C+C">Chih-Chun Chien</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="2407.11809v2-abstract-short" style="display: inline;"> Dynamic quantum phase transitions (DQPT) following quantum quenches exhibit singular behavior of the overlap between the initial and evolved states. Here we present a formalism to incorporate a geometric phase into quench dynamics of mixed quantum states, a process named the Uhlmann quench, based on the Uhlmann parallel transport. To overcome the incompatibility between the Uhlmann parallel-transp… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.11809v2-abstract-full').style.display = 'inline'; document.getElementById('2407.11809v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.11809v2-abstract-full" style="display: none;"> Dynamic quantum phase transitions (DQPT) following quantum quenches exhibit singular behavior of the overlap between the initial and evolved states. Here we present a formalism to incorporate a geometric phase into quench dynamics of mixed quantum states, a process named the Uhlmann quench, based on the Uhlmann parallel transport. To overcome the incompatibility between the Uhlmann parallel-transport condition and Hamiltonian dynamics, we formulate the evolution of purification of the density matrix in a form which not only respects the dynamics according to the density matrix but also follows the Uhlmann parallel-transport condition to generate a geometric phase after a quantum quench. For cyclic processes exemplified by a spin-1/2 system, geometric DQPTs (GDQPTs) can emerge with both singular behavior in the dynamic analogue of the free energy and jumps of the geometric phase. Moreover, the Uhlmann phase reflecting the holonomy is generated at the end of each cycle. The Uhlmann quench thus paves the way for investigating the interplay between quantum dynamics and geometric processes in mixed states. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.11809v2-abstract-full').style.display = 'none'; document.getElementById('2407.11809v2-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">v1</span> submitted 16 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">10 pages, 1 figure</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2406.13999">arXiv:2406.13999</a> <span> [<a href="https://arxiv.org/pdf/2406.13999">pdf</a>, <a href="https://arxiv.org/format/2406.13999">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"> Individually Addressed Entangling Gates in a Two-Dimensional Ion Crystal </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Hou%2C+Y+-">Y. -H. Hou</a>, <a href="/search/quant-ph?searchtype=author&query=Yi%2C+Y+-">Y. -J. Yi</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y+-">Y. -K. Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Y+-">Y. -Y. Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+L">L. Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Y">Y. Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+Y+-">Y. -L. Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+C">C. Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Mei%2C+Q+-">Q. -X. Mei</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+H+-">H. -X. Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Ma%2C+J+-">J. -Y. Ma</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+S+-">S. -A. Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Ye%2C+J">J. Ye</a>, <a href="/search/quant-ph?searchtype=author&query=Qi%2C+B+-">B. -X. Qi</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z+-">Z. -C. Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Hou%2C+P+-">P. -Y. Hou</a>, <a href="/search/quant-ph?searchtype=author&query=Duan%2C+L+-">L. -M. Duan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2406.13999v1-abstract-short" style="display: inline;"> Two-dimensional (2D) ion crystals have become a promising way to scale up qubit numbers for ion trap quantum information processing. However, to realize universal quantum computing in this system, individually addressed high-fidelity two-qubit entangling gates still remain challenging due to the inevitable micromotion of ions in a 2D crystal as well as the technical difficulty in 2D addressing. He… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.13999v1-abstract-full').style.display = 'inline'; document.getElementById('2406.13999v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2406.13999v1-abstract-full" style="display: none;"> Two-dimensional (2D) ion crystals have become a promising way to scale up qubit numbers for ion trap quantum information processing. However, to realize universal quantum computing in this system, individually addressed high-fidelity two-qubit entangling gates still remain challenging due to the inevitable micromotion of ions in a 2D crystal as well as the technical difficulty in 2D addressing. Here we demonstrate two-qubit entangling gates between any ion pairs in a 2D crystal of four ions. We use symmetrically placed crossed acousto-optic deflectors (AODs) to drive Raman transitions and achieve an addressing crosstalk error below 0.1%. We design and demonstrate a gate sequence by alternatingly addressing two target ions, making it compatible with any single-ion addressing techniques without crosstalk from multiple addressing beams. We further examine the gate performance versus the micromotion amplitude of the ions and show that its effect can be compensated by a recalibration of the laser intensity without degrading the gate fidelity. Our work paves the way for ion trap quantum computing with hundreds to thousands of qubits on a 2D ion crystal. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.13999v1-abstract-full').style.display = 'none'; document.getElementById('2406.13999v1-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 June, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2406.08251">arXiv:2406.08251</a> <span> [<a href="https://arxiv.org/pdf/2406.08251">pdf</a>, <a href="https://arxiv.org/format/2406.08251">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Atomic Physics">physics.atom-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> </div> <div 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/PhysRevResearch.6.L042002">10.1103/PhysRevResearch.6.L042002 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Light-induced fictitious magnetic fields for quantum storage in cold atomic ensembles </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wang%2C+J">Jianmin Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Dong%2C+L">Liang Dong</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+X">Xingchang Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zihan Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Zuo%2C+Y">Ying Zuo</a>, <a href="/search/quant-ph?searchtype=author&query=Siviloglou%2C+G+A">Georgios A. Siviloglou</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+J+F">J. F. Chen</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2406.08251v1-abstract-short" style="display: inline;"> In this work, we have demonstrated that optically generated fictitious magnetic fields can be utilized to extend the lifetime of quantum memories in cold atomic ensembles. All the degrees of freedom of an AC Stark shift such as polarization, spatial profile, and temporal waveform can be readily controlled in a precise manner. Temporal fluctuations over several experimental cycles, and spatial inho… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.08251v1-abstract-full').style.display = 'inline'; document.getElementById('2406.08251v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2406.08251v1-abstract-full" style="display: none;"> In this work, we have demonstrated that optically generated fictitious magnetic fields can be utilized to extend the lifetime of quantum memories in cold atomic ensembles. All the degrees of freedom of an AC Stark shift such as polarization, spatial profile, and temporal waveform can be readily controlled in a precise manner. Temporal fluctuations over several experimental cycles, and spatial inhomogeneities along a cold atomic gas have been compensated by an optical beam. The advantage of the use of fictitious magnetic fields for quantum storage stems from the speed and spatial precision that these fields can be synthesized. Our simple and versatile technique can find widespread application in coherent pulse and single-photon storage in any atomic species. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.08251v1-abstract-full').style.display = 'none'; document.getElementById('2406.08251v1-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 June, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">14pages,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/2405.16067">arXiv:2405.16067</a> <span> [<a href="https://arxiv.org/pdf/2405.16067">pdf</a>, <a href="https://arxiv.org/format/2405.16067">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"> Weaving Complex Graph on simple low-dimensional qubit lattices </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Dang%2C+Y">Yu-Hang Dang</a>, <a href="/search/quant-ph?searchtype=author&query=Dhamapurkar%2C+S">Shyam Dhamapurkar</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+X">Xiao-Long Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zheng-Yang Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Guan%2C+H">Hao-Yu Guan</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+X">Xiu-Hao Deng</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2405.16067v1-abstract-short" style="display: inline;"> In quantum computing, the connectivity of qubits placed on two-dimensional chips limits the scalability and functionality of solid-state quantum computers. This paper presents two approaches to constructing complex quantum networks from simple qubit arrays, specifically grid lattices. The first approach utilizes a subset of qubits as tunable couplers, effectively yielding a range of non-trivial gr… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.16067v1-abstract-full').style.display = 'inline'; document.getElementById('2405.16067v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.16067v1-abstract-full" style="display: none;"> In quantum computing, the connectivity of qubits placed on two-dimensional chips limits the scalability and functionality of solid-state quantum computers. This paper presents two approaches to constructing complex quantum networks from simple qubit arrays, specifically grid lattices. The first approach utilizes a subset of qubits as tunable couplers, effectively yielding a range of non-trivial graph-based Hamiltonians. The second approach employs dynamic graph engineering by periodically activating and deactivating couplers, enabling the creation of effective quantum walks with longer-range couplings. Numerical simulations verify the effective dynamics of these approaches. In terms of these two approaches, we explore implementing various graphs, including cubes and fullerenes, etc, on two-dimensional lattices. These techniques facilitate the realization of analog quantum simulation, particularly continuous-time quantum walks discussed in detail in this manuscript, for different computational tasks on superconducting quantum chips despite their inherent low dimensional simple architecture. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.16067v1-abstract-full').style.display = 'none'; document.getElementById('2405.16067v1-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 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">9 pages, 12 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2405.13369">arXiv:2405.13369</a> <span> [<a href="https://arxiv.org/pdf/2405.13369">pdf</a>, <a href="https://arxiv.org/format/2405.13369">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"> Realization of a crosstalk-free multi-ion node for long-distance quantum networking </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Lai%2C+P+-">P. -C. Lai</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Y">Y. Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Shi%2C+J+-">J. -X. Shi</a>, <a href="/search/quant-ph?searchtype=author&query=Cui%2C+Z+-">Z. -B. Cui</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z+-">Z. -Q. Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+S">S. Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+P+-">P. -Y. Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Tian%2C+Z+-">Z. -C. Tian</a>, <a href="/search/quant-ph?searchtype=author&query=Sun%2C+Y+-">Y. -D. Sun</a>, <a href="/search/quant-ph?searchtype=author&query=Chang%2C+X+-">X. -Y. Chang</a>, <a href="/search/quant-ph?searchtype=author&query=Qi%2C+B+-">B. -X. Qi</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y+-">Y. -Y. Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z+-">Z. -C. Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y+-">Y. -K. Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+Y">Y. Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Pu%2C+Y+-">Y. -F. Pu</a>, <a href="/search/quant-ph?searchtype=author&query=Duan%2C+L+-">L. -M. Duan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2405.13369v1-abstract-short" style="display: inline;"> Trapped atomic ions constitute one of the leading physical platforms for building the quantum repeater nodes to realize large-scale quantum networks. In a long-distance trapped-ion quantum network, it is essential to have crosstalk-free dual-type qubits: one type, called the communication qubit, to establish entangling interface with telecom photons; and the other type, called the memory qubit, to… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.13369v1-abstract-full').style.display = 'inline'; document.getElementById('2405.13369v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.13369v1-abstract-full" style="display: none;"> Trapped atomic ions constitute one of the leading physical platforms for building the quantum repeater nodes to realize large-scale quantum networks. In a long-distance trapped-ion quantum network, it is essential to have crosstalk-free dual-type qubits: one type, called the communication qubit, to establish entangling interface with telecom photons; and the other type, called the memory qubit, to store quantum information immune from photon scattering under entangling attempts. Here, we report the first experimental implementation of a telecom-compatible and crosstalk-free quantum network node based on two trapped $^{40}$Ca$^{+}$ ions. The memory qubit is encoded on a long-lived metastable level to avoid crosstalk with the communication qubit encoded in another subspace of the same ion species, and a quantum wavelength conversion module is employed to generate ion-photon entanglement over a $12\,$km fiber in a heralded style. Our work therefore constitutes an important step towards the realization of quantum repeaters and long-distance quantum networks. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.13369v1-abstract-full').style.display = 'none'; document.getElementById('2405.13369v1-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 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">12 pages, 12 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2405.10226">arXiv:2405.10226</a> <span> [<a href="https://arxiv.org/pdf/2405.10226">pdf</a>, <a href="https://arxiv.org/format/2405.10226">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"> Geometric phase amplification in a clock interferometer for enhanced metrology </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zhifan Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Carrasco%2C+S+C">Sebastian C. Carrasco</a>, <a href="/search/quant-ph?searchtype=author&query=Sanner%2C+C">Christian Sanner</a>, <a href="/search/quant-ph?searchtype=author&query=Malinovsky%2C+V+S">Vladimir S. Malinovsky</a>, <a href="/search/quant-ph?searchtype=author&query=Folman%2C+R">Ron Folman</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2405.10226v1-abstract-short" style="display: inline;"> High-precision measurements are crucial for testing the fundamental laws of nature and for advancing the technological frontier. Clock interferometry, where particles with an internal clock are coherently split and recombined along two spatial paths, has sparked significant interest due to its fundamental implications, especially at the intersection of quantum mechanics and general relativity. Her… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.10226v1-abstract-full').style.display = 'inline'; document.getElementById('2405.10226v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.10226v1-abstract-full" style="display: none;"> High-precision measurements are crucial for testing the fundamental laws of nature and for advancing the technological frontier. Clock interferometry, where particles with an internal clock are coherently split and recombined along two spatial paths, has sparked significant interest due to its fundamental implications, especially at the intersection of quantum mechanics and general relativity. Here, we demonstrate that a clock interferometer provides metrological improvement with respect to its technical-noise-limited counterpart employing a single internal quantum state. This enhancement around a critical working point can be interpreted as a geometric-phase-induced signal-to-noise ratio gain. In our experimental setup, we infer a precision enhancement of 8.8 decibels when measuring a small difference between external fields. We estimate that tens of decibels of precision enhancement could be attained for measurements with a higher atom flux. This opens the door to the development of a superior probe for fundamental physics as well as a high-performance sensor for various technological applications. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.10226v1-abstract-full').style.display = 'none'; document.getElementById('2405.10226v1-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 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.06944">arXiv:2403.06944</a> <span> [<a href="https://arxiv.org/pdf/2403.06944">pdf</a>, <a href="https://arxiv.org/ps/2403.06944">ps</a>, <a href="https://arxiv.org/format/2403.06944">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.110.035404">10.1103/PhysRevB.110.035404 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Sj$\ddot{\text{o}}$qvist quantum geometric tensor of finite-temperature mixed states </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zheng Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Hou%2C+X">Xu-Yang Hou</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+X">Xin Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Tang%2C+J">Jia-Chen Tang</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+H">Hao Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Chien%2C+C">Chih-Chun Chien</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2403.06944v2-abstract-short" style="display: inline;"> The quantum geometric tensor (QGT) reveals local geometric properties and associated topological information of quantum states. Here a generalization of the QGT to mixed quantum states at finite temperatures based on the Sj$\ddot{\text{o}}$qvist distance is developed. The resulting Sj$\ddot{\text{o}}$qvist QGT is invariant under gauge transformations of individual spectrum levels of the density ma… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.06944v2-abstract-full').style.display = 'inline'; document.getElementById('2403.06944v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.06944v2-abstract-full" style="display: none;"> The quantum geometric tensor (QGT) reveals local geometric properties and associated topological information of quantum states. Here a generalization of the QGT to mixed quantum states at finite temperatures based on the Sj$\ddot{\text{o}}$qvist distance is developed. The resulting Sj$\ddot{\text{o}}$qvist QGT is invariant under gauge transformations of individual spectrum levels of the density matrix. A Pythagorean-like relation connects the distances and gauge transformations, which clarifies the role of the parallel-transport condition. The real part of the QGT naturally decomposes into a sum of the Fisher-Rao metric and Fubini-Study metric, allowing a distinction between different contributions to the quantum distance. The imaginary part of the QGT is proportional to a weighted summation of the Berry curvatures, which leads to a geometric phase for mixed states under certain conditions. We present three examples of different dimensions to illustrate the temperature dependence of the QGT and a discussion on possible implications. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.06944v2-abstract-full').style.display = 'none'; document.getElementById('2403.06944v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 29 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 11 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">11 pages, 4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 110, 035404 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.06585">arXiv:2403.06585</a> <span> [<a href="https://arxiv.org/pdf/2403.06585">pdf</a>, <a href="https://arxiv.org/format/2403.06585">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevResearch.6.L032048">10.1103/PhysRevResearch.6.L032048 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Strict hierarchy of optimal strategies for global estimations: Linking global estimations with local ones </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zhao-Yi Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Qiu%2C+J">Jing-Tao Qiu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+D">Da-Jian 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="2403.06585v3-abstract-short" style="display: inline;"> A crucial yet challenging issue in quantum metrology is to ascertain the ultimate precision achievable in estimation strategies. While there are two paradigms of estimations, local and global, current research is largely confined to local estimations, which are useful once the parameter of interest is approximately known. In this Letter we target a paradigm shift towards global estimations, which… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.06585v3-abstract-full').style.display = 'inline'; document.getElementById('2403.06585v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.06585v3-abstract-full" style="display: none;"> A crucial yet challenging issue in quantum metrology is to ascertain the ultimate precision achievable in estimation strategies. While there are two paradigms of estimations, local and global, current research is largely confined to local estimations, which are useful once the parameter of interest is approximately known. In this Letter we target a paradigm shift towards global estimations, which can operate reliably even with a few measurement data and no substantial prior knowledge about the parameter. The key innovation here is to develop a technique, dubbed virtual imaginary time evolution, which establishes an equality between the information gained in a global estimation and the quantum Fisher information for a virtual local estimation. This offers an intriguing pathway to surmount challenges in the realm of global estimations by leveraging powerful tools tailored for local estimations. We explore our technique to reveal a strict hierarchy of achievable precision for different global estimation strategies and uncover unexpected results contrary to conventional wisdom in local estimations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.06585v3-abstract-full').style.display = 'none'; document.getElementById('2403.06585v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 2 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 11 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">6+18 pages. Close to the published verion</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Research 6, L032048 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.05491">arXiv:2403.05491</a> <span> [<a href="https://arxiv.org/pdf/2403.05491">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"> Slow Light Augmented Unbalanced Interferometry for Extreme Enhancement in Sensitivity of Measuring Frequency Shift in a Laser </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+R">Ruoxi Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zifan Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+J">Jinyang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Bonacum%2C+J">Jason Bonacum</a>, <a href="/search/quant-ph?searchtype=author&query=Smith%2C+D+D">David D. Smith</a>, <a href="/search/quant-ph?searchtype=author&query=Shahriar%2C+S+M">Selim M. Shahriar</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2403.05491v1-abstract-short" style="display: inline;"> We demonstrate a slow-light augmented unbalanced Mach-Zehnder interferometer (MZI) which can be used to enhance very significantly the sensitivity of measuring the frequency shift in a laser. The degree of enhancement depends on the group index of the slow-light medium, the degree of imbalance between the physical lengths of the two arms of the MZI, and the spectral width of the laser. For a laser… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.05491v1-abstract-full').style.display = 'inline'; document.getElementById('2403.05491v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.05491v1-abstract-full" style="display: none;"> We demonstrate a slow-light augmented unbalanced Mach-Zehnder interferometer (MZI) which can be used to enhance very significantly the sensitivity of measuring the frequency shift in a laser. The degree of enhancement depends on the group index of the slow-light medium, the degree of imbalance between the physical lengths of the two arms of the MZI, and the spectral width of the laser. For a laser based on a high-finesse cavity, yielding a narrow quantum noise limited spectral width, the group index has to be larger than the finesse in order to achieve enhancement in measurement sensitivity. For the reported results, strong slow-light effect is produced by employing electro-magnetically induced transparency via coherent population trapping in a buffer-gas loaded vapor cell of Rb atoms, with a maximum group index of ~1759. The observed enhancement in sensitivity for a range of group indices agrees well with the theoretical model. The maximum enhancement factor observed is ~22355, and much larger values can be obtained using cold atoms for producing the slow-light effect, for example. The sensitivity of any sensor that relies on measuring the frequency shift of a laser can be enhanced substantially using this technique. These include, but are not limited to, gyroscopes and accelerometers based on a conventional ring laser or a superluminal ring laser, and detectors for virialized ultra-light field dark matter. We also show how similar enhancements can be achieved in a slow-light augmented unbalanced Michelson interferometer. