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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=Huang%2C+Y&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Huang%2C+Y&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=Huang%2C+Y&start=50" class="pagination-link " aria-label="Page 2" aria-current="page">2 </a> </li> <li> <a href="/search/?searchtype=author&query=Huang%2C+Y&start=100" class="pagination-link " aria-label="Page 3" aria-current="page">3 </a> </li> <li> <a href="/search/?searchtype=author&query=Huang%2C+Y&start=150" class="pagination-link " aria-label="Page 4" aria-current="page">4 </a> </li> <li> <a href="/search/?searchtype=author&query=Huang%2C+Y&start=200" class="pagination-link " aria-label="Page 5" aria-current="page">5 </a> </li> <li><span class="pagination-ellipsis">…</span></li> </ul> </nav> <ol class="breathe-horizontal" start="1"> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2412.01334">arXiv:2412.01334</a> <span> [<a href="https://arxiv.org/pdf/2412.01334">pdf</a>, <a href="https://arxiv.org/ps/2412.01334">ps</a>, <a href="https://arxiv.org/format/2412.01334">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"> Order-six CHMs containing exactly three distinct elements </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yanzu Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Liang%2C+M">Mengfan Liang</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+L">Lin 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="2412.01334v1-abstract-short" style="display: inline;"> Complex Hadamard matrices (CHMs) are intimately related to the number of distinct matrix elements. We investigate CHMs containing exactly three distinct elements, which is also the least number of distinct elements. In this paper, we show that such CHMs can only be complex equivalent to two kind of matrices, one is $H_2$-reducible and the other is the Tao matrix. Using our result one can further n… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.01334v1-abstract-full').style.display = 'inline'; document.getElementById('2412.01334v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.01334v1-abstract-full" style="display: none;"> Complex Hadamard matrices (CHMs) are intimately related to the number of distinct matrix elements. We investigate CHMs containing exactly three distinct elements, which is also the least number of distinct elements. In this paper, we show that such CHMs can only be complex equivalent to two kind of matrices, one is $H_2$-reducible and the other is the Tao matrix. Using our result one can further narrow the range of MUB trio (a set of four MUBs in $\mathbb{C}^6$ consists of an MUB trio and the identity) since we find that the two CHMs neither belong to MUB trios. Our results may lead to the more complete classification of $6\times 6$ CHMs whose elements in the first row are all 1. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.01334v1-abstract-full').style.display = 'none'; document.getElementById('2412.01334v1-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 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">29 pages, 0 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/2411.19561">arXiv:2411.19561</a> <span> [<a href="https://arxiv.org/pdf/2411.19561">pdf</a>, <a href="https://arxiv.org/format/2411.19561">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"> Observation of continuous time crystals and quasi-crystals in spin gases </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Ying Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+T">Tishuo Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Yin%2C+H">Haochuan Yin</a>, <a href="/search/quant-ph?searchtype=author&query=Jiang%2C+M">Min Jiang</a>, <a href="/search/quant-ph?searchtype=author&query=Luo%2C+Z">Zhihuang Luo</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+X">Xinhua Peng</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="2411.19561v1-abstract-short" style="display: inline;"> Continuous time crystal (CTC) and quasi-crystal (CTQC) are two novel phases of matter characterized by the spontaneous breaking of continuous time-translation symmetry. To date, realizations of CTCs with periodic oscillations have been reported in only a few physical platforms, and their complex properties still require further exploration. Additionally, CTQCs, which feature quasi-periodic oscilla… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.19561v1-abstract-full').style.display = 'inline'; document.getElementById('2411.19561v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.19561v1-abstract-full" style="display: none;"> Continuous time crystal (CTC) and quasi-crystal (CTQC) are two novel phases of matter characterized by the spontaneous breaking of continuous time-translation symmetry. To date, realizations of CTCs with periodic oscillations have been reported in only a few physical platforms, and their complex properties still require further exploration. Additionally, CTQCs, which feature quasi-periodic oscillations at multiple incommensurate frequencies, remain elusive. Here we report the experimental observation of CTC and CTQC signatures in noble-gas nuclear spins that interact nonlinearly with each other through feedback mechanisms. The observed limit cycle and quasi-periodic phases display persistent spin oscillations with coherence times extending beyond several hours. Notably, these oscillations are robust against noise perturbations and exhibit random time phases upon repetitive realization, epitomizing the continuous time-translation symmetry-breaking intrinsic to CTCs and CTQCs. As the feedback strength increases, the system undergoes a phase transition into a new phase characterized by chaotic oscillations, indicative of the ``melting" of time crystals. Interestingly, within certain feedback regimes, we even observe an unusual reverse phase transition from a chaotic phase back to time crystal phases. This work broadens the catalog of new phases of spin gas and unlocks opportunities in precision measurements, including multimode masers and tests of fundamental symmetries. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.19561v1-abstract-full').style.display = 'none'; document.getElementById('2411.19561v1-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, 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/2411.14607">arXiv:2411.14607</a> <span> [<a href="https://arxiv.org/pdf/2411.14607">pdf</a>, <a href="https://arxiv.org/format/2411.14607">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Instrumentation and Detectors">physics.ins-det</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Advanced LIGO detector performance in the fourth observing run </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Capote%2C+E">E. Capote</a>, <a href="/search/quant-ph?searchtype=author&query=Jia%2C+W">W. Jia</a>, <a href="/search/quant-ph?searchtype=author&query=Aritomi%2C+N">N. Aritomi</a>, <a href="/search/quant-ph?searchtype=author&query=Nakano%2C+M">M. Nakano</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+V">V. Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Abbott%2C+R">R. Abbott</a>, <a href="/search/quant-ph?searchtype=author&query=Abouelfettouh%2C+I">I. Abouelfettouh</a>, <a href="/search/quant-ph?searchtype=author&query=Adhikari%2C+R+X">R. X. Adhikari</a>, <a href="/search/quant-ph?searchtype=author&query=Ananyeva%2C+A">A. Ananyeva</a>, <a href="/search/quant-ph?searchtype=author&query=Appert%2C+S">S. Appert</a>, <a href="/search/quant-ph?searchtype=author&query=Apple%2C+S+K">S. K. Apple</a>, <a href="/search/quant-ph?searchtype=author&query=Arai%2C+K">K. Arai</a>, <a href="/search/quant-ph?searchtype=author&query=Aston%2C+S+M">S. M. Aston</a>, <a href="/search/quant-ph?searchtype=author&query=Ball%2C+M">M. Ball</a>, <a href="/search/quant-ph?searchtype=author&query=Ballmer%2C+S+W">S. W. Ballmer</a>, <a href="/search/quant-ph?searchtype=author&query=Barker%2C+D">D. Barker</a>, <a href="/search/quant-ph?searchtype=author&query=Barsotti%2C+L">L. Barsotti</a>, <a href="/search/quant-ph?searchtype=author&query=Berger%2C+B+K">B. K. Berger</a>, <a href="/search/quant-ph?searchtype=author&query=Betzwieser%2C+J">J. Betzwieser</a>, <a href="/search/quant-ph?searchtype=author&query=Bhattacharjee%2C+D">D. Bhattacharjee</a>, <a href="/search/quant-ph?searchtype=author&query=Billingsley%2C+G">G. Billingsley</a>, <a href="/search/quant-ph?searchtype=author&query=Biscans%2C+S">S. Biscans</a>, <a href="/search/quant-ph?searchtype=author&query=Blair%2C+C+D">C. D. Blair</a>, <a href="/search/quant-ph?searchtype=author&query=Bode%2C+N">N. Bode</a>, <a href="/search/quant-ph?searchtype=author&query=Bonilla%2C+E">E. Bonilla</a> , et al. (171 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2411.14607v1-abstract-short" style="display: inline;"> On May 24th, 2023, the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO), joined by the Advanced Virgo and KAGRA detectors, began the fourth observing run for a two-year-long dedicated search for gravitational waves. The LIGO Hanford and Livingston detectors have achieved an unprecedented sensitivity to gravitational waves, with an angle-averaged median range to binary neutron st… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.14607v1-abstract-full').style.display = 'inline'; document.getElementById('2411.14607v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.14607v1-abstract-full" style="display: none;"> On May 24th, 2023, the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO), joined by the Advanced Virgo and KAGRA detectors, began the fourth observing run for a two-year-long dedicated search for gravitational waves. The LIGO Hanford and Livingston detectors have achieved an unprecedented sensitivity to gravitational waves, with an angle-averaged median range to binary neutron star mergers of 152 Mpc and 160 Mpc, and duty cycles of 65.0% and 71.2%, respectively, with a coincident duty cycle of 52.6%. The maximum range achieved by the LIGO Hanford detector is 165 Mpc and the LIGO Livingston detector 177 Mpc, both achieved during the second part of the fourth observing run. For the fourth run, the quantum-limited sensitivity of the detectors was increased significantly due to the higher intracavity power from laser system upgrades and replacement of core optics, and from the addition of a 300 m filter cavity to provide the squeezed light with a frequency-dependent squeezing angle, part of the A+ upgrade program. Altogether, the A+ upgrades led to reduced detector-wide losses for the squeezed vacuum states of light which, alongside the filter cavity, enabled broadband quantum noise reduction of up to 5.2 dB at the Hanford observatory and 6.1 dB at the Livingston observatory. Improvements to sensors and actuators as well as significant controls commissioning increased low frequency sensitivity. This paper details these instrumental upgrades, analyzes the noise sources that limit detector sensitivity, and describes the commissioning challenges of the fourth observing run. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.14607v1-abstract-full').style.display = 'none'; document.getElementById('2411.14607v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">26 pages, 18 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> LIGO-P2400256 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.13882">arXiv:2411.13882</a> <span> [<a href="https://arxiv.org/pdf/2411.13882">pdf</a>, <a href="https://arxiv.org/format/2411.13882">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> A 2x2 quantum dot array in silicon with fully tuneable pairwise interdot coupling </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Lim%2C+W+H">Wee Han Lim</a>, <a href="/search/quant-ph?searchtype=author&query=Tanttu%2C+T">Tuomo Tanttu</a>, <a href="/search/quant-ph?searchtype=author&query=Youn%2C+T">Tony Youn</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+J+Y">Jonathan Yue Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Serrano%2C+S">Santiago Serrano</a>, <a href="/search/quant-ph?searchtype=author&query=Dickie%2C+A">Alexandra Dickie</a>, <a href="/search/quant-ph?searchtype=author&query=Yianni%2C+S">Steve Yianni</a>, <a href="/search/quant-ph?searchtype=author&query=Hudson%2C+F+E">Fay E. Hudson</a>, <a href="/search/quant-ph?searchtype=author&query=Escott%2C+C+C">Christopher C. Escott</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+C+H">Chih Hwan Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Laucht%2C+A">Arne Laucht</a>, <a href="/search/quant-ph?searchtype=author&query=Saraiva%2C+A">Andre Saraiva</a>, <a href="/search/quant-ph?searchtype=author&query=Chan%2C+K+W">Kok Wai Chan</a>, <a href="/search/quant-ph?searchtype=author&query=Cifuentes%2C+J+D">Jes煤s D. Cifuentes</a>, <a href="/search/quant-ph?searchtype=author&query=Dzurak%2C+A+S">Andrew S. Dzurak</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="2411.13882v1-abstract-short" style="display: inline;"> Recent advances in semiconductor spin qubits have achieved linear arrays exceeding ten qubits. Moving to two-dimensional (2D) qubit arrays is a critical next step to advance towards fault-tolerant implementations, but it poses substantial fabrication challenges, particularly because enabling control of nearest-neighbor entanglement requires the incorporation of interstitial exchange gates between… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.13882v1-abstract-full').style.display = 'inline'; document.getElementById('2411.13882v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.13882v1-abstract-full" style="display: none;"> Recent advances in semiconductor spin qubits have achieved linear arrays exceeding ten qubits. Moving to two-dimensional (2D) qubit arrays is a critical next step to advance towards fault-tolerant implementations, but it poses substantial fabrication challenges, particularly because enabling control of nearest-neighbor entanglement requires the incorporation of interstitial exchange gates between quantum dots in the qubit architecture. In this work, we present a 2D array of silicon metal-oxide-semiconductor (MOS) quantum dots with tunable interdot coupling between all adjacent dots. The device is characterized at 4.2 K, where we demonstrate the formation and isolation of double-dot and triple-dot configurations. We show control of all nearest-neighbor tunnel couplings spanning up to 30 decades per volt through the interstitial exchange gates and use advanced modeling tools to estimate the exchange interactions that could be realized among qubits in this architecture. These results represent a significant step towards the development of 2D MOS quantum processors compatible with foundry manufacturing techniques. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.13882v1-abstract-full').style.display = 'none'; document.getElementById('2411.13882v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">9 pages, 5 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.13437">arXiv:2411.13437</a> <span> [<a href="https://arxiv.org/pdf/2411.13437">pdf</a>, <a href="https://arxiv.org/format/2411.13437">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"> Improved fluxonium readout through dynamic flux pulsing </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Stefanski%2C+T+V">Taryn V. Stefanski</a>, <a href="/search/quant-ph?searchtype=author&query=Yilmaz%2C+F">Figen Yilmaz</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+E+Y">Eugene Y. Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Zwanenburg%2C+M+F+S">Martijn F. S. Zwanenburg</a>, <a href="/search/quant-ph?searchtype=author&query=Singh%2C+S">Siddharth Singh</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+S">Siyu Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Splitthoff%2C+L+J">Lukas J. Splitthoff</a>, <a href="/search/quant-ph?searchtype=author&query=Andersen%2C+C+K">Christian Kraglund Andersen</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="2411.13437v1-abstract-short" style="display: inline;"> The ability to perform rapid, high fidelity readout of a qubit state is an important requirement for quantum algorithms and, in particular, for enabling operations such as mid-circuit measurements and measurement-based feedback for error correction schemes on large quantum processors. The growing interest in fluxonium qubits, due to their long coherence times and high anharmonicity, merits further… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.13437v1-abstract-full').style.display = 'inline'; document.getElementById('2411.13437v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.13437v1-abstract-full" style="display: none;"> The ability to perform rapid, high fidelity readout of a qubit state is an important requirement for quantum algorithms and, in particular, for enabling operations such as mid-circuit measurements and measurement-based feedback for error correction schemes on large quantum processors. The growing interest in fluxonium qubits, due to their long coherence times and high anharmonicity, merits further attention to reducing the readout duration and measurement errors. We find that this can be accomplished by exploiting the flux tunability of fluxonium qubits. In this work, we experimentally demonstrate flux-pulse-assisted readout, as proposed in Phys. Rev. Applied 22, 014079 (https://doi.org/10.1103/PhysRevApplied.22.014079), in a setup without a quantum-limited parametric amplifier. Increasing the dispersive shift magnitude by almost 20% through flux pulsing, we achieve an assignment fidelity of 94.3% with an integration time of 280 ns. The readout performance is limited by state initialization, but we find that the limit imposed only by the signal-to-noise ratio corresponds to an assignment fidelity of 99.9% with a 360 ns integration time. We also verify these results through simple semi-classical simulations. These results constitute the fastest reported readout of a fluxonium qubit, with the prospect of further improvement by incorporation of a parametric amplifier in the readout chain to enhance measurement efficiency. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.13437v1-abstract-full').style.display = 'none'; document.getElementById('2411.13437v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 20 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2024. </p> <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, 1 table</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.06828">arXiv:2411.06828</a> <span> [<a href="https://arxiv.org/pdf/2411.06828">pdf</a>, <a href="https://arxiv.org/format/2411.06828">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"> Test-Time Training with Quantum Auto-Encoder: From Distribution Shift to Noisy Quantum Circuits </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Jian%2C+D">Damien Jian</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yu-Chao Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Goan%2C+H">Hsi-Sheng Goan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2411.06828v1-abstract-short" style="display: inline;"> In this paper, we propose test-time training with the quantum auto-encoder (QTTT). QTTT adapts to (1) data distribution shifts between training and testing data and (2) quantum circuit error by minimizing the self-supervised loss of the quantum auto-encoder. Empirically, we show that QTTT is robust against data distribution shifts and effective in mitigating random unitary noise in the quantum cir… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.06828v1-abstract-full').style.display = 'inline'; document.getElementById('2411.06828v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.06828v1-abstract-full" style="display: none;"> In this paper, we propose test-time training with the quantum auto-encoder (QTTT). QTTT adapts to (1) data distribution shifts between training and testing data and (2) quantum circuit error by minimizing the self-supervised loss of the quantum auto-encoder. Empirically, we show that QTTT is robust against data distribution shifts and effective in mitigating random unitary noise in the quantum circuits during the inference. Additionally, we establish the theoretical performance guarantee of the QTTT architecture. Our novel framework presents a significant advancement in developing quantum neural networks for future real-world applications and functions as a plug-and-play extension for quantum machine learning models. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.06828v1-abstract-full').style.display = 'none'; document.getElementById('2411.06828v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">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">14 pages</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.00391">arXiv:2411.00391</a> <span> [<a href="https://arxiv.org/pdf/2411.00391">pdf</a>, <a href="https://arxiv.org/format/2411.00391">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"> Enhanced Analysis for the Decoy-State Method </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Xu%2C+Z">Zitai Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yizhi Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Ma%2C+X">Xiongfeng 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="2411.00391v1-abstract-short" style="display: inline;"> Quantum key distribution is a cornerstone of quantum cryptography, enabling secure communication through the principles of quantum mechanics. In reality, most practical implementations rely on the decoy-state method to ensure security against photon-number-splitting attacks. A significant challenge in realistic quantum cryptosystems arises from statistical fluctuations with finite data sizes, whic… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.00391v1-abstract-full').style.display = 'inline'; document.getElementById('2411.00391v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.00391v1-abstract-full" style="display: none;"> Quantum key distribution is a cornerstone of quantum cryptography, enabling secure communication through the principles of quantum mechanics. In reality, most practical implementations rely on the decoy-state method to ensure security against photon-number-splitting attacks. A significant challenge in realistic quantum cryptosystems arises from statistical fluctuations with finite data sizes, which complicate the key-rate estimation due to the nonlinear dependence on the phase error rate. In this study, we first revisit and improve the key rate bound for the decoy-state method. We then propose an enhanced framework for statistical fluctuation analysis. By employing our fluctuation analysis on the improved bound, we demonstrate enhancement in key generation rates through numerical simulations with typical experimental parameters. Furthermore, our approach to fluctuation analysis is not only applicable in quantum cryptography but can also be adapted to other quantum information processing tasks, particularly when the objective and experimental variables exhibit a linear relationship. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.00391v1-abstract-full').style.display = 'none'; document.getElementById('2411.00391v1-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, 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">20 pages, 7 figures, and 2 tables</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.00316">arXiv:2411.00316</a> <span> [<a href="https://arxiv.org/pdf/2411.00316">pdf</a>, <a href="https://arxiv.org/format/2411.00316">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Networking and Internet Architecture">cs.NI</span> </div> </div> <p class="title is-5 mathjax"> Quantum Entanglement Path Selection and Qubit Allocation via Adversarial Group Neural Bandits </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yin Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+L">Lei Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+J">Jie Xu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2411.00316v1-abstract-short" style="display: inline;"> Quantum Data Networks (QDNs) have emerged as a promising framework in the field of information processing and transmission, harnessing the principles of quantum mechanics. QDNs utilize a quantum teleportation technique through long-distance entanglement connections, encoding data information in quantum bits (qubits). Despite being a cornerstone in various quantum applications, quantum entanglement… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.00316v1-abstract-full').style.display = 'inline'; document.getElementById('2411.00316v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.00316v1-abstract-full" style="display: none;"> Quantum Data Networks (QDNs) have emerged as a promising framework in the field of information processing and transmission, harnessing the principles of quantum mechanics. QDNs utilize a quantum teleportation technique through long-distance entanglement connections, encoding data information in quantum bits (qubits). Despite being a cornerstone in various quantum applications, quantum entanglement encounters challenges in establishing connections over extended distances due to probabilistic processes influenced by factors like optical fiber losses. The creation of long-distance entanglement connections between quantum computers involves multiple entanglement links and entanglement swapping techniques through successive quantum nodes, including quantum computers and quantum repeaters, necessitating optimal path selection and qubit allocation. Current research predominantly assumes known success rates of entanglement links between neighboring quantum nodes and overlooks potential network attackers. This paper addresses the online challenge of optimal path selection and qubit allocation, aiming to learn the best strategy for achieving the highest success rate of entanglement connections between two chosen quantum computers without prior knowledge of the success rate and in the presence of a QDN attacker. The proposed approach is based on multi-armed bandits, specifically adversarial group neural bandits, which treat each path as a group and view qubit allocation as arm selection. Our contributions encompass formulating an online adversarial optimization problem, introducing the EXPNeuralUCB bandits algorithm with theoretical performance guarantees, and conducting comprehensive simulations to showcase its superiority over established advanced algorithms. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.00316v1-abstract-full').style.display = 'none'; document.getElementById('2411.00316v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 31 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> 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">Accepted by IEEE/ACM Transactions on Networking</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.17471">arXiv:2410.17471</a> <span> [<a href="https://arxiv.org/pdf/2410.17471">pdf</a>, <a href="https://arxiv.org/format/2410.17471">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> </div> </div> <p class="title is-5 mathjax"> First Photon Machine Learning </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+L">Lili Li</a>, <a href="/search/quant-ph?searchtype=author&query=Kumar%2C+S">Santosh Kumar</a>, <a href="/search/quant-ph?searchtype=author&query=Garikapati%2C+M">Malvika Garikapati</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yu-Ping Huang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2410.17471v1-abstract-short" style="display: inline;"> Quantum techniques are expected to revolutionize how information is acquired, exchanged, and processed. Yet it has been a challenge to realize and measure their values in practical settings. We present first photon machine learning as a new paradigm of neural networks and establish the first unambiguous advantage of quantum effects for artificial intelligence. By extending the physics behind the d… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.17471v1-abstract-full').style.display = 'inline'; document.getElementById('2410.17471v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.17471v1-abstract-full" style="display: none;"> Quantum techniques are expected to revolutionize how information is acquired, exchanged, and processed. Yet it has been a challenge to realize and measure their values in practical settings. We present first photon machine learning as a new paradigm of neural networks and establish the first unambiguous advantage of quantum effects for artificial intelligence. By extending the physics behind the double-slit experiment for quantum particles to a many-slit version, our experiment finds that a single photon can perform image recognition at around $30\%$ fidelity, which beats by a large margin the theoretical limit of what a similar classical system can possibly achieve (about 24\%). In this experiment, the entire neural network is implemented in sub-attojoule optics and the equivalent per-calculation energy cost is below $10^{-24}$ joule, highlighting the prospects of quantum optical machine learning for unparalleled advantages in speed, capacity, and energy efficiency. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.17471v1-abstract-full').style.display = 'none'; document.getElementById('2410.17471v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">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">19 pages, 5 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2409.11833">arXiv:2409.11833</a> <span> [<a href="https://arxiv.org/pdf/2409.11833">pdf</a>, <a href="https://arxiv.org/format/2409.11833">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="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Spin resolved momentum spectra for vacuum pair production via a generalized two level model </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Amat%2C+O">Orkash Amat</a>, <a href="/search/quant-ph?searchtype=author&query=Fan%2C+H">Hong-Hao Fan</a>, <a href="/search/quant-ph?searchtype=author&query=Tang%2C+S">Suo Tang</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yong-Feng Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Xie%2C+B">Bai-Song Xie</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="2409.11833v1-abstract-short" style="display: inline;"> We have formulated a generalized two level model for studying the pair production in multidimensional time-dependent electric fields. It can provide momentum spectra with fully spin resolved components for all possible combined spin states of the particle and anti-particle simultaneously. Moreover, we have also investigated the validity of the two level model for fermions (scalar particles) by com… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.11833v1-abstract-full').style.display = 'inline'; document.getElementById('2409.11833v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.11833v1-abstract-full" style="display: none;"> We have formulated a generalized two level model for studying the pair production in multidimensional time-dependent electric fields. It can provide momentum spectra with fully spin resolved components for all possible combined spin states of the particle and anti-particle simultaneously. Moreover, we have also investigated the validity of the two level model for fermions (scalar particles) by comparing the results with those by equal-time Dirac-Heisenberg-Wigner (Feshbach-Villars-Heisenberg-Wigner) formalism in different regimes of pair creation, i.e., multiphoton and tunneling dominated mechanisms. It is found that the results are consistent with each other, indicating the good approximation of the two level model. In particular, in terms of the two level model, we found that the contribution of the particle momentum spectra is the greatest when the spin states of the particle and anti-particle are parallel with $S=1$. It is believed that by this two level model one can extend researches on pair production for more different background fields, such as a slowly varying spatial-temporal one. Many other interesting phenomena may also be revealed, including the spin-resolved vortex structure that is contained in the phase feature of the distribution function of the created pairs. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.11833v1-abstract-full').style.display = 'none'; document.getElementById('2409.11833v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">35 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/2409.08436">arXiv:2409.08436</a> <span> [<a href="https://arxiv.org/pdf/2409.08436">pdf</a>, <a href="https://arxiv.org/ps/2409.08436">ps</a>, <a href="https://arxiv.org/format/2409.08436">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Statistical Mechanics">cond-mat.stat-mech</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mathematical Physics">math-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Random product states at high temperature equilibrate exponentially well </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yichen Huang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2409.08436v1-abstract-short" style="display: inline;"> We prove that for all but a measure zero set of local Hamiltonians, starting from random product states at sufficiently high but finite temperature, with overwhelming probability expectation values of observables equilibrate such that at sufficiently long times, fluctuations around the stationary value are exponentially small in the system size. </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.08436v1-abstract-full" style="display: none;"> We prove that for all but a measure zero set of local Hamiltonians, starting from random product states at sufficiently high but finite temperature, with overwhelming probability expectation values of observables equilibrate such that at sufficiently long times, fluctuations around the stationary value are exponentially small in the system size. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.08436v1-abstract-full').style.display = 'none'; document.getElementById('2409.08436v1-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 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2409.07731">arXiv:2409.07731</a> <span> [<a href="https://arxiv.org/pdf/2409.07731">pdf</a>, <a href="https://arxiv.org/format/2409.07731">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Group delay controlled by the decoherence of a single artificial atom </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Cheng%2C+Y+-">Y. -T. Cheng</a>, <a href="/search/quant-ph?searchtype=author&query=Hsieh%2C+K+-">K. -M. Hsieh</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+B+-">B. -Y. Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Niu%2C+Z+Q">Z. Q. Niu</a>, <a href="/search/quant-ph?searchtype=author&query=Aziz%2C+F">F. Aziz</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y+-">Y. -H. Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Wen%2C+P+Y">P. Y. Wen</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+K+-">K. -T. Lin</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+Y+-">Y. -H. Lin</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+J+C">J. C. Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Kockum%2C+A+F">A. F. Kockum</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+G+-">G. -D. Lin</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+Z+-">Z. -R. Lin</a>, <a href="/search/quant-ph?searchtype=author&query=Lu%2C+Y">Y. Lu</a>, <a href="/search/quant-ph?searchtype=author&query=Hoi%2C+I+-">I. -C. Hoi</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2409.07731v1-abstract-short" style="display: inline;"> The ability to slow down light at the single-photon level has applications in quantum information processing and other quantum technologies. We demonstrate two methods, both using just a single artificial atom, enabling dynamic control over microwave light velocities in waveguide quantum electrodynamics (waveguide QED). Our methods are based on two distinct mechanisms harnessing the balance betwee… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.07731v1-abstract-full').style.display = 'inline'; document.getElementById('2409.07731v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.07731v1-abstract-full" style="display: none;"> The ability to slow down light at the single-photon level has applications in quantum information processing and other quantum technologies. We demonstrate two methods, both using just a single artificial atom, enabling dynamic control over microwave light velocities in waveguide quantum electrodynamics (waveguide QED). Our methods are based on two distinct mechanisms harnessing the balance between radiative and non-radiative decay rates of a superconducting artificial atom in front of a mirror. In the first method, we tune the radiative decay of the atom using interference effects due to the mirror; in the second method, we pump the atom to control its non-radiative decay through the Autler--Townes effect. When the half the radiative decay rate exceeds the non-radiative decay rate, we observe positive group delay; conversely, dominance of the non-radiative decay rate results in negative group delay. Our results advance signal-processing capabilities in waveguide QED. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.07731v1-abstract-full').style.display = 'none'; document.getElementById('2409.07731v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2409.07043">arXiv:2409.07043</a> <span> [<a href="https://arxiv.org/pdf/2409.07043">pdf</a>, <a href="https://arxiv.org/ps/2409.07043">ps</a>, <a href="https://arxiv.org/format/2409.07043">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Theory">hep-th</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Disordered Systems and Neural Networks">cond-mat.dis-nn</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Statistical Mechanics">cond-mat.stat-mech</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mathematical Physics">math-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Deviations from maximal entanglement for eigenstates of the Sachdev-Ye-Kitaev model </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yichen Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Tan%2C+Y">Yi Tan</a>, <a href="/search/quant-ph?searchtype=author&query=Yao%2C+N+Y">Norman Y. Yao</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="2409.07043v1-abstract-short" style="display: inline;"> We consider mid-spectrum eigenstates of the Sachdev-Ye-Kiteav (SYK) model. We prove that for subsystems whose size is a constant fraction of the system size, the entanglement entropy deviates from the maximum entropy by at least a positive constant. This result highlights the difference between the entanglement entropy of mid-spectrum eigenstates of the SYK model and that of random states. </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.07043v1-abstract-full" style="display: none;"> We consider mid-spectrum eigenstates of the Sachdev-Ye-Kiteav (SYK) model. We prove that for subsystems whose size is a constant fraction of the system size, the entanglement entropy deviates from the maximum entropy by at least a positive constant. This result highlights the difference between the entanglement entropy of mid-spectrum eigenstates of the SYK model and that of random states. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.07043v1-abstract-full').style.display = 'none'; document.getElementById('2409.07043v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2409.04752">arXiv:2409.04752</a> <span> [<a href="https://arxiv.org/pdf/2409.04752">pdf</a>, <a href="https://arxiv.org/format/2409.04752">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"> Qubit Mapping: The Adaptive Divide-and-Conquer Approach </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yunqi Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+X">Xiangzhen Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Meng%2C+F">Fanxu Meng</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Sanjiang Li</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2409.04752v1-abstract-short" style="display: inline;"> The qubit mapping problem (QMP) focuses on the mapping and routing of qubits in quantum circuits so that the strict connectivity constraints imposed by near-term quantum hardware are satisfied. QMP is a pivotal task for quantum circuit compilation and its decision version is NP-complete. In this study, we present an effective approach called Adaptive Divided-And-Conqure (ADAC) to solve QMP. Our AD… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.04752v1-abstract-full').style.display = 'inline'; document.getElementById('2409.04752v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.04752v1-abstract-full" style="display: none;"> The qubit mapping problem (QMP) focuses on the mapping and routing of qubits in quantum circuits so that the strict connectivity constraints imposed by near-term quantum hardware are satisfied. QMP is a pivotal task for quantum circuit compilation and its decision version is NP-complete. In this study, we present an effective approach called Adaptive Divided-And-Conqure (ADAC) to solve QMP. Our ADAC algorithm adaptively partitions circuits by leveraging subgraph isomorphism and ensuring coherence among subcircuits. Additionally, we employ a heuristic approach to optimise the routing algorithm during circuit partitioning. Through extensive experiments across various NISQ devices and circuit benchmarks, we demonstrate that the proposed ADAC algorithm outperforms the state-of-the-art method. Specifically, ADAC shows an improvement of nearly 50\% on the IBM Tokyo architecture. Furthermore, ADAC exhibits an improvement of around 18\% on pseudo-realistic circuits implemented on grid-like architectures with larger qubit numbers, where the pseudo-realistic circuits are constructed based on the characteristics of widely existing realistic circuits, aiming to investigate the applicability of ADAC. Our findings highlight the potential of ADAC in quantum circuit compilation and the deployment of practical applications on near-term quantum hardware platforms. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.04752v1-abstract-full').style.display = 'none'; document.getElementById('2409.04752v1-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 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/2409.03217">arXiv:2409.03217</a> <span> [<a href="https://arxiv.org/pdf/2409.03217">pdf</a>, <a href="https://arxiv.org/format/2409.03217">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 Catalytic Amplification of Asymmetry </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+C">Chao Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Hu%2C+X">Xiao-Min Hu</a>, <a href="/search/quant-ph?searchtype=author&query=Ding%2C+F">Feng Ding</a>, <a href="/search/quant-ph?searchtype=author&query=Hu%2C+X">Xue-Yuan Hu</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Y">Yu Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+B">Bi-Heng Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yun-Feng Huang</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="2409.03217v2-abstract-short" style="display: inline;"> The manipulation and transformation of quantum resources are key parts of quantum mechanics. Among them, asymmetry is one of the most useful operational resources, which is widely used in quantum clocks, quantum metrology, and other tasks. Recent studies have shown that the asymmetry of quantum states can be significantly amplified with the assistance of correlating catalysts which are finite-dime… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.03217v2-abstract-full').style.display = 'inline'; document.getElementById('2409.03217v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.03217v2-abstract-full" style="display: none;"> The manipulation and transformation of quantum resources are key parts of quantum mechanics. Among them, asymmetry is one of the most useful operational resources, which is widely used in quantum clocks, quantum metrology, and other tasks. Recent studies have shown that the asymmetry of quantum states can be significantly amplified with the assistance of correlating catalysts which are finite-dimensional auxiliaries. In the experiment, we perform translationally invariant operations, ensuring that the asymmetric resources of the entire system remain non-increasing, on a composite system composed of a catalytic system and a quantum system. The experimental results demonstrate an asymmetry amplification of 0.0172\pm0.0022 in the system following the catalytic process. Our work showcases the potential of quantum catalytic processes and is expected to inspire further research in the field of quantum resource theories. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.03217v2-abstract-full').style.display = 'none'; document.getElementById('2409.03217v2-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 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 4 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">17pages,7figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2409.03185">arXiv:2409.03185</a> <span> [<a href="https://arxiv.org/pdf/2409.03185">pdf</a>, <a href="https://arxiv.org/format/2409.03185">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Emerging Technologies">cs.ET</span> </div> </div> <p class="title is-5 mathjax"> DasAtom: A Divide-and-Shuttle Atom Approach to Quantum Circuit Transformation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yunqi Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Gao%2C+D">Dingchao Gao</a>, <a href="/search/quant-ph?searchtype=author&query=Ying%2C+S">Shenggang Ying</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Sanjiang Li</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2409.03185v1-abstract-short" style="display: inline;"> Neutral atom (NA) quantum systems are emerging as a leading platform for quantum computation, offering superior or competitive qubit count and gate fidelity compared to superconducting circuits and ion traps. However, the unique features of NA devices, such as long-range interactions, long qubit coherence time, and the ability to physically move qubits, present distinct challenges for quantum circ… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.03185v1-abstract-full').style.display = 'inline'; document.getElementById('2409.03185v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.03185v1-abstract-full" style="display: none;"> Neutral atom (NA) quantum systems are emerging as a leading platform for quantum computation, offering superior or competitive qubit count and gate fidelity compared to superconducting circuits and ion traps. However, the unique features of NA devices, such as long-range interactions, long qubit coherence time, and the ability to physically move qubits, present distinct challenges for quantum circuit compilation. In this paper, we introduce DasAtom, a novel divide-and-shuttle atom approach designed to optimise quantum circuit transformation for NA devices by leveraging these capabilities. DasAtom partitions circuits into subcircuits, each associated with a qubit mapping that allows all gates within the subcircuit to be directly executed. The algorithm then shuttles atoms to transition seamlessly from one mapping to the next, enhancing both execution efficiency and overall fidelity. For a 30-qubit Quantum Fourier Transform (QFT), DasAtom achieves a 414x improvement in fidelity over the move-based algorithm Enola and a 10.6x improvement over the SWAP-based algorithm Tetris. Notably, this improvement is expected to increase exponentially with the number of qubits, positioning DasAtom as a highly promising solution for scaling quantum computation on NA platforms. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.03185v1-abstract-full').style.display = 'none'; document.getElementById('2409.03185v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2409.03145">arXiv:2409.03145</a> <span> [<a href="https://arxiv.org/pdf/2409.03145">pdf</a>, <a href="https://arxiv.org/format/2409.03145">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Exceptional topology in Non-Hermitian Twisted Bilayer Graphene </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yingyi Huang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2409.03145v2-abstract-short" style="display: inline;"> Twisted bilayer graphene has extraordinary electronic properties at the magic angle along with an isolated flat band at magic angle. However, the non-Hermitian phenomena in twisted bilayer graphene remain unexplored. In this work, we study a non-Hermitian TBG formed by one-layer graphene twisted relative to another layer with gain and loss. Using a non-Hermitian generalization of Bistritzer-MacDon… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.03145v2-abstract-full').style.display = 'inline'; document.getElementById('2409.03145v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.03145v2-abstract-full" style="display: none;"> Twisted bilayer graphene has extraordinary electronic properties at the magic angle along with an isolated flat band at magic angle. However, the non-Hermitian phenomena in twisted bilayer graphene remain unexplored. In this work, we study a non-Hermitian TBG formed by one-layer graphene twisted relative to another layer with gain and loss. Using a non-Hermitian generalization of Bistritzer-MacDonald model, we find Dirac cones centered at only $K_M$ ($K'_M$) corner of the moir茅 Brillouin zone at $K'$ ($K$) valley deformed in the presence of non-Hermiticity. This is different from single layer graphene with gain and loss, where rings of exceptional points appear in both $K$ and $K'$ corners of the Brillouin zone.The coincident of exceptional rings at $螕_M$ point characterizes an ``exceptional magic angle", at which the system hosts flat bands with zero energy and finite lifetime. More interestingly, we find that the topological charge in the moir茅 Brillouin zone is conserved during the expansion and fusion of the exceptional ring, which is absent in two-dimensional systems constraining by Nielsen-Ninomiya theorem.These findings can be demonstrated in realistic cold atom and metamaterial systems and will stimulate further study on non-Hermitian phenomena in twistronic. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.03145v2-abstract-full').style.display = 'none'; document.getElementById('2409.03145v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 4 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">5 pages, 4 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.15225">arXiv:2408.15225</a> <span> [<a href="https://arxiv.org/pdf/2408.15225">pdf</a>, <a href="https://arxiv.org/format/2408.15225">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Numerical Analysis">math.NA</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"> Automated Synthesis of Quantum Algorithms via Classical Numerical Techniques </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yuxin Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Grossman-Ponemon%2C+B+E">Benjamin E. Grossman-Ponemon</a>, <a href="/search/quant-ph?searchtype=author&query=Hyde%2C+D+A+B">David A. B. Hyde</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="2408.15225v1-abstract-short" style="display: inline;"> We apply numerical optimization and linear algebra algorithms for classical computers to the problem of automatically synthesizing algorithms for quantum computers. Using our framework, we apply several common techniques from these classical domains and numerically examine their suitability for and performance on this problem. Our methods are evaluated on single-qubit systems as well as on larger… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.15225v1-abstract-full').style.display = 'inline'; document.getElementById('2408.15225v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.15225v1-abstract-full" style="display: none;"> We apply numerical optimization and linear algebra algorithms for classical computers to the problem of automatically synthesizing algorithms for quantum computers. Using our framework, we apply several common techniques from these classical domains and numerically examine their suitability for and performance on this problem. Our methods are evaluated on single-qubit systems as well as on larger systems. While the first part of our proposed method outputs a single unitary matrix representing the composite effects of a quantum circuit or algorithm, we use existing tools - and assess the performance of these - to factor such a matrix into a product of elementary quantum gates. This enables our pipeline to be truly end-to-end: starting from desired input/output examples, our code ultimately results in a quantum circuit diagram. We release our code to the research community (upon acceptance). <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.15225v1-abstract-full').style.display = 'none'; document.getElementById('2408.15225v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">17 pages, 9 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">MSC Class:</span> 65-04; 81P68 <span class="has-text-black-bis has-text-weight-semibold">ACM Class:</span> G.1.10; G.1.3; G.1.6; G.4 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.14373">arXiv:2408.14373</a> <span> [<a href="https://arxiv.org/pdf/2408.14373">pdf</a>, <a href="https://arxiv.org/format/2408.14373">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 Single-Ion Information Engine for Charging Quantum Battery </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+J">Jialiang Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+P">Pengfei Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+W">Wentao Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Cai%2C+Z">Zhengyang Cai</a>, <a href="/search/quant-ph?searchtype=author&query=Qiao%2C+M">Mu Qiao</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+R">Riling Li</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yingye Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Tian%2C+H">Haonan Tian</a>, <a href="/search/quant-ph?searchtype=author&query=Tu%2C+H">Henchao Tu</a>, <a href="/search/quant-ph?searchtype=author&query=Cui%2C+K">Kaifeng Cui</a>, <a href="/search/quant-ph?searchtype=author&query=Yan%2C+L">Leilei Yan</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+J">Junhua Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+J">Jingning Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Yung%2C+M">Manhong Yung</a>, <a href="/search/quant-ph?searchtype=author&query=Kim%2C+K">Kihwan Kim</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2408.14373v1-abstract-short" style="display: inline;"> Information engines produce mechanical work through measurement and adaptive control. For information engines, the principal challenge lies in how to store the generated work for subsequent utilization. Here, we report an experimental demonstration where quantized mechanical motion serves as a quantum battery and gets charged in repeated cycles by a single trapped-ion information engine. This is e… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.14373v1-abstract-full').style.display = 'inline'; document.getElementById('2408.14373v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.14373v1-abstract-full" style="display: none;"> Information engines produce mechanical work through measurement and adaptive control. For information engines, the principal challenge lies in how to store the generated work for subsequent utilization. Here, we report an experimental demonstration where quantized mechanical motion serves as a quantum battery and gets charged in repeated cycles by a single trapped-ion information engine. This is enabled by a key technological advancement in rapid state discrimination, allowing us to suppress measurement-induced disturbances. Consequently, we were able to obtain a charging efficiency over 50\% of the theoretical limit at the optimal temperature. The experimental results substantiate that this approach can render trapped ions a promising platform for microscopic information engines with potential applications in the future upon scaling up. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.14373v1-abstract-full').style.display = 'none'; document.getElementById('2408.14373v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 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/2407.16558">arXiv:2407.16558</a> <span> [<a href="https://arxiv.org/pdf/2407.16558">pdf</a>, <a href="https://arxiv.org/format/2407.16558">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> </div> </div> <p class="title is-5 mathjax"> Parrondo's paradox in quantum walks with inhomogeneous coins </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Mittal%2C+V">Vikash Mittal</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yi-Ping Huang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2407.16558v1-abstract-short" style="display: inline;"> Parrondo's paradox, a counterintuitive phenomenon where two losing strategies combine to produce a winning outcome, has been a subject of interest across various scientific fields, including quantum mechanics. In this study, we investigate the manifestation of Parrondo's paradox in discrete-time quantum walks. We demonstrate the existence of Parrondo's paradox using space and time-dependent coins… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.16558v1-abstract-full').style.display = 'inline'; document.getElementById('2407.16558v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.16558v1-abstract-full" style="display: none;"> Parrondo's paradox, a counterintuitive phenomenon where two losing strategies combine to produce a winning outcome, has been a subject of interest across various scientific fields, including quantum mechanics. In this study, we investigate the manifestation of Parrondo's paradox in discrete-time quantum walks. We demonstrate the existence of Parrondo's paradox using space and time-dependent coins without the need for a higher-dimensional coin or adding decoherence to the system. Our results enhance the feasibility of practical implementations and provide deeper insights into the underlying quantum dynamics, specifically the propagation constrained by the interference pattern of quantum walks. The implications of our results suggest the potential for more accessible and efficient designs in quantum transport, broadening the scope and application of Parrondo's paradox beyond conventional frameworks. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.16558v1-abstract-full').style.display = 'none'; document.getElementById('2407.16558v1-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 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">Comments and suggestions are most welcome</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.15778">arXiv:2407.15778</a> <span> [<a href="https://arxiv.org/pdf/2407.15778">pdf</a>, <a href="https://arxiv.org/format/2407.15778">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Violating Bell's inequality in gate-defined quantum dots </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Steinacker%2C+P">Paul Steinacker</a>, <a href="/search/quant-ph?searchtype=author&query=Tanttu%2C+T">Tuomo Tanttu</a>, <a href="/search/quant-ph?searchtype=author&query=Lim%2C+W+H">Wee Han Lim</a>, <a href="/search/quant-ph?searchtype=author&query=Stuyck%2C+N+D">Nard Dumoulin Stuyck</a>, <a href="/search/quant-ph?searchtype=author&query=Feng%2C+M">MengKe Feng</a>, <a href="/search/quant-ph?searchtype=author&query=Serrano%2C+S">Santiago Serrano</a>, <a href="/search/quant-ph?searchtype=author&query=Vahapoglu%2C+E">Ensar Vahapoglu</a>, <a href="/search/quant-ph?searchtype=author&query=Su%2C+R+Y">Rocky Y. Su</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+J+Y">Jonathan Y. Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Jones%2C+C">Cameron Jones</a>, <a href="/search/quant-ph?searchtype=author&query=Itoh%2C+K+M">Kohei M. Itoh</a>, <a href="/search/quant-ph?searchtype=author&query=Hudson%2C+F+E">Fay E. Hudson</a>, <a href="/search/quant-ph?searchtype=author&query=Escott%2C+C+C">Christopher C. Escott</a>, <a href="/search/quant-ph?searchtype=author&query=Morello%2C+A">Andrea Morello</a>, <a href="/search/quant-ph?searchtype=author&query=Saraiva%2C+A">Andre Saraiva</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+C+H">Chih Hwan Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Dzurak%2C+A+S">Andrew S. Dzurak</a>, <a href="/search/quant-ph?searchtype=author&query=Laucht%2C+A">Arne Laucht</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="2407.15778v2-abstract-short" style="display: inline;"> Superior computational power promised by quantum computers utilises the fundamental quantum mechanical principle of entanglement. However, achieving entanglement and verifying that the generated state does not follow the principle of local causality has proven difficult for spin qubits in gate-defined quantum dots, as it requires simultaneously high concurrence values and readout fidelities to bre… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.15778v2-abstract-full').style.display = 'inline'; document.getElementById('2407.15778v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.15778v2-abstract-full" style="display: none;"> Superior computational power promised by quantum computers utilises the fundamental quantum mechanical principle of entanglement. However, achieving entanglement and verifying that the generated state does not follow the principle of local causality has proven difficult for spin qubits in gate-defined quantum dots, as it requires simultaneously high concurrence values and readout fidelities to break the classical bound imposed by Bell's inequality. Here we employ heralded initialization and calibration via gate set tomography (GST), to reduce all relevant errors and push the fidelities of the full 2-qubit gate set above 99 %, including state preparation and measurement (SPAM). We demonstrate a 97.17 % Bell state fidelity without correcting for readout errors and violate Bell's inequality with a Bell signal of S = 2.731 close to the theoretical maximum of $2\sqrt{2}$. Our measurements exceed the classical limit even at elevated temperatures of 1.1 K or entanglement lifetimes of 100 $渭s$. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.15778v2-abstract-full').style.display = 'none'; document.getElementById('2407.15778v2-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 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 22 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">19 pages, 5 main figures, 9 extended data figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">MSC Class:</span> 81P68; 81-05 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.14761">arXiv:2407.14761</a> <span> [<a href="https://arxiv.org/pdf/2407.14761">pdf</a>, <a href="https://arxiv.org/format/2407.14761">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"> L2O-$g^{\dagger}$: Learning to Optimize Parameterized Quantum Circuits with Fubini-Study Metric Tensor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yu-Chao Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Goan%2C+H">Hsi-Sheng Goan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2407.14761v2-abstract-short" style="display: inline;"> Before the advent of fault-tolerant quantum computers, variational quantum algorithms (VQAs) play a crucial role in noisy intermediate-scale quantum (NISQ) machines. Conventionally, the optimization of VQAs predominantly relies on manually designed optimizers. However, learning to optimize (L2O) demonstrates impressive performance by training small neural networks to replace handcrafted optimizers… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.14761v2-abstract-full').style.display = 'inline'; document.getElementById('2407.14761v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.14761v2-abstract-full" style="display: none;"> Before the advent of fault-tolerant quantum computers, variational quantum algorithms (VQAs) play a crucial role in noisy intermediate-scale quantum (NISQ) machines. Conventionally, the optimization of VQAs predominantly relies on manually designed optimizers. However, learning to optimize (L2O) demonstrates impressive performance by training small neural networks to replace handcrafted optimizers. In our work, we propose L2O-$g^{\dagger}$, a $\textit{quantum-aware}$ learned optimizer that leverages the Fubini-Study metric tensor ($g^{\dagger}$) and long short-term memory networks. We theoretically derive the update equation inspired by the lookahead optimizer and incorporate the quantum geometry of the optimization landscape in the learned optimizer to balance fast convergence and generalization. Empirically, we conduct comprehensive experiments across a range of VQA problems. Our results demonstrate that L2O-$g^{\dagger}$ not only outperforms the current SOTA hand-designed optimizer without any hyperparameter tuning but also shows strong out-of-distribution generalization compared to previous L2O optimizers. We achieve this by training L2O-$g^{\dagger}$ on just a single generic PQC instance. Our novel $\textit{quantum-aware}$ learned optimizer, L2O-$g^{\dagger}$, presents an advancement in addressing the challenges of VQAs, making it a valuable tool in the NISQ era. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.14761v2-abstract-full').style.display = 'none'; document.getElementById('2407.14761v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 24 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 20 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">19 pages; Code available at https://github.com/Physics-Morris/L2O-g; reference added</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.11454">arXiv:2407.11454</a> <span> [<a href="https://arxiv.org/pdf/2407.11454">pdf</a>, <a href="https://arxiv.org/format/2407.11454">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Cryptography and Security">cs.CR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Distributed, Parallel, and Cluster Computing">cs.DC</span> </div> </div> <p class="title is-5 mathjax"> Cloud-based Semi-Quantum Money </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Y">Yichi Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Jin%2C+S">Siyuan Jin</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yuhan Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Zeng%2C+B">Bei Zeng</a>, <a href="/search/quant-ph?searchtype=author&query=Shao%2C+Q">Qiming Shao</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2407.11454v1-abstract-short" style="display: inline;"> In the 1970s, Wiesner introduced the concept of quantum money, where quantum states generated according to specific rules function as currency. These states circulate among users with quantum resources through quantum channels or face-to-face interactions. Quantum mechanics grants quantum money physical-level unforgeability but also makes minting, storing, and circulating it significantly challeng… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.11454v1-abstract-full').style.display = 'inline'; document.getElementById('2407.11454v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.11454v1-abstract-full" style="display: none;"> In the 1970s, Wiesner introduced the concept of quantum money, where quantum states generated according to specific rules function as currency. These states circulate among users with quantum resources through quantum channels or face-to-face interactions. Quantum mechanics grants quantum money physical-level unforgeability but also makes minting, storing, and circulating it significantly challenging. Currently, quantum computers capable of minting and preserving quantum money have not yet emerged, and existing quantum channels are not stable enough to support the efficient transmission of quantum states for quantum money, limiting its practicality. Semi-quantum money schemes support fully classical transactions and complete classical banks, reducing dependence on quantum resources and enhancing feasibility. To further minimize the system's reliance on quantum resources, we propose a cloud-based semi-quantum money (CSQM) scheme. This scheme relies only on semi-honest third-party quantum clouds, while the rest of the system remains entirely classical. We also discuss estimating the computational power required by the quantum cloud for the scheme and conduct a security analysis. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.11454v1-abstract-full').style.display = 'none'; document.getElementById('2407.11454v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.04512">arXiv:2407.04512</a> <span> [<a href="https://arxiv.org/pdf/2407.04512">pdf</a>, <a href="https://arxiv.org/format/2407.04512">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> </div> </div> <p class="title is-5 mathjax"> Entropy Computing: A Paradigm for Optimization in an Open Quantum System </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Nguyen%2C+L">Lac Nguyen</a>, <a href="/search/quant-ph?searchtype=author&query=Miri%2C+M">Mohammad-Ali Miri</a>, <a href="/search/quant-ph?searchtype=author&query=Rupert%2C+R+J">R. Joseph Rupert</a>, <a href="/search/quant-ph?searchtype=author&query=Dyk%2C+W">Wesley Dyk</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+S">Sam Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Vrahoretis%2C+N">Nick Vrahoretis</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+I">Irwin Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Begliarbekov%2C+M">Milan Begliarbekov</a>, <a href="/search/quant-ph?searchtype=author&query=Chancellor%2C+N">Nicholas Chancellor</a>, <a href="/search/quant-ph?searchtype=author&query=Chukwu%2C+U">Uchenna Chukwu</a>, <a href="/search/quant-ph?searchtype=author&query=Mahamuni%2C+P">Pranav Mahamuni</a>, <a href="/search/quant-ph?searchtype=author&query=Martinez-Delgado%2C+C">Cesar Martinez-Delgado</a>, <a href="/search/quant-ph?searchtype=author&query=Haycraft%2C+D">David Haycraft</a>, <a href="/search/quant-ph?searchtype=author&query=Spear%2C+C">Carrie Spear</a>, <a href="/search/quant-ph?searchtype=author&query=Campanelli%2C+M">Mark Campanelli</a>, <a href="/search/quant-ph?searchtype=author&query=Huffman%2C+R">Russell Huffman</a>, <a href="/search/quant-ph?searchtype=author&query=Sua%2C+Y+M">Yong Meng Sua</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yuping Huang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2407.04512v1-abstract-short" style="display: inline;"> Modern quantum technologies using matter are designed as closed quantum systems to isolate them from interactions with the environment. This design paradigm greatly constrains the scalability and limits practical implementation of such systems. Here, we introduce a novel computing paradigm, entropy computing, that works by conditioning a quantum reservoir thereby enabling the stabilization of a gr… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.04512v1-abstract-full').style.display = 'inline'; document.getElementById('2407.04512v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.04512v1-abstract-full" style="display: none;"> Modern quantum technologies using matter are designed as closed quantum systems to isolate them from interactions with the environment. This design paradigm greatly constrains the scalability and limits practical implementation of such systems. Here, we introduce a novel computing paradigm, entropy computing, that works by conditioning a quantum reservoir thereby enabling the stabilization of a ground state. In this work, we experimentally demonstrate the feasibility of entropy computing by building a hybrid photonic-electronic computer that uses measurement-based feedback to solve non-convex optimization problems. The system functions by using temporal photonic modes to create qudits in order to encode probability amplitudes in the time-frequency degree of freedom of a photon. This scheme, when coupled with electronic interconnects, allows us to encode an arbitrary Hamiltonian into the system and solve non-convex continuous variables and combinatorial optimization problems. We show that the proposed entropy computing paradigm can act as a scalable and versatile platform for tackling a large range of NP-hard optimization problems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.04512v1-abstract-full').style.display = 'none'; document.getElementById('2407.04512v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2406.09502">arXiv:2406.09502</a> <span> [<a href="https://arxiv.org/pdf/2406.09502">pdf</a>, <a href="https://arxiv.org/format/2406.09502">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Disordered Systems and Neural Networks">cond-mat.dis-nn</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="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"> Universal scaling of Green's functions in disordered non-Hermitian systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yin-Quan Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Hu%2C+Y">Yu-Min Hu</a>, <a href="/search/quant-ph?searchtype=author&query=Xue%2C+W">Wen-Tan Xue</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zhong Wang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2406.09502v1-abstract-short" style="display: inline;"> The competition between non-Hermitian skin effect and Anderson localization leads to various intriguing phenomena concerning spectrums and wavefunctions. Here, we study the linear response of disordered non-Hermitian systems, which is precisely described by the Green's function. We find that the average maximum value of matrix elements of Green's functions, which quantifies the maximum response ag… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.09502v1-abstract-full').style.display = 'inline'; document.getElementById('2406.09502v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2406.09502v1-abstract-full" style="display: none;"> The competition between non-Hermitian skin effect and Anderson localization leads to various intriguing phenomena concerning spectrums and wavefunctions. Here, we study the linear response of disordered non-Hermitian systems, which is precisely described by the Green's function. We find that the average maximum value of matrix elements of Green's functions, which quantifies the maximum response against an external perturbation, exhibits different phases characterized by different scaling behaviors with respect to the system size. Whereas the exponential-growth phase is also seen in the translation-invariant systems, the algebraic-growth phase is unique to disordered non-Hermitian systems. We explain the findings using the large deviation theory, which provides analytical insights into the algebraic scaling factors of non-Hermitian disordered Green's functions. Furthermore, we show that these scaling behaviors can be observed in the steady states of disordered open quantum systems, offering a quantum-mechanical avenue for their experimental detection. Our work highlights an unexpected interplay between non-Hermitian skin effect and Anderson localization. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.09502v1-abstract-full').style.display = 'none'; document.getElementById('2406.09502v1-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 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">6+3 pages, 3+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/2406.08314">arXiv:2406.08314</a> <span> [<a href="https://arxiv.org/pdf/2406.08314">pdf</a>, <a href="https://arxiv.org/format/2406.08314">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Chemical Physics">physics.chem-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey 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"> GPU-accelerated Auxiliary-field quantum Monte Carlo with multi-Slater determinant trial states </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yifei Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Z">Zhen Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Pham%2C+H+Q">Hung Q. Pham</a>, <a href="/search/quant-ph?searchtype=author&query=Lv%2C+D">Dingshun Lv</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="2406.08314v1-abstract-short" style="display: inline;"> The accuracy of phaseless auxiliary-field quantum Monte Carlo (ph-AFQMC) can be systematically improved with better trial states. Using multi-Slater determinant trial states, ph-AFQMC has the potential to faithfully treat strongly correlated systems, while balancing the static and dynamical correlations on an equal footing. This preprint presents an implementation and application of graphics proce… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.08314v1-abstract-full').style.display = 'inline'; document.getElementById('2406.08314v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2406.08314v1-abstract-full" style="display: none;"> The accuracy of phaseless auxiliary-field quantum Monte Carlo (ph-AFQMC) can be systematically improved with better trial states. Using multi-Slater determinant trial states, ph-AFQMC has the potential to faithfully treat strongly correlated systems, while balancing the static and dynamical correlations on an equal footing. This preprint presents an implementation and application of graphics processing unit-accelerated ph-AFQMC, for multi-Slater determinant trial wavefunctions (GPU-accelerated MSD-AFQMC), to enable efficient simulation of large-scale, strongly correlated systems. This approach allows for nearly-exact computation of ground state energies in multi-reference systems. Our GPU-accelerated MSD-AFQMC is implemented in the open-source code \texttt{ipie}, a Python-based AFQMC package [\textit{J. Chem. Theory Comput.}, 2022, 19(1): 109-121]. We benchmark the performance of the GPU code on transition-metal clusters like [Cu$_2$O$_2$]$^{2+}$ and [Fe$_2$S$_2$(SCH$_3$)]$^{2-}$. The GPU code achieves at least sixfold speedup in both cases, comparing the timings of a single A100 GPU to that of a 32-CPU node. For [Fe$_2$S$_2$(SCH$_3$)]$^{2-}$, we demonstrate that our GPU MSD-AFQMC can recover the dynamical correlation necessary for chemical accuracy with an MSD trial, despite the large number of determinants required ($>10^5$). Our work significantly enhances the efficiency of MSD-AFQMC calculations for large, strongly correlated molecules by utilizing GPUs, offering a promising path for exploring the electronic structure of transition metal complexes. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.08314v1-abstract-full').style.display = 'none'; document.getElementById('2406.08314v1-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">6 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/2406.05399">arXiv:2406.05399</a> <span> [<a href="https://arxiv.org/pdf/2406.05399">pdf</a>, <a href="https://arxiv.org/ps/2406.05399">ps</a>, <a href="https://arxiv.org/format/2406.05399">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Statistical Mechanics">cond-mat.stat-mech</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> High-precision simulation of finite-size thermalizing systems at long times </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yichen Huang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2406.05399v1-abstract-short" style="display: inline;"> To simulate thermalizing systems at long times, the most straightforward approach is to calculate the thermal properties at the corresponding energy. In a quantum many-body system of size $N$, for local observables and many initial states, this approach has an error of $O(1/N)$, which is reminiscent of the finite-size error of the equivalence of ensembles. In this paper, we propose a simple and ef… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.05399v1-abstract-full').style.display = 'inline'; document.getElementById('2406.05399v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2406.05399v1-abstract-full" style="display: none;"> To simulate thermalizing systems at long times, the most straightforward approach is to calculate the thermal properties at the corresponding energy. In a quantum many-body system of size $N$, for local observables and many initial states, this approach has an error of $O(1/N)$, which is reminiscent of the finite-size error of the equivalence of ensembles. In this paper, we propose a simple and efficient numerical method so that the simulation error is of higher order in $1/N$. This finite-size error scaling is proved by assuming the eigenstate thermalization hypothesis. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.05399v1-abstract-full').style.display = 'none'; document.getElementById('2406.05399v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 8 June, 2024; <span class="has-text-black-bis has-text-weight-semibold">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/2406.03502">arXiv:2406.03502</a> <span> [<a href="https://arxiv.org/pdf/2406.03502">pdf</a>, <a href="https://arxiv.org/format/2406.03502">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Optimization and Control">math.OC</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-Inspired Mean Field Probabilistic Model for Combinatorial Optimization Problems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yuhan Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Jin%2C+S">Siyuan Jin</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Y">Yichi Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Pan%2C+L">Ling Pan</a>, <a href="/search/quant-ph?searchtype=author&query=Shao%2C+Q">Qiming Shao</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2406.03502v1-abstract-short" style="display: inline;"> Combinatorial optimization problems are pivotal across many fields. Among these, Quadratic Unconstrained Binary Optimization (QUBO) problems, central to fields like portfolio optimization, network design, and computational biology, are NP-hard and require exponential computational resources. To address these challenges, we develop a novel Quantum-Inspired Mean Field (QIMF) probabilistic model that… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.03502v1-abstract-full').style.display = 'inline'; document.getElementById('2406.03502v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2406.03502v1-abstract-full" style="display: none;"> Combinatorial optimization problems are pivotal across many fields. Among these, Quadratic Unconstrained Binary Optimization (QUBO) problems, central to fields like portfolio optimization, network design, and computational biology, are NP-hard and require exponential computational resources. To address these challenges, we develop a novel Quantum-Inspired Mean Field (QIMF) probabilistic model that approximates solutions to QUBO problems with enhanced accuracy and efficiency. The QIMF model draws inspiration from quantum measurement principles and leverages the mean field probabilistic model. We incorporate a measurement grouping technique and an amplitude-based shot allocation strategy, both critical for optimizing cost functions with a polynomial speedup over traditional methods. Our extensive empirical studies demonstrate significant improvements in solution evaluation for large-scale problems of portfolio selection, the weighted maxcut problem, and the Ising model. Specifically, using S&P 500 data from 2022 and 2023, QIMF improves cost values by 152.8% and 12.5%, respectively, compared to the state-of-the-art baselines. Furthermore, when evaluated on increasingly larger datasets for QUBO problems, QIMF's scalability demonstrates its potential for large-scale QUBO challenges. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.03502v1-abstract-full').style.display = 'none'; document.getElementById('2406.03502v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 31 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 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/2406.02236">arXiv:2406.02236</a> <span> [<a href="https://arxiv.org/pdf/2406.02236">pdf</a>, <a href="https://arxiv.org/format/2406.02236">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> </div> </div> <p class="title is-5 mathjax"> Demonstration of superior communication through thermodynamically free channels in an optical quantum switch </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Tang%2C+H">Hao Tang</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Y">Yu Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Hu%2C+X">Xiao-Min Hu</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yun-Feng Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+B">Bi-Heng Liu</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="2406.02236v1-abstract-short" style="display: inline;"> The release of causal structure of physical events from a well-defined order to an indefinite one stimulates remarkable enhancements in various quantum information tasks. Some of these advantages, however, are questioned for the ambiguous role of the control system in the quantum switch that is an experimentally realized process with indefinite causal structure. In communications, for example, not… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.02236v1-abstract-full').style.display = 'inline'; document.getElementById('2406.02236v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2406.02236v1-abstract-full" style="display: none;"> The release of causal structure of physical events from a well-defined order to an indefinite one stimulates remarkable enhancements in various quantum information tasks. Some of these advantages, however, are questioned for the ambiguous role of the control system in the quantum switch that is an experimentally realized process with indefinite causal structure. In communications, for example, not only the superposition of alternative causal orders, but also the superposition of alternative trajectories can accelerate information transmissions. Here, we follow the proposal of Liu et al. [Phys. Rev. Lett. 129, 230604 (2022)], and examine the information enhancement effect of indefinite causal orders with the toolkit of thermodynamics in a photonic platform. Specifically, we simulate the thermal interaction between a system qubit and two heat baths embedded in a quantum switch by implementing the corresponding switched thermal channels. Although its action on the system qubit only is thermally free, our results suggest that the quantum switch should be seen as a resource when the control qubit is also considered. Moreover, we characterize the non-Markovian property in this scenario by measuring the information backflows from the heat baths to the system qubit. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.02236v1-abstract-full').style.display = 'none'; document.getElementById('2406.02236v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 June, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2405.13369">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/2405.12232">arXiv:2405.12232</a> <span> [<a href="https://arxiv.org/pdf/2405.12232">pdf</a>, <a href="https://arxiv.org/ps/2405.12232">ps</a>, <a href="https://arxiv.org/format/2405.12232">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Chemical Physics">physics.chem-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Charge-transport forecasted via deep learning in the photosystem II reaction center </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+Z">Zi-Ran Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+S">Shun-Cai Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yi-Meng Huang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2405.12232v1-abstract-short" style="display: inline;"> Predicting future physical behavior through the limited theoretical simulation data available is an emerging research paradigm resulted by the integration of artificial intelligence technology and quantum physics. In this work, the charge-transport(CT) behavior was forecasted over a long time by a deep learning model, the long short-term memory (LSTM) network with error threshold training method i… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.12232v1-abstract-full').style.display = 'inline'; document.getElementById('2405.12232v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.12232v1-abstract-full" style="display: none;"> Predicting future physical behavior through the limited theoretical simulation data available is an emerging research paradigm resulted by the integration of artificial intelligence technology and quantum physics. In this work, the charge-transport(CT) behavior was forecasted over a long time by a deep learning model, the long short-term memory (LSTM) network with error threshold training method in the photosynthesis II reaction center (PSII-RC). The theoretical simulation data within 8 fs was fed to the modified LSTM network for training, which brings out a distinct prediction with difference of $10^{-4}$ orders of magnitude over a long time period compared to the collection time for training sets. The results indicate the potential of employing LSTM to reveal the physics governing CT in addition to quantum physical methods. The implications of this work warrant further investigation to fully elucidate the scope and efficacy of LSTM for advancing our understanding of photosynthesis at the molecular scale. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.12232v1-abstract-full').style.display = 'none'; document.getElementById('2405.12232v1-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 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">8 pages, 4 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2405.00150">arXiv:2405.00150</a> <span> [<a href="https://arxiv.org/pdf/2405.00150">pdf</a>, <a href="https://arxiv.org/format/2405.00150">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"> An Invertible All-optical Logic Gate on Chip </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zhan Li</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+J">Jiayang Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Sua%2C+Y">Yongmeng Sua</a>, <a href="/search/quant-ph?searchtype=author&query=Ma%2C+Z">Zhaohui Ma</a>, <a href="/search/quant-ph?searchtype=author&query=Tang%2C+C">Chao Tang</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yu-ping Huang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2405.00150v1-abstract-short" style="display: inline;"> We demonstrate an invertible all-optical gate on chip, with the roles of control and signal switchable by slightly adjusting their relative arrival time at the gate. It is based on quantum Zeno blockade driven by sum-frequency generation in a periodic-poled lithium niobate microring resonator. For two nearly-identical nanosecond pulses, the later arriving pulse is modulated by the earlier arriving… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.00150v1-abstract-full').style.display = 'inline'; document.getElementById('2405.00150v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.00150v1-abstract-full" style="display: none;"> We demonstrate an invertible all-optical gate on chip, with the roles of control and signal switchable by slightly adjusting their relative arrival time at the gate. It is based on quantum Zeno blockade driven by sum-frequency generation in a periodic-poled lithium niobate microring resonator. For two nearly-identical nanosecond pulses, the later arriving pulse is modulated by the earlier arriving one, resulting in 2.4 and 3.9 power extinction between the two, respectively, when their peak power is 1 mW and 2 mW. Our results, while to be improved and enriched, herald a new paradigm of logical gates and circuits for exotic applications. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.00150v1-abstract-full').style.display = 'none'; document.getElementById('2405.00150v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 April, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2404.08429">arXiv:2404.08429</a> <span> [<a href="https://arxiv.org/pdf/2404.08429">pdf</a>, <a href="https://arxiv.org/format/2404.08429">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"> Optimized Quantum Autoencoder </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yibin Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+M">Muchun Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+D+L">D. L. 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="2404.08429v1-abstract-short" style="display: inline;"> Quantum autoencoder (QAE) compresses a bipartite quantum state into its subsystem by a self-checking mechanism. How to characterize the lost information in this process is essential to understand the compression mechanism of QAE\@. Here we investigate how to decrease the lost information in QAE for any input mixed state. We theoretically show that the lost information is the quantum mutual informa… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.08429v1-abstract-full').style.display = 'inline'; document.getElementById('2404.08429v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2404.08429v1-abstract-full" style="display: none;"> Quantum autoencoder (QAE) compresses a bipartite quantum state into its subsystem by a self-checking mechanism. How to characterize the lost information in this process is essential to understand the compression mechanism of QAE\@. Here we investigate how to decrease the lost information in QAE for any input mixed state. We theoretically show that the lost information is the quantum mutual information between the remaining subsystem and the ignorant one, and the encoding unitary transformation is designed to minimize this mutual information. Further more, we show that the optimized unitary transformation can be decomposed as the product of a permutation unitary transformation and a disentanglement unitary transformation, and the permutation unitary transformation can be searched by a regular Young tableau algorithm. Finally we numerically identify that our compression scheme outperforms the quantum variational circuit based QAE\@. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.08429v1-abstract-full').style.display = 'none'; document.getElementById('2404.08429v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 April, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2404.06434">arXiv:2404.06434</a> <span> [<a href="https://arxiv.org/pdf/2404.06434">pdf</a>, <a href="https://arxiv.org/format/2404.06434">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 Graph Optimization Algorithm </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yuhan Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Nugraha%2C+F+P">Ferris Prima Nugraha</a>, <a href="/search/quant-ph?searchtype=author&query=Jin%2C+S">Siyuan Jin</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Y">Yichi Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Zeng%2C+B">Bei Zeng</a>, <a href="/search/quant-ph?searchtype=author&query=Shao%2C+Q">Qiming Shao</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2404.06434v1-abstract-short" style="display: inline;"> Quadratic unconstrained binary optimization (QUBO) tasks are very important in chemistry, finance, job scheduling, and so on, which can be represented using graph structures, with the variables as nodes and the interaction between them as edges. Variational quantum algorithms, especially the Quantum Approximate Optimization Algorithm (QAOA) and its variants, present a promising way, potentially ex… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.06434v1-abstract-full').style.display = 'inline'; document.getElementById('2404.06434v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2404.06434v1-abstract-full" style="display: none;"> Quadratic unconstrained binary optimization (QUBO) tasks are very important in chemistry, finance, job scheduling, and so on, which can be represented using graph structures, with the variables as nodes and the interaction between them as edges. Variational quantum algorithms, especially the Quantum Approximate Optimization Algorithm (QAOA) and its variants, present a promising way, potentially exceeding the capabilities of classical algorithms, for addressing QUBO tasks. However, the possibility of using message-passing machines, inspired by classical graph neural networks, to enhance the power and performance of these quantum algorithms for QUBO tasks was not investigated. This study introduces a novel variational quantum graph optimization algorithm that integrates the message-passing mechanism, which demonstrates significant improvements in performance for solving QUBO problems in terms of resource efficiency and solution precision, compared to QAOA, its variants, and other quantum graph neural networks. Furthermore, in terms of scalability on QUBO tasks, our algorithm shows superior performance compared to QAOA, presenting a substantial advancement in the field of quantum approximate optimization. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.06434v1-abstract-full').style.display = 'none'; document.getElementById('2404.06434v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 9 April, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">11pages,5figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.18263">arXiv:2403.18263</a> <span> [<a href="https://arxiv.org/pdf/2403.18263">pdf</a>, <a href="https://arxiv.org/format/2403.18263">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 - Experiment">hep-ex</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> New Constraints on Exotic Spin-Spin-Velocity-Dependent Interactions with Solid-State Quantum Sensors </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yue Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Liang%2C+H">Hang Liang</a>, <a href="/search/quant-ph?searchtype=author&query=Jiao%2C+M">Man Jiao</a>, <a href="/search/quant-ph?searchtype=author&query=Yu%2C+P">Pei Yu</a>, <a href="/search/quant-ph?searchtype=author&query=Ye%2C+X">Xiangyu Ye</a>, <a href="/search/quant-ph?searchtype=author&query=Xie%2C+Y">Yijin Xie</a>, <a href="/search/quant-ph?searchtype=author&query=Cai%2C+Y">Yi-Fu Cai</a>, <a href="/search/quant-ph?searchtype=author&query=Duan%2C+C">Chang-Kui Duan</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Y">Ya Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Rong%2C+X">Xing Rong</a>, <a href="/search/quant-ph?searchtype=author&query=Du%2C+J">Jiangfeng Du</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2403.18263v1-abstract-short" style="display: inline;"> We report new experimental results on exotic spin-spin-velocity-dependent interactions between electron spins. We designed an elaborate setup that is equipped with two nitrogen-vacancy (NV) ensembles in diamonds. One of the NV ensembles serves as the spin source, while the other functions as the spin sensor. By coherently manipulating the quantum states of two NV ensembles and their relative veloc… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.18263v1-abstract-full').style.display = 'inline'; document.getElementById('2403.18263v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.18263v1-abstract-full" style="display: none;"> We report new experimental results on exotic spin-spin-velocity-dependent interactions between electron spins. We designed an elaborate setup that is equipped with two nitrogen-vacancy (NV) ensembles in diamonds. One of the NV ensembles serves as the spin source, while the other functions as the spin sensor. By coherently manipulating the quantum states of two NV ensembles and their relative velocity at the micrometer scale, we are able to scrutinize exotic spin-spin-velocity-dependent interactions at short force ranges. For a T-violating interaction, $V_6$, new limits on the corresponding coupling coefficient, $f_6$, have been established for the force range shorter than 1 cm. For a P,T-violating interaction, $V_{14}$, new constraints on the corresponding coupling coefficient, $f_{14}$, have been obtained for the force range shorter than 1 km. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.18263v1-abstract-full').style.display = 'none'; document.getElementById('2403.18263v1-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 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/2403.14455">arXiv:2403.14455</a> <span> [<a href="https://arxiv.org/pdf/2403.14455">pdf</a>, <a href="https://arxiv.org/format/2403.14455">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"> Non-Markovian skin effect </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Kuo%2C+P">Po-Chen Kuo</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+S">Shen-Liang Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Lambert%2C+N">Neill Lambert</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+J">Jhen-Dong Lin</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yi-Te Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Nori%2C+F">Franco Nori</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Y">Yueh-Nan 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="2403.14455v2-abstract-short" style="display: inline;"> The Liouvillian skin effect and the non-Hermitian skin effect have both been used to explain the localization of eigenmodes near system boundaries, though the former is arguably more accurate in some regimes due to its incorporation of quantum jumps. However, these frameworks predominantly focus on weak Markovian interactions, neglecting the potentially crucial role of memory effects. To address t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.14455v2-abstract-full').style.display = 'inline'; document.getElementById('2403.14455v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.14455v2-abstract-full" style="display: none;"> The Liouvillian skin effect and the non-Hermitian skin effect have both been used to explain the localization of eigenmodes near system boundaries, though the former is arguably more accurate in some regimes due to its incorporation of quantum jumps. However, these frameworks predominantly focus on weak Markovian interactions, neglecting the potentially crucial role of memory effects. To address this, we investigate, utilizing the powerful hierarchical equations of motion method, how a non-Markovian environment can modify the Liouvillian skin effect. We demonstrate that a non-Markovian environment can induce a ``thick skin effect", where the skin mode broadens and shifts into the bulk. {We further identify that the skin-mode quantum coherence can only be generated when the coupling contains counter-rotating terms}, leading to the coherence-delocalization and oscillatory relaxation with a characteristic linear scaling with system size. Remarkably, both the skin-mode and steady-state coherence exhibit resistance to decoherence from additional environmental noise. These findings highlight the profound impact of system-bath correlations on relaxation and localization, revealing unique phenomena beyond conventional Markovian approximations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.14455v2-abstract-full').style.display = 'none'; document.getElementById('2403.14455v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 23 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 21 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">15 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/2403.09339">arXiv:2403.09339</a> <span> [<a href="https://arxiv.org/pdf/2403.09339">pdf</a>, <a href="https://arxiv.org/format/2403.09339">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1364/OPTICA.520697">10.1364/OPTICA.520697 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Field test of mode-pairing quantum key distribution </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+H">Hao-Tao Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yizhi Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Pan%2C+W">Wen-Xin Pan</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+C">Chao-Wu Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Tang%2C+J">Jianjun Tang</a>, <a href="/search/quant-ph?searchtype=author&query=He%2C+H">Hong He</a>, <a href="/search/quant-ph?searchtype=author&query=Cheng%2C+M">Ming Cheng</a>, <a href="/search/quant-ph?searchtype=author&query=Jin%2C+X">Xiandu Jin</a>, <a href="/search/quant-ph?searchtype=author&query=Zou%2C+M">Mi Zou</a>, <a href="/search/quant-ph?searchtype=author&query=Tang%2C+S">Shibiao Tang</a>, <a href="/search/quant-ph?searchtype=author&query=Ma%2C+X">Xiongfeng Ma</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+T">Teng-Yun Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Pan%2C+J">Jian-Wei Pan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2403.09339v1-abstract-short" style="display: inline;"> Quantum key distribution is a cornerstone of quantum technology, offering information-theoretical secure keys for remote parties. With many quantum communication networks established globally, the mode-pairing protocol stands out for its efficacy over inter-city distances using simple setups, emerging as a promising solution. In this study, we employ the mode-pairing scheme into existing inter-cit… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.09339v1-abstract-full').style.display = 'inline'; document.getElementById('2403.09339v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.09339v1-abstract-full" style="display: none;"> Quantum key distribution is a cornerstone of quantum technology, offering information-theoretical secure keys for remote parties. With many quantum communication networks established globally, the mode-pairing protocol stands out for its efficacy over inter-city distances using simple setups, emerging as a promising solution. In this study, we employ the mode-pairing scheme into existing inter-city fiber links, conducting field tests across distances ranging from tens to about a hundred kilometers. Our system achieves a key rate of $1.217$ kbit/s in a $195.85$ km symmetric link and $3.089$ kbit/s in a $127.92$ km asymmetric link without global phase locking. The results demonstrate that the mode-pairing protocol can achieve key rates comparable to those of a single quantum link between two trusted nodes on the Beijing-Shanghai backbone line, effectively reducing the need for half of the trusted nodes. These field tests confirm the mode-pairing scheme's adaptability, efficiency, and practicality, positioning it as a highly suitable protocol for quantum networks. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.09339v1-abstract-full').style.display = 'none'; document.getElementById('2403.09339v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">15 pages, 5 figures, 6 tables</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Optica 11, 883-888 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2401.15428">arXiv:2401.15428</a> <span> [<a href="https://arxiv.org/pdf/2401.15428">pdf</a>, <a href="https://arxiv.org/format/2401.15428">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 genuine quantum nonlocality in the triangle network </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wang%2C+N">Ning-Ning Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+C">Chao Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Cao%2C+H">Huan Cao</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+K">Kai Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+B">Bi-Heng Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yun-Feng Huang</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=Gisin%2C+N">Nicolas Gisin</a>, <a href="/search/quant-ph?searchtype=author&query=Kriv%C3%A1chy%2C+T">Tam谩s Kriv谩chy</a>, <a href="/search/quant-ph?searchtype=author&query=Renou%2C+M">Marc-Olivier Renou</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="2401.15428v1-abstract-short" style="display: inline;"> In the last decade, it was understood that quantum networks involving several independent sources of entanglement which are distributed and measured by several parties allowed for completely novel forms of nonclassical quantum correlations, when entangled measurements are performed. Here, we experimentally obtain quantum correlations in a triangle network structure, and provide solid evidence of i… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.15428v1-abstract-full').style.display = 'inline'; document.getElementById('2401.15428v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2401.15428v1-abstract-full" style="display: none;"> In the last decade, it was understood that quantum networks involving several independent sources of entanglement which are distributed and measured by several parties allowed for completely novel forms of nonclassical quantum correlations, when entangled measurements are performed. Here, we experimentally obtain quantum correlations in a triangle network structure, and provide solid evidence of its nonlocality. Specifically, we first obtain the elegant distribution proposed in (Entropy 21, 325) by performing a six-photon experiment. Then, we justify its nonlocality based on machine learning tools to estimate the distance of the experimentally obtained correlation to the local set, and through the violation of a family of conjectured inequalities tailored for the triangle network. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.15428v1-abstract-full').style.display = 'none'; document.getElementById('2401.15428v1-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 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/2401.10697">arXiv:2401.10697</a> <span> [<a href="https://arxiv.org/pdf/2401.10697">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"> Reconfigurable entanglement distribution network based on pump management of spontaneous four-wave mixing source </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Liu%2C+J">Jingyuan Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+D">Dongning Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Jin%2C+Z">Zhanping Jin</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+Z">Zhihao Lin</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+H">Hao Li</a>, <a href="/search/quant-ph?searchtype=author&query=You%2C+L">Lixing You</a>, <a href="/search/quant-ph?searchtype=author&query=Feng%2C+X">Xue Feng</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+F">Fang Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Cui%2C+K">Kaiyu Cui</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yidong Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+W">Wei Zhang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2401.10697v1-abstract-short" style="display: inline;"> Leveraging the unique properties of quantum entanglement, quantum entanglement distribution networks support multiple quantum information applications and are essential to the development of quantum networks. However, its practical implementation poses significant challenges to network scalability and flexibility. In this work, we propose a novel reconfigurable entanglement distribution network ba… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.10697v1-abstract-full').style.display = 'inline'; document.getElementById('2401.10697v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2401.10697v1-abstract-full" style="display: none;"> Leveraging the unique properties of quantum entanglement, quantum entanglement distribution networks support multiple quantum information applications and are essential to the development of quantum networks. However, its practical implementation poses significant challenges to network scalability and flexibility. In this work, we propose a novel reconfigurable entanglement distribution network based on tunable multi-pump excitation of a spontaneous four-wave mixing (SFWM) source and a time-sharing method. We characterize the two-photon correlation under different pump conditions to demonstrate the effect of pump degenerate and pump non-degenerate SFWM processes on the two-photon correlation, and its tunability. Then as a benchmark application, a 10-user fully-connected quantum key distribution (QKD) network is established in a time-sharing way with triple pump lights. Each user receives one frequency channel thus it shows a linear scaling between the number of frequency channels and the user number in despite of the network topology. Our results thus provide a promising networking scheme for large-scale entanglement distribution networks owing to its scalability, functionality, and reconfigurability. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