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.05491v1-abstract-full').style.display = 'none'; document.getElementById('2403.05491v1-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 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.05015">arXiv:2403.05015</a> <span> [<a href="https://arxiv.org/pdf/2403.05015">pdf</a>, <a href="https://arxiv.org/ps/2403.05015">ps</a>, <a href="https://arxiv.org/format/2403.05015">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Statistical Mechanics">cond-mat.stat-mech</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> </div> <p class="title is-5 mathjax"> Quantum Many-body Scar Models in One Dimensional Spin Chains </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wang%2C+J">Jia-Wei Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+X">Xiang-Fa Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+G">Guang-Can Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zheng-Wei 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="2403.05015v1-abstract-short" style="display: inline;"> The phenomenon of quantum many-body scars has received widespread attention both in theoretical and experimental physics in recent years due to its unique physical properties. In this paper, based on the $su(2)$ algebraic relations, we propose a general method for constructing scar models by combining simple modules.This allows us to investigate many-body scar phenomena in high-spin systems. We nu… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.05015v1-abstract-full').style.display = 'inline'; document.getElementById('2403.05015v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.05015v1-abstract-full" style="display: none;"> The phenomenon of quantum many-body scars has received widespread attention both in theoretical and experimental physics in recent years due to its unique physical properties. In this paper, based on the $su(2)$ algebraic relations, we propose a general method for constructing scar models by combining simple modules.This allows us to investigate many-body scar phenomena in high-spin systems. We numerically verify the thermalization and non-integrability of this model and demonstrate the dynamical properties of the scar states. We also provide a theoretical analysis of the properties of these scar states. For spin-$1$ case, we find that our 1D chain model reduces to the famous PXP model[C. J. Turner et al. Phys. Rev. B 98, 155134(2018)] under special parameter condition. In addition, due to the continuous tunability of the parameters, our model also enables us to investigate the transitions of QMBS from non-integrable to integrable system. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.05015v1-abstract-full').style.display = 'none'; document.getElementById('2403.05015v1-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 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">12 pages, 7 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 109, 125102 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2402.18802">arXiv:2402.18802</a> <span> [<a href="https://arxiv.org/pdf/2402.18802">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"> Narrowband telecom band polarization-entangled photon source by superposed monolithic cavities </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Gao%2C+M">Ming-Yuan Gao</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yin-Hai Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yan Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zhenghe Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+G">Guang-Can Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zhi-Yuan Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Shi%2C+B">Bao-Sen Shi</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2402.18802v1-abstract-short" style="display: inline;"> A high-quality narrowband polarization-entangled source in the telecom band is preferred to avoid frequency dispersion for long-distance transmission in optical fibers and to efficiently couple with telecom band quantum memories. Here, we report narrowband, telecom-band, polarization-entangled photon pair generation based on the superposition of single-longitudinal-mode photon pairs from two monol… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.18802v1-abstract-full').style.display = 'inline'; document.getElementById('2402.18802v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2402.18802v1-abstract-full" style="display: none;"> A high-quality narrowband polarization-entangled source in the telecom band is preferred to avoid frequency dispersion for long-distance transmission in optical fibers and to efficiently couple with telecom band quantum memories. Here, we report narrowband, telecom-band, polarization-entangled photon pair generation based on the superposition of single-longitudinal-mode photon pairs from two monolithic nonlinear crystal cavities in a passively stable interferometer based on beam displacers. The photon pairs generated from the cavities exhibit a high coincidence to accidental coincidence ratio of 20000 and a bandwidth below 500 MHz. Two-photon polarization interference, Bell-inequality, and quantum state tomography are performed to indicate the high quality of the entangled source. The current configuration demonstrates greater stability than traditional free space cavity-enhanced polarization-entangled state generation, which is promising for quantum communication applications. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.18802v1-abstract-full').style.display = 'none'; document.getElementById('2402.18802v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 28 February, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2402.18404">arXiv:2402.18404</a> <span> [<a href="https://arxiv.org/pdf/2402.18404">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> </div> </div> <p class="title is-5 mathjax"> Polarization entanglement by two simultaneous backward phase-matching processes in a single crystal </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Gao%2C+M">Ming-Yuan Gao</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yin-Hai Li</a>, <a href="/search/quant-ph?searchtype=author&query=Han%2C+Z">Zhao-Qi-Zhi Han</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Q">Qiang Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+G">Guang-Can Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zhi-Yuan Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Shi%2C+B">Bao-Sen Shi</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2402.18404v1-abstract-short" style="display: inline;"> Entanglement enables many promising applications in quantum technology. Devising new generation methods and harnessing entanglement are prerequisites for practical applications. Here we realize a distinct polarization-entangled source by simultaneously achieving type-0 and type-I backward quasi-phase matching (BQPM) through spontaneous parametric down-conversion in a single bulk crystal, which is… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.18404v1-abstract-full').style.display = 'inline'; document.getElementById('2402.18404v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2402.18404v1-abstract-full" style="display: none;"> Entanglement enables many promising applications in quantum technology. Devising new generation methods and harnessing entanglement are prerequisites for practical applications. Here we realize a distinct polarization-entangled source by simultaneously achieving type-0 and type-I backward quasi-phase matching (BQPM) through spontaneous parametric down-conversion in a single bulk crystal, which is different from all previous entangled-source configurations. Pumping the crystal with a single polarized beam generates a non-maximally polarization-entangled state, which can be further projected to a maximal Bell state with a pair of Brewster windows. Hong-Ou-Mandel interference experiments are done on polarization-degenerate photon pairs for both type-0 and type-I BQPM processes for the first time. The emitted photons in both processes have a bandwidth as narrow as 15.7 GHz. The high quality of this source is characterized by various methods. The rather simple configuration, narrow bandwidth, and high entanglement quality make the source very promising for many quantum information tasks. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.18404v1-abstract-full').style.display = 'none'; document.getElementById('2402.18404v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 28 February, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2402.17401">arXiv:2402.17401</a> <span> [<a href="https://arxiv.org/pdf/2402.17401">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> </div> </div> <p class="title is-5 mathjax"> Quantum entanglement enabled ellipsometer for phase retardance measurement </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Xie%2C+M">Meng-Yu Xie</a>, <a href="/search/quant-ph?searchtype=author&query=Niu%2C+S">Su-Jian Niu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yin-Hai Li</a>, <a href="/search/quant-ph?searchtype=author&query=Ge%2C+Z">Zheng Ge</a>, <a href="/search/quant-ph?searchtype=author&query=Gao%2C+M">Ming-Yuan Gao</a>, <a href="/search/quant-ph?searchtype=author&query=Han%2C+Z">Zhao-Qi-Zhi Han</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+R">Ren-Hui Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zhi-Yuan Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Shi%2C+B">Bao-Sen Shi</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2402.17401v1-abstract-short" style="display: inline;"> An ellipsometer is a vital precision tool used for measuring optical parameters with wide applications in many fields, including accurate measurements in film thickness, optical constants, structural profiles, etc. However, the precise measurement of photosensitive materials meets huge obstacles because of the excessive input photons, therefore the requirement of enhancing detection accuracy under… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.17401v1-abstract-full').style.display = 'inline'; document.getElementById('2402.17401v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2402.17401v1-abstract-full" style="display: none;"> An ellipsometer is a vital precision tool used for measuring optical parameters with wide applications in many fields, including accurate measurements in film thickness, optical constants, structural profiles, etc. However, the precise measurement of photosensitive materials meets huge obstacles because of the excessive input photons, therefore the requirement of enhancing detection accuracy under low incident light intensity is an essential topic in the precision measurement. In this work, by combining a polarization-entangled photon source with a classical transmission-type ellipsometer, the quantum ellipsometer with the PSA (Polarizer-Sample-Analyzer) and the Senarmount method is constructed firstly to measure the phase retardation of the birefringent materials. The experimental results show that the accuracy can reach to nanometer scale at extremely low input intensity, and the stability are within 1% for all specimens tested with a compensator involved. Our work paves the way for precision measurement at low incident light intensity, with potential applications in measuring photosensitive materials, active-biological samples and other remote monitoring scenarios. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.17401v1-abstract-full').style.display = 'none'; document.getElementById('2402.17401v1-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 February, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, 5 figures. This work has been submitted for possible publication</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2402.15090">arXiv:2402.15090</a> <span> [<a href="https://arxiv.org/pdf/2402.15090">pdf</a>, <a href="https://arxiv.org/format/2402.15090">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"> Frustration elimination for effective optical spins in coherent Ising machines </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zheng-Yang Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Gneiting%2C+C">Clemens Gneiting</a>, <a href="/search/quant-ph?searchtype=author&query=You%2C+J+Q">J. Q. You</a>, <a href="/search/quant-ph?searchtype=author&query=Nori%2C+F">Franco Nori</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2402.15090v1-abstract-short" style="display: inline;"> Frustration, that is, the impossibility to satisfy the energetic preferences between all spin pairs simultaneously, underlies the complexity of many fundamental properties in spin systems, including the computational hardness to determine their ground states. Coherent Ising machines (CIM) have been proposed as a promising analog computational approach to efficiently find different degenerate groun… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.15090v1-abstract-full').style.display = 'inline'; document.getElementById('2402.15090v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2402.15090v1-abstract-full" style="display: none;"> Frustration, that is, the impossibility to satisfy the energetic preferences between all spin pairs simultaneously, underlies the complexity of many fundamental properties in spin systems, including the computational hardness to determine their ground states. Coherent Ising machines (CIM) have been proposed as a promising analog computational approach to efficiently find different degenerate ground states of large and complex Ising models. However, CIMs also face challenges in solving frustrated Ising models: Frustration not only reduces the probability to find good solutions, but it also prohibits to leverage quantum effects in doing so. To circumvent these detrimental effects of frustration, we show how frustrated Ising models can be mapped to frustration-free CIM configurations by including ancillary modes and modifying the coupling protocol used in current CIM designs. In our proposal, degenerate optical parametric oscillator (DOPO) modes encode the ground state candidates of the studied Ising model, while the ancillary modes enable the autonomous transformation to a frustration-free Ising model that preserves the ground states encoded in the DOPO modes. Such frustration elimination may empower current CIMs to improve precision and to benefit from quantum effects in dealing with frustrated Ising models. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.15090v1-abstract-full').style.display = 'none'; document.getElementById('2402.15090v1-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 February, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">6 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/2402.07461">arXiv:2402.07461</a> <span> [<a href="https://arxiv.org/pdf/2402.07461">pdf</a>, <a href="https://arxiv.org/format/2402.07461">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Simulating the spin-boson model with a controllable reservoir in an ion trap </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wang%2C+G+-">G. -X. Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y+-">Y. -K. Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Yao%2C+R">R. Yao</a>, <a href="/search/quant-ph?searchtype=author&query=Lian%2C+W+-">W. -Q. Lian</a>, <a href="/search/quant-ph?searchtype=author&query=Cheng%2C+Z+-">Z. -J. Cheng</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+Y+-">Y. -L. Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+C">C. Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Jiang%2C+Y">Y. Jiang</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+Y+-">Y. -Z. Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Qi%2C+B+-">B. -X. Qi</a>, <a href="/search/quant-ph?searchtype=author&query=Hou%2C+P+-">P. -Y. Hou</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z+-">Z. -C. Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=He%2C+L">L. He</a>, <a href="/search/quant-ph?searchtype=author&query=Duan%2C+L+-">L. -M. Duan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2402.07461v1-abstract-short" style="display: inline;"> The spin-boson model is a prototypical model for open quantum dynamics. Here we simulate the spin-boson model using a chain of trapped ions where a spin is coupled to a structured reservoir of bosonic modes. We engineer the spectral density of the reservoir by adjusting the ion number, the target ion location, the laser detuning to the phonon sidebands, and the number of frequency components in th… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.07461v1-abstract-full').style.display = 'inline'; document.getElementById('2402.07461v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2402.07461v1-abstract-full" style="display: none;"> The spin-boson model is a prototypical model for open quantum dynamics. Here we simulate the spin-boson model using a chain of trapped ions where a spin is coupled to a structured reservoir of bosonic modes. We engineer the spectral density of the reservoir by adjusting the ion number, the target ion location, the laser detuning to the phonon sidebands, and the number of frequency components in the laser, and we observe their effects on the collapse and revival of the initially encoded information. Our work demonstrates the ion trap as a powerful platform for simulating open quantum dynamics with complicated reservoir structures. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.07461v1-abstract-full').style.display = 'none'; document.getElementById('2402.07461v1-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 February, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2401.16686">arXiv:2401.16686</a> <span> [<a href="https://arxiv.org/pdf/2401.16686">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"> Algorithm for solving a pump-probe model for an arbitrary number of energy levels </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zifan Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Sternfeld%2C+Y">Yael Sternfeld</a>, <a href="/search/quant-ph?searchtype=author&query=Scheuer%2C+J">Jacob Scheuer</a>, <a href="/search/quant-ph?searchtype=author&query=Shahriar%2C+S+M">Selim M. Shahriar</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2401.16686v1-abstract-short" style="display: inline;"> We describe a generalized algorithm for evaluating the steady-state solution of the density matrix equation of motion, for the pump-probe scheme, when two fields oscillating at different frequencies couple the same set of atomic transitions involving an arbitrary number of energy levels, to an arbitrary order of the harmonics of the pump-probe frequency difference. We developed a numerical approac… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.16686v1-abstract-full').style.display = 'inline'; document.getElementById('2401.16686v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2401.16686v1-abstract-full" style="display: none;"> We describe a generalized algorithm for evaluating the steady-state solution of the density matrix equation of motion, for the pump-probe scheme, when two fields oscillating at different frequencies couple the same set of atomic transitions involving an arbitrary number of energy levels, to an arbitrary order of the harmonics of the pump-probe frequency difference. We developed a numerical approach and a symbolic approach for this algorithm. We have verified that both approaches yield the same result for all cases studied, but require different computation time. The results are further validated by comparing them with the analytical solution of a two-level system to first order. We have also used both models to produce results up to the third order in the pump-probe frequency difference, for two-, three- and four-level systems. In addition, we have used this model to determine accurately, for the first time, the gain profile for a self-pumped Raman laser, for a system involving 16 Zeeman sublevels in the D1 manifold of 87Rb atoms. We have also used this model to determine the behavior of a single-pumped superluminal laser. In many situations involving the applications of multiple laser fields to atoms with many energy levels, one often makes the approximation that each field couples only one transition, because of the difficulty encountered in accounting for the effect of another field coupling the same transition but with a large detuning. The use of the algorithm presented here would eliminate the need for making such approximations, thus improving the accuracy of numerical calculations for such schemes. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.16686v1-abstract-full').style.display = 'none'; document.getElementById('2401.16686v1-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 January, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2401.07934">arXiv:2401.07934</a> <span> [<a href="https://arxiv.org/pdf/2401.07934">pdf</a>, <a href="https://arxiv.org/format/2401.07934">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"> Demonstration of Algorithmic Quantum Speedup for an Abelian Hidden Subgroup Problem </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Singkanipa%2C+P">P. Singkanipa</a>, <a href="/search/quant-ph?searchtype=author&query=Kasatkin%2C+V">V. Kasatkin</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Z. Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Quiroz%2C+G">G. Quiroz</a>, <a href="/search/quant-ph?searchtype=author&query=Lidar%2C+D+A">D. A. Lidar</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2401.07934v2-abstract-short" style="display: inline;"> Simon's problem is to find a hidden period (a bitstring) encoded into an unknown $2$-to-$1$ function. It is one of the earliest problems for which an exponential quantum speedup was proven for ideal, noiseless quantum computers, albeit in the oracle model. Here, using two different $127$-qubit IBM Quantum superconducting processors, we demonstrate an algorithmic quantum speedup for a variant of Si… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.07934v2-abstract-full').style.display = 'inline'; document.getElementById('2401.07934v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2401.07934v2-abstract-full" style="display: none;"> Simon's problem is to find a hidden period (a bitstring) encoded into an unknown $2$-to-$1$ function. It is one of the earliest problems for which an exponential quantum speedup was proven for ideal, noiseless quantum computers, albeit in the oracle model. Here, using two different $127$-qubit IBM Quantum superconducting processors, we demonstrate an algorithmic quantum speedup for a variant of Simon's problem where the hidden period has a restricted Hamming weight $w$. For sufficiently small values of $w$ and for circuits involving up to $58$ qubits, we demonstrate an exponential speedup, albeit of a lower quality than the speedup predicted for the noiseless algorithm. The speedup exponent and the range of $w$ values for which an exponential speedup exists are significantly enhanced when the computation is protected by dynamical decoupling. Further enhancement is achieved with measurement error mitigation. This constitutes a demonstration of a bona fide quantum advantage for an Abelian hidden subgroup problem. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.07934v2-abstract-full').style.display = 'none'; document.getElementById('2401.07934v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 23 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 15 January, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">30 pages, 29 figures, v2: significantly updated with new results and revised. The speedup result for the limited Hamming weight Simon's problem has improved from sub-exponential to exponential</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2401.07442">arXiv:2401.07442</a> <span> [<a href="https://arxiv.org/pdf/2401.07442">pdf</a>, <a href="https://arxiv.org/ps/2401.07442">ps</a>, <a href="https://arxiv.org/format/2401.07442">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Other Condensed Matter">cond-mat.other</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.109.245411">10.1103/PhysRevB.109.245411 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Interferometric Geometric Phases of $\mathcal{PT}$-symmetric Quantum Mechanics </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wang%2C+X">Xin Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zheng Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Tang%2C+J">Jia-Chen Tang</a>, <a href="/search/quant-ph?searchtype=author&query=Hou%2C+X">Xu-Yang Hou</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+H">Hao Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Chien%2C+C">Chih-Chun Chien</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2401.07442v2-abstract-short" style="display: inline;"> We present a generalization of the geometric phase to pure and thermal states in $\mathcal{PT}$-symmetric quantum mechanics (PTQM) based on the approach of the interferometric geometric phase (IGP). The formalism first introduces the parallel-transport conditions of quantum states and reveals two geometric phases, $胃^1$ and $胃^2$, for pure states in PTQM according to the states under parallel-tran… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.07442v2-abstract-full').style.display = 'inline'; document.getElementById('2401.07442v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2401.07442v2-abstract-full" style="display: none;"> We present a generalization of the geometric phase to pure and thermal states in $\mathcal{PT}$-symmetric quantum mechanics (PTQM) based on the approach of the interferometric geometric phase (IGP). The formalism first introduces the parallel-transport conditions of quantum states and reveals two geometric phases, $胃^1$ and $胃^2$, for pure states in PTQM according to the states under parallel-transport. Due to the non-Hermitian Hamiltonian in PTQM, $胃^1$ is complex and $胃^2$ is its real part. The imaginary part of $胃^1$ plays an important role when we generalize the IGP to thermal states in PTQM. The generalized IGP modifies the thermal distribution of a thermal state, thereby introducing effective temperatures. At certain critical points, the generalized IGP exhibits discrete jumps at finite temperatures, signaling a geometric phase transition. We demonstrate the finite-temperature geometric phase transition in PTQM by a two-level system and visualize its results. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.07442v2-abstract-full').style.display = 'none'; document.getElementById('2401.07442v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 17 January, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 14 January, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">12 pages, 3 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 109, 245411(2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2312.15841">arXiv:2312.15841</a> <span> [<a href="https://arxiv.org/pdf/2312.15841">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> </div> </div> <p class="title is-5 mathjax"> Strong frequency correlation and anti-correlation between a Raman laser and its pump laser for positive and negative dispersions </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zifan Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+R">Ruoxi Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Shahriar%2C+S+M">Selim M. Shahriar</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2312.15841v1-abstract-short" style="display: inline;"> We show that the frequency of a Raman laser is highly correlated or anti-correlated with the frequency of the Raman pump laser, depending on whether the dispersion experienced by the Raman laser is positive or negative. For a subluminal laser, corresponding to a positive dispersion with a group index that is much larger than unity, the shift in its frequency is approximately the same as that in th… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.15841v1-abstract-full').style.display = 'inline'; document.getElementById('2312.15841v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2312.15841v1-abstract-full" style="display: none;"> We show that the frequency of a Raman laser is highly correlated or anti-correlated with the frequency of the Raman pump laser, depending on whether the dispersion experienced by the Raman laser is positive or negative. For a subluminal laser, corresponding to a positive dispersion with a group index that is much larger than unity, the shift in its frequency is approximately the same as that in the Raman pump laser. In contrast, for a superluminal laser, corresponding to a negative dispersion with a group index that is close to zero, its frequency shifts in the direction opposite to that of the Raman pump lasers, and has an amplitude that is larger by a factor approximately equaling the inverse of the group index. These findings would play a critical role in determining the maximum achievable sensitivity of sensors employing such lasers, especially under conditions where the pump laser linewidth is broadened significantly beyond the Schawlow-Townes linewidth due to classical fluctuations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.15841v1-abstract-full').style.display = 'none'; document.getElementById('2312.15841v1-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 December, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">28 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/2311.17588">arXiv:2311.17588</a> <span> [<a href="https://arxiv.org/pdf/2311.17588">pdf</a>, <a href="https://arxiv.org/format/2311.17588">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"> Realization of edge states along a synthetic orbital angular momentum dimension </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Liao%2C+Y">Yu-Wei Liao</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+M">Mu Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+H">Hao-Qing Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Hao%2C+Z">Zhi-He Hao</a>, <a href="/search/quant-ph?searchtype=author&query=Hu%2C+J">Jun Hu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+T">Tian-Xiang Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zong-Quan Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Luo%2C+X">Xi-Wang Luo</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+J">Jin-Shi Xu</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="2311.17588v1-abstract-short" style="display: inline;"> The synthetic dimension is a rising method to study topological physics, which enables us to implement high-dimensional physics in low-dimensional geometries. Photonic orbital angular momentum (OAM), a degree of freedom characterized by discrete yet unbounded, serves as a suitable synthetic dimension. However, a sharp boundary along a synthetic OAM dimension has not been demonstrated, dramatically… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.17588v1-abstract-full').style.display = 'inline'; document.getElementById('2311.17588v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2311.17588v1-abstract-full" style="display: none;"> The synthetic dimension is a rising method to study topological physics, which enables us to implement high-dimensional physics in low-dimensional geometries. Photonic orbital angular momentum (OAM), a degree of freedom characterized by discrete yet unbounded, serves as a suitable synthetic dimension. However, a sharp boundary along a synthetic OAM dimension has not been demonstrated, dramatically limiting the investigation of topological edge effects in an open boundary lattice system. In this work, we make a sharp boundary along a Floquet Su-Schrieffer-Heeger OAM lattice and form approximate semi-infinite lattices by drilling a pinhole on the optical elements in a cavity. The band structures with zero ($\pm蟺$) energy boundary states are measured directly, benefiting from the spectra detection of the cavity. Moreover, we obtain the edge modes moving from the gap to the bulk by dynamically changing the boundary phase, and we reveal that interference near the surface leads to spectrum discretization. Our work provides a new perspective to observe edge effects and explore practical photonics tools. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.17588v1-abstract-full').style.display = 'none'; document.getElementById('2311.17588v1-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 November, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2023. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2311.17163">arXiv:2311.17163</a> <span> [<a href="https://arxiv.org/pdf/2311.17163">pdf</a>, <a href="https://arxiv.org/format/2311.17163">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 Site-Resolved 2D Quantum Simulator with Hundreds of Trapped Ions </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Guo%2C+S+-">S. -A. Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y+-">Y. -K. Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Ye%2C+J">J. Ye</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+L">L. Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Lian%2C+W+-">W. -Q. Lian</a>, <a href="/search/quant-ph?searchtype=author&query=Yao%2C+R">R. Yao</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Y">Y. Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Yan%2C+R+-">R. -Y. Yan</a>, <a href="/search/quant-ph?searchtype=author&query=Yi%2C+Y+-">Y. -J. Yi</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+Y+-">Y. -L. Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+B+-">B. -W. Li</a>, <a href="/search/quant-ph?searchtype=author&query=Hou%2C+Y+-">Y. -H. Hou</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+Y+-">Y. -Z. Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+W+-">W. -X. Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+C">C. Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Qi%2C+B+-">B. -X. Qi</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z+-">Z. -C. Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=He%2C+L">L. He</a>, <a href="/search/quant-ph?searchtype=author&query=Duan%2C+L+-">L. -M. Duan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2311.17163v2-abstract-short" style="display: inline;"> A large qubit capacity and an individual readout capability are two crucial requirements for large-scale quantum computing and simulation. As one of the leading physical platforms for quantum information processing, the ion trap has achieved quantum simulation of tens of ions with site-resolved readout in 1D Paul trap, and that of hundreds of ions with global observables in 2D Penning trap. Howeve… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.17163v2-abstract-full').style.display = 'inline'; document.getElementById('2311.17163v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2311.17163v2-abstract-full" style="display: none;"> A large qubit capacity and an individual readout capability are two crucial requirements for large-scale quantum computing and simulation. As one of the leading physical platforms for quantum information processing, the ion trap has achieved quantum simulation of tens of ions with site-resolved readout in 1D Paul trap, and that of hundreds of ions with global observables in 2D Penning trap. However, integrating these two features into a single system is still very challenging. Here we report the stable trapping of 512 ions in a 2D Wigner crystal and the sideband cooling of their transverse motion. We demonstrate the quantum simulation of long-range quantum Ising models with tunable coupling strengths and patterns, with or without frustration, using 300 ions. Enabled by the site resolution in the single-shot measurement, we observe rich spatial correlation patterns in the quasi-adiabatically prepared ground states, which allows us to verify quantum simulation results by comparing with the calculated collective phonon modes and with classical simulated annealing. We further probe the quench dynamics of the Ising model in a transverse field to demonstrate quantum sampling tasks. Our work paves the way for simulating classically intractable quantum dynamics and for running NISQ algorithms using 2D ion trap quantum simulators. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.17163v2-abstract-full').style.display = 'none'; document.getElementById('2311.17163v2-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 April, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 28 November, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2023. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2311.12444">arXiv:2311.12444</a> <span> [<a href="https://arxiv.org/pdf/2311.12444">pdf</a>, <a href="https://arxiv.org/ps/2311.12444">ps</a>, <a href="https://arxiv.org/format/2311.12444">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Computer Science and Game Theory">cs.GT</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Quantum Communication Complexity of Classical Auctions </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Rubinstein%2C+A">Aviad Rubinstein</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zixin 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="2311.12444v1-abstract-short" style="display: inline;"> We study the fundamental, classical mechanism design problem of single-buyer multi-item Bayesian revenue-maximizing auctions under the lens of communication complexity between the buyer and the seller. Specifically, we ask whether using quantum communication can be more efficient than classical communication. We have two sets of results, revealing a surprisingly rich landscape - which looks quite… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.12444v1-abstract-full').style.display = 'inline'; document.getElementById('2311.12444v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2311.12444v1-abstract-full" style="display: none;"> We study the fundamental, classical mechanism design problem of single-buyer multi-item Bayesian revenue-maximizing auctions under the lens of communication complexity between the buyer and the seller. Specifically, we ask whether using quantum communication can be more efficient than classical communication. We have two sets of results, revealing a surprisingly rich landscape - which looks quite different from both quantum communication in non-strategic parties, and classical communication in mechanism design. We first study the expected communication complexity of approximately optimal auctions. We give quantum auction protocols for buyers with unit-demand or combinatorial valuations that obtain an arbitrarily good approximation of the optimal revenue while running in exponentially more efficient communication compared to classical approximately optimal auctions. However, these auctions come with the caveat that they may require the seller to charge exponentially large payments from a deviating buyer. We show that this caveat is necessary - we give an exponential lower bound on the product of the expected quantum communication and the maximum payment. We then study the worst-case communication complexity of exactly optimal auctions in an extremely simple setting: additive buyer's valuations over two items. We show the following separations: 1. There exists a prior where the optimal classical auction protocol requires infinitely many bits, but a one-way message of 1 qubit and 2 classical bits suffices. 2. There exists a prior where no finite one-way quantum auction protocol can obtain the optimal revenue. However, there is a barely-interactive revenue-optimal quantum auction protocol. 3. There exists a prior where no multi-round quantum auction protocol with a finite bound on communication complexity can obtain the optimal revenue. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.12444v1-abstract-full').style.display = 'none'; document.getElementById('2311.12444v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 November, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2023. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2311.12017">arXiv:2311.12017</a> <span> [<a href="https://arxiv.org/pdf/2311.12017">pdf</a>, <a href="https://arxiv.org/format/2311.12017">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Computational Complexity">cs.CC</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Cryptography and Security">cs.CR</span> </div> </div> <p class="title is-5 mathjax"> Public-key pseudoentanglement and the hardness of learning ground state entanglement structure </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Bouland%2C+A">Adam Bouland</a>, <a href="/search/quant-ph?searchtype=author&query=Fefferman%2C+B">Bill Fefferman</a>, <a href="/search/quant-ph?searchtype=author&query=Ghosh%2C+S">Soumik Ghosh</a>, <a href="/search/quant-ph?searchtype=author&query=Metger%2C+T">Tony Metger</a>, <a href="/search/quant-ph?searchtype=author&query=Vazirani%2C+U">Umesh Vazirani</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+C">Chenyi Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zixin 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="2311.12017v1-abstract-short" style="display: inline;"> Given a local Hamiltonian, how difficult is it to determine the entanglement structure of its ground state? We show that this problem is computationally intractable even if one is only trying to decide if the ground state is volume-law vs near area-law entangled. We prove this by constructing strong forms of pseudoentanglement in a public-key setting, where the circuits used to prepare the states… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.12017v1-abstract-full').style.display = 'inline'; document.getElementById('2311.12017v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2311.12017v1-abstract-full" style="display: none;"> Given a local Hamiltonian, how difficult is it to determine the entanglement structure of its ground state? We show that this problem is computationally intractable even if one is only trying to decide if the ground state is volume-law vs near area-law entangled. We prove this by constructing strong forms of pseudoentanglement in a public-key setting, where the circuits used to prepare the states are public knowledge. In particular, we construct two families of quantum circuits which produce volume-law vs near area-law entangled states, but nonetheless the classical descriptions of the circuits are indistinguishable under the Learning with Errors (LWE) assumption. Indistinguishability of the circuits then allows us to translate our construction to Hamiltonians. Our work opens new directions in Hamiltonian complexity, for example whether it is difficult to learn certain phases of matter. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.12017v1-abstract-full').style.display = 'none'; document.getElementById('2311.12017v1-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, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">58 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/2311.08733">arXiv:2311.08733</a> <span> [<a href="https://arxiv.org/pdf/2311.08733">pdf</a>, <a href="https://arxiv.org/format/2311.08733">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="Optics">physics.optics</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Plasma Physics">physics.plasm-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"> Topological States Decorated by Twig Boundary in Plasma Photonic Crystals </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+J">Jianfei Li</a>, <a href="/search/quant-ph?searchtype=author&query=Yao%2C+J">Jingfeng Yao</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Y">Ying Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zhongxiang Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Lan%2C+Z">Zhihao Lan</a>, <a href="/search/quant-ph?searchtype=author&query=Yuan%2C+C">Chengxun Yuan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2311.08733v2-abstract-short" style="display: inline;"> The twig edge states in graphene-like structures are viewed as the fourth states complementary to their zigzag, bearded, and armchair counterparts. In this work, we study a rod-in-plasma system in honeycomb lattice with twig edge truncation under external magnetic fields and lattice scaling and show that twig edge states can exist in different phases of the system, such as quantum Hall phase, quan… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.08733v2-abstract-full').style.display = 'inline'; document.getElementById('2311.08733v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2311.08733v2-abstract-full" style="display: none;"> The twig edge states in graphene-like structures are viewed as the fourth states complementary to their zigzag, bearded, and armchair counterparts. In this work, we study a rod-in-plasma system in honeycomb lattice with twig edge truncation under external magnetic fields and lattice scaling and show that twig edge states can exist in different phases of the system, such as quantum Hall phase, quantum spin Hall phase and insulating phase. The twig edge states in the negative permittivity background exhibit robust one-way transmission property immune to backscattering and thus provide a novel avenue for solving the plasma communication blackout problem. Moreover, we demonstrate that corner and edge states can exist within the shrunken structure by modulating the on-site potential of the twig edges. Especially, helical edge states with the unique feature of pseudospin-momentum locking that could be excited by chiral sources are demonstrated at the twig edges. Our results show that the twig edges and interface engineering can bring new opportunities for more flexible manipulation of electromagnetic waves. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.08733v2-abstract-full').style.display = 'none'; document.getElementById('2311.08733v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 April, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 15 November, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2023. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2311.07203">arXiv:2311.07203</a> <span> [<a href="https://arxiv.org/pdf/2311.07203">pdf</a>, <a href="https://arxiv.org/format/2311.07203">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="Optics">physics.optics</span> </div> </div> <p class="title is-5 mathjax"> Optical Quantum Sensing for Agnostic Environments via Deep Learning </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zeqiao Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Du%2C+Y">Yuxuan Du</a>, <a href="/search/quant-ph?searchtype=author&query=Yin%2C+X">Xu-Fei Yin</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+S">Shanshan Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Tian%2C+X">Xinmei Tian</a>, <a href="/search/quant-ph?searchtype=author&query=Tao%2C+D">Dacheng Tao</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2311.07203v1-abstract-short" style="display: inline;"> Optical quantum sensing promises measurement precision beyond classical sensors termed the Heisenberg limit (HL). However, conventional methodologies often rely on prior knowledge of the target system to achieve HL, presenting challenges in practical applications. Addressing this limitation, we introduce an innovative Deep Learning-based Quantum Sensing scheme (DQS), enabling optical quantum senso… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.07203v1-abstract-full').style.display = 'inline'; document.getElementById('2311.07203v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2311.07203v1-abstract-full" style="display: none;"> Optical quantum sensing promises measurement precision beyond classical sensors termed the Heisenberg limit (HL). However, conventional methodologies often rely on prior knowledge of the target system to achieve HL, presenting challenges in practical applications. Addressing this limitation, we introduce an innovative Deep Learning-based Quantum Sensing scheme (DQS), enabling optical quantum sensors to attain HL in agnostic environments. DQS incorporates two essential components: a Graph Neural Network (GNN) predictor and a trigonometric interpolation algorithm. Operating within a data-driven paradigm, DQS utilizes the GNN predictor, trained on offline data, to unveil the intrinsic relationships between the optical setups employed in preparing the probe state and the resulting quantum Fisher information (QFI) after interaction with the agnostic environment. This distilled knowledge facilitates the identification of optimal optical setups associated with maximal QFI. Subsequently, DQS employs a trigonometric interpolation algorithm to recover the unknown parameter estimates for the identified optical setups. Extensive experiments are conducted to investigate the performance of DQS under different settings up to eight photons. Our findings not only offer a new lens through which to accelerate optical quantum sensing tasks but also catalyze future research integrating deep learning and quantum mechanics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.07203v1-abstract-full').style.display = 'none'; document.getElementById('2311.07203v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 13 November, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2023. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2311.00503">arXiv:2311.00503</a> <span> [<a href="https://arxiv.org/pdf/2311.00503">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Medical Physics">physics.med-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"> Ray computational ghost imaging based on rotational modulation method </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zhi Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Sangang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Liao%2C+S">Shan Liao</a>, <a href="/search/quant-ph?searchtype=author&query=Gong%2C+S">Sirun Gong</a>, <a href="/search/quant-ph?searchtype=author&query=Su%2C+R">Rongrong Su</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+C">Chuxiang Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+L">Li Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+Q">Qi Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Yan%2C+Y">Yucheng Yan</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+M">Mingzhe Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Cheng%2C+Y">Yi Cheng</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2311.00503v1-abstract-short" style="display: inline;"> The CGI (CGI) has the potential of low cost, low dose, and high resolution, which is very attractive for the development of radiation imaging field. However, many sub-coding plates must be used in the modulation process, which greatly affects the development of CGI technology. In order to reduce the coding plates, we refer to the rotation method of computed tomography (CT), then propose a novel CG… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.00503v1-abstract-full').style.display = 'inline'; document.getElementById('2311.00503v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2311.00503v1-abstract-full" style="display: none;"> The CGI (CGI) has the potential of low cost, low dose, and high resolution, which is very attractive for the development of radiation imaging field. However, many sub-coding plates must be used in the modulation process, which greatly affects the development of CGI technology. In order to reduce the coding plates, we refer to the rotation method of computed tomography (CT), then propose a novel CGI method based on rotational modulation method of a single-column striped coding plate. This method utilizes the spatial variation of a single sub-coding plate (rotation) to realize multiple modulation of the ray field and improves the utilization rate of a single sub-coding plate. However, for this rotation scheme of CGI, the traditional binary modulation matrix is no longer applicable. To obtain the system matrix of the rotated striped coding plate, an area model based on beam boundaries is established. Subsequently, numerical and Monte Carlo simulations were conducted. The results reveal that our scheme enables high-quality imaging of N*N resolution objects using only N sub-coding plates, under both full-sampling and under-sampling scenarios. Moreover, our scheme demonstrates superiority over the Hadamard scheme in both imaging quality and the number of required sub-coding plates, whether in scenarios of full-sampling or under-sampling. Finally, an 伪 ray imaging platform was established to further demonstrate the feasibility of the rotational modulation method. By employing our scheme, a mere 8 sub-coding plates were employed to achieve CGI of the radiation source intensity distribution, achieving a resolution of 8*8. Therefore, the novel ray CGI based on rotational modulation method can achieve high-quality imaging effect with fewer sub-coding plates, which has important practical value and research significance for promoting single-pixel radiation imaging technology. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.00503v1-abstract-full').style.display = 'none'; document.getElementById('2311.00503v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 1 November, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2023. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2310.14937">arXiv:2310.14937</a> <span> [<a href="https://arxiv.org/pdf/2310.14937">pdf</a>, <a href="https://arxiv.org/ps/2310.14937">ps</a>, <a href="https://arxiv.org/format/2310.14937">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Phenomenology">hep-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mathematical Physics">math-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Nuclear Theory">nucl-th</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"> On the generalized Friedrichs-Lee model with multiple discrete and continuous states </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Xiao%2C+Z">Zhiguang Xiao</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zhi-Yong 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="2310.14937v1-abstract-short" style="display: inline;"> In this study, we present several improvements of the non-relativistic Friedrichs-Lee model with multiple discrete and continuous states and still retain its solvability. Our findings establish a solid theoretical basis for the exploration of resonance phenomena in scenarios involving the presence of multiple interfering states across various channels. The scattering amplitudes associated with the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.14937v1-abstract-full').style.display = 'inline'; document.getElementById('2310.14937v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2310.14937v1-abstract-full" style="display: none;"> In this study, we present several improvements of the non-relativistic Friedrichs-Lee model with multiple discrete and continuous states and still retain its solvability. Our findings establish a solid theoretical basis for the exploration of resonance phenomena in scenarios involving the presence of multiple interfering states across various channels. The scattering amplitudes associated with the continuous states naturally adhere to coupled-channel unitarity, rendering this framework particularly valuable for investigating hadronic resonant states appearing in multiple coupled channels. Moreover, this generalized framework exhibits a wide-range applicability, enabling investigations into resonance phenomena across diverse physical domains, including hadron physics, nuclear physics, optics, and cold atom physics, among others. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.14937v1-abstract-full').style.display = 'none'; document.getElementById('2310.14937v1-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 October, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">25 pages, 2 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2310.11900">arXiv:2310.11900</a> <span> [<a href="https://arxiv.org/pdf/2310.11900">pdf</a>, <a href="https://arxiv.org/format/2310.11900">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Atomic Physics">physics.atom-ph</span> </div> </div> <p class="title is-5 mathjax"> Properties of Two-Mode Quadrature Squeezing from Four-wave Mixing in Rubidium Vapor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=De+Araujo%2C+L+E+E">Lu脥s E. E. De Araujo</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zhifan Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Dimario%2C+M">Matt Dimario</a>, <a href="/search/quant-ph?searchtype=author&query=Anderson%2C+B+E">B. E. Anderson</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+J">Jie Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Jones%2C+K+M">Kevin M. Jones</a>, <a href="/search/quant-ph?searchtype=author&query=Lett%2C+P+D">Paul D. Lett</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2310.11900v1-abstract-short" style="display: inline;"> We present a study of homodyne measurements of two-mode, vacuum-seeded, quadrature-squeezed light generated by four-wave mixing in warm rubidium vapor. Our results reveal that the vacuum squeezing can extend down to measurement frequencies of less than 1 Hz, and the squeezing bandwidth, similar to the seeded intensity-difference squeezing measured in this system, reaches up to approximately 20 MHz… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.11900v1-abstract-full').style.display = 'inline'; document.getElementById('2310.11900v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2310.11900v1-abstract-full" style="display: none;"> We present a study of homodyne measurements of two-mode, vacuum-seeded, quadrature-squeezed light generated by four-wave mixing in warm rubidium vapor. Our results reveal that the vacuum squeezing can extend down to measurement frequencies of less than 1 Hz, and the squeezing bandwidth, similar to the seeded intensity-difference squeezing measured in this system, reaches up to approximately 20 MHz for typical pump parameters. By dividing the squeezing bandwidth into smaller frequency bins, we show that different sideband frequencies represent independent sources of two-mode squeezing. Such frequency bins may provide useful qumodes for quantum information processing experiments. We also investigate the impact of group velocity delays on the correlations in the system. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.11900v1-abstract-full').style.display = 'none'; document.getElementById('2310.11900v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 October, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2023. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2310.08730">arXiv:2310.08730</a> <span> [<a href="https://arxiv.org/pdf/2310.08730">pdf</a>, <a href="https://arxiv.org/format/2310.08730">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"> On the nature of two-photon transitions for a Collection of Molecules in a Fabry-Perot Cavity </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zeyu Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+H">Hsing-Ta Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Sukharev%2C+M">Maxim Sukharev</a>, <a href="/search/quant-ph?searchtype=author&query=Subotnik%2C+J+E">Joseph E. Subotnik</a>, <a href="/search/quant-ph?searchtype=author&query=Nitzan%2C+A">Abraham Nitzan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2310.08730v1-abstract-short" style="display: inline;"> We investigate the effect of a cavity on nonlinear two-photon transitions of a molecular system and how such an effect depends on the cavity quality factor, the field enhancement and the possibility of dephasing. We find that the molecular response to strong light fields in a cavity with variable quality factor can be understood as arising from a balance between (i) the ability of the cavity to en… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.08730v1-abstract-full').style.display = 'inline'; document.getElementById('2310.08730v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2310.08730v1-abstract-full" style="display: none;"> We investigate the effect of a cavity on nonlinear two-photon transitions of a molecular system and how such an effect depends on the cavity quality factor, the field enhancement and the possibility of dephasing. We find that the molecular response to strong light fields in a cavity with variable quality factor can be understood as arising from a balance between (i) the ability of the cavity to enhance the field of an external probe and promote multiphoton transitions more easily and (ii) the fact that the strict selection rules on multiphoton transitions in a cavity support only one resonant frequency within the excitation range. Although our simulations use a classical-level description of the radiation field (i.e. we solve Maxwell-Bloch or Maxwell-Liouville equations within the Ehrenfest approximation for the field-molecule interaction), based on experience with this level of approximation in past studies of plasmonic and polaritonic systems, we believe that our results are valid over a wide range of external probing. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.08730v1-abstract-full').style.display = 'none'; document.getElementById('2310.08730v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 October, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">19 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/2309.08890">arXiv:2309.08890</a> <span> [<a href="https://arxiv.org/pdf/2309.08890">pdf</a>, <a href="https://arxiv.org/ps/2309.08890">ps</a>, <a href="https://arxiv.org/format/2309.08890">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Statistical Mechanics">cond-mat.stat-mech</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1021/acs.jctc.3c01099">10.1021/acs.jctc.3c01099 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Stochastic Schr枚dinger equation approach to real-time dynamics of Anderson-Holstein impurities: an open quantum system perspective </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Z">Zhen Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+L">Limin Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zhennan 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="2309.08890v1-abstract-short" style="display: inline;"> We develop a stochastic Schr枚dinger equation (SSE) framework to simulate real-time dynamics of Anderson-Holstein (AH) impurities coupled to a continuous fermionic bath. The bath degrees of freedom are incorporated through fluctuating terms determined by exact system-bath correlations, which is derived in an ab initio manner. We show that such an SSE treatment provides a middle ground between numer… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.08890v1-abstract-full').style.display = 'inline'; document.getElementById('2309.08890v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2309.08890v1-abstract-full" style="display: none;"> We develop a stochastic Schr枚dinger equation (SSE) framework to simulate real-time dynamics of Anderson-Holstein (AH) impurities coupled to a continuous fermionic bath. The bath degrees of freedom are incorporated through fluctuating terms determined by exact system-bath correlations, which is derived in an ab initio manner. We show that such an SSE treatment provides a middle ground between numerically expansive microscopic simulations and macroscopic master equations. Computationally, the SSE model enables efficient numerical methods for propagating stochastic trajectories. We demonstrate that this approach not only naturally provides microscopically-detailed information unavailable from reduced models, but also captures effects beyond master equations, thus serves as a promising tool to study open quantum dynamics emerging in physics and chemistry. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.08890v1-abstract-full').style.display = 'none'; document.getElementById('2309.08890v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 September, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">16 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/2309.05188">arXiv:2309.05188</a> <span> [<a href="https://arxiv.org/pdf/2309.05188">pdf</a>, <a href="https://arxiv.org/ps/2309.05188">ps</a>, <a href="https://arxiv.org/format/2309.05188">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mathematical Physics">math-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Numerical Analysis">math.NA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Probability">math.PR</span> </div> </div> <p class="title is-5 mathjax"> Quantitative Convergence Analysis of Path Integral Representations for Quantum Thermal Average </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Ye%2C+X">Xuda Ye</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zhennan 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="2309.05188v1-abstract-short" style="display: inline;"> The quantum thermal average is a central topic in quantum physics and can be represented by the path integrals. For the computational perspective, the path integral representation (PIR) needs to be approximated in a finite-dimensional space, and the convergence of such approximation is termed as the convergence of the PIR. In this paper, we establish the Trotter product formula in the trace form,… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.05188v1-abstract-full').style.display = 'inline'; document.getElementById('2309.05188v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2309.05188v1-abstract-full" style="display: none;"> The quantum thermal average is a central topic in quantum physics and can be represented by the path integrals. For the computational perspective, the path integral representation (PIR) needs to be approximated in a finite-dimensional space, and the convergence of such approximation is termed as the convergence of the PIR. In this paper, we establish the Trotter product formula in the trace form, which connects the quantum thermal average and the Boltzmann distribution of a continuous loop in a rigorous way. We prove the qualitative convergence of the standard PIR, and obtain the explicit convergence rates of the continuous loop PIR. These results showcase various approaches to approximate the quantum thermal average, which provide theoretical guarantee for the path integral approaches of quantum thermal equilibrium systems, such as the path integral molecular dynamics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.05188v1-abstract-full').style.display = 'none'; document.getElementById('2309.05188v1-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, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">MSC Class:</span> 82B31; 81S40 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2309.03663">arXiv:2309.03663</a> <span> [<a href="https://arxiv.org/pdf/2309.03663">pdf</a>, <a href="https://arxiv.org/ps/2309.03663">ps</a>, <a href="https://arxiv.org/format/2309.03663">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> </div> <p class="title is-5 mathjax"> Interaction between giant atoms in a one-dimensional topological waveguide </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wang%2C+D">Da-Wei Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+C">Chengsong Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+J">Junya Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Yan%2C+Y">Ye-Ting Yan</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z+L">Zhihai-Wang Ling 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="2309.03663v2-abstract-short" style="display: inline;"> In this paper, we consider giant atoms coupled to a one-dimensional topological waveguide reservoir. We studied the following two cases. In the bandgap regime, where the giant-atom frequency lies outside the band, we study the generation and distribution of giant atom-photon bound states and the difference between the topological waveguide in topological and trivial phases. When the strengths of… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.03663v2-abstract-full').style.display = 'inline'; document.getElementById('2309.03663v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2309.03663v2-abstract-full" style="display: none;"> In this paper, we consider giant atoms coupled to a one-dimensional topological waveguide reservoir. We studied the following two cases. In the bandgap regime, where the giant-atom frequency lies outside the band, we study the generation and distribution of giant atom-photon bound states and the difference between the topological waveguide in topological and trivial phases. When the strengths of the giant atoms coupled to the two sub-lattice points are equal, the photons distribution is symmetrical and the chiral photon distribution is exhibited when the coupling is different. The coherent interactions between giant atoms are induced by virtual photons, or can be understood as an overlap of photon bound-state wave functions, and decay exponentially with increasing distance between the giant atoms. We also find that the coherent interactions induced by the topological phase are larger than those induced by the trivial phase for the same bandgap width. In the band regime, the giant-atom frequency lies in the band, under the Born-Markov approximation, we obtained effective coherence and correlated dissipative interactions between the giant atoms mediated by topological waveguide reservoirs, which depend on the giant-atom coupling nodes. We analyze the effect of the form of the giant-atom coupling point on the decay, and on the associated dissipation. The results show that we can design the coupling form as well as the frequency of the giant atoms to achieve zero decay and correlation dissipation and non-zero coherent interactions. Finally we used this scheme to realize the excitation transfer of giant atoms. Our work will promote the study of topological matter coupled to giant atoms. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.03663v2-abstract-full').style.display = 'none'; document.getElementById('2309.03663v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 November, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 7 September, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2023. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2308.11823">arXiv:2308.11823</a> <span> [<a href="https://arxiv.org/pdf/2308.11823">pdf</a>, <a href="https://arxiv.org/format/2308.11823">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Gases">cond-mat.quant-gas</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.109.245107">10.1103/PhysRevB.109.245107 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Solving Fermi-Hubbard-type Models by Tensor Representations of Backflow Corrections </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Y">Yu-Tong Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zheng-Wei Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Liang%2C+X">Xiao Liang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2308.11823v6-abstract-short" style="display: inline;"> The quantum many-body problem is an important topic in condensed matter physics. To efficiently solve the problem, several methods have been developped to improve the representation ability of wave-functions. For the Fermi-Hubbard model under periodic boundary conditions, current state-of-the-art methods are neural network backflows and the hidden fermion Slater determinant. The backflow corre… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.11823v6-abstract-full').style.display = 'inline'; document.getElementById('2308.11823v6-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2308.11823v6-abstract-full" style="display: none;"> The quantum many-body problem is an important topic in condensed matter physics. To efficiently solve the problem, several methods have been developped to improve the representation ability of wave-functions. For the Fermi-Hubbard model under periodic boundary conditions, current state-of-the-art methods are neural network backflows and the hidden fermion Slater determinant. The backflow correction is an efficient way to improve the Slater determinant of free-particles. In this work we propose a tensor representation of the backflow corrected wave-function, we show that for the spinless $t$-$V$ model, the energy precision is competitive or even lower than current state-of-the-art fermionic tensor network methods. For models with spin, we further improve the representation ability by considering backflows on fictitious particles with different spins, thus naturally introducing non-zero backflow corrections when the orbital and the particle have opposite spins. We benchmark our method on molecules under STO-3G basis and the Fermi-Hubbard model with periodic and cylindrical boudary conditions. We show that the tensor representation of backflow corrections achieves competitive or even lower energy results than current state-of-the-art neural network methods. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.11823v6-abstract-full').style.display = 'none'; document.getElementById('2308.11823v6-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 20 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 22 August, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">9 pages, 6 figures, comments are welcome</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 109, 245107 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2308.10165">arXiv:2308.10165</a> <span> [<a href="https://arxiv.org/pdf/2308.10165">pdf</a>, <a href="https://arxiv.org/format/2308.10165">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"> Counterfactual communication without a trace in the transmission channel </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Pan%2C+W">Wei-Wei Pan</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+X">Xiao Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+X">Xiao-Ye Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Q">Qin-Qin Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Cheng%2C+Z">Ze-Di Cheng</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+J">Jian Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+Z">Zhao-Di Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+G">Geng Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zong-Quan Zhou</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>, <a href="/search/quant-ph?searchtype=author&query=Dressel%2C+J">Justin Dressel</a>, <a href="/search/quant-ph?searchtype=author&query=Vaidman%2C+L">Lev Vaidman</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2308.10165v1-abstract-short" style="display: inline;"> We report an experimental realization of a modified counterfactual communication protocol that eliminates the dominant environmental trace left by photons passing through the transmission channel. Compared to Wheeler's criterion for inferring past particle paths, as used in prior protocols, our trace criterion provide stronger support for the claim of the counterfactuality of the communication. We… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.10165v1-abstract-full').style.display = 'inline'; document.getElementById('2308.10165v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2308.10165v1-abstract-full" style="display: none;"> We report an experimental realization of a modified counterfactual communication protocol that eliminates the dominant environmental trace left by photons passing through the transmission channel. Compared to Wheeler's criterion for inferring past particle paths, as used in prior protocols, our trace criterion provide stronger support for the claim of the counterfactuality of the communication. We verify the lack of trace left by transmitted photons via tagging the propagation arms of an interferometric device by distinct frequency-shifts and finding that the collected photons have no frequency shift which corresponds to the transmission channel. As a proof of principle, we counterfactually transfer a quick response code image with sufficient fidelity to be scanned with a cell phone. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.10165v1-abstract-full').style.display = 'none'; document.getElementById('2308.10165v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 20 August, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2023. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2308.03082">arXiv:2308.03082</a> <span> [<a href="https://arxiv.org/pdf/2308.03082">pdf</a>, <a href="https://arxiv.org/format/2308.03082">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Statistical Mechanics">cond-mat.stat-mech</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> </div> <p class="title is-5 mathjax"> Simulation of IBM's kicked Ising experiment with Projected Entangled Pair Operator </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Liao%2C+H">Hai-Jun Liao</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+K">Kang Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zong-Sheng Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+P">Pan Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Xiang%2C+T">Tao Xiang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2308.03082v1-abstract-short" style="display: inline;"> We perform classical simulations of the 127-qubit kicked Ising model, which was recently emulated using a quantum circuit with error mitigation [Nature 618, 500 (2023)]. Our approach is based on the projected entangled pair operator (PEPO) in the Heisenberg picture. Its main feature is the ability to automatically identify the underlying low-rank and low-entanglement structures in the quantum circ… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.03082v1-abstract-full').style.display = 'inline'; document.getElementById('2308.03082v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2308.03082v1-abstract-full" style="display: none;"> We perform classical simulations of the 127-qubit kicked Ising model, which was recently emulated using a quantum circuit with error mitigation [Nature 618, 500 (2023)]. Our approach is based on the projected entangled pair operator (PEPO) in the Heisenberg picture. Its main feature is the ability to automatically identify the underlying low-rank and low-entanglement structures in the quantum circuit involving Clifford and near-Clifford gates. We assess our approach using the quantum circuit with 5+1 trotter steps which was previously considered beyond classical verification. We develop a Clifford expansion theory to compute exact expectation values and use them to evaluate algorithms. The results indicate that PEPO significantly outperforms existing methods, including the tensor network with belief propagation, the matrix product operator, and the Clifford perturbation theory, in both efficiency and accuracy. In particular, PEPO with bond dimension $蠂=2$ already gives similar accuracy to the CPT with $K=10$ and MPO with bond dimension $蠂=1024$. And PEPO with $蠂=184$ provides exact results in $3$ seconds using a single CPU. Furthermore, we apply our method to the circuit with 20 Trotter steps. We observe the monotonic and consistent convergence of the results with $蠂$, allowing us to estimate the outcome with $蠂\to\infty$ through extrapolations. We then compare the extrapolated results to those achieved in quantum hardware and with existing tensor network methods. Additionally, we discuss the potential usefulness of our approach in simulating quantum circuits, especially in scenarios involving near-Clifford circuits and quantum approximate optimization algorithms. Our approach is the first use of PEPO in solving the time evolution problem, and our results suggest it could be a powerful tool for exploring the dynamical properties of quantum many-body systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.03082v1-abstract-full').style.display = 'none'; document.getElementById('2308.03082v1-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 August, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 pages, 3 figures</span> </p> </li> </ol> <nav class="pagination is-small is-centered breathe-horizontal" role="navigation" aria-label="pagination"> <a href="" class="pagination-previous 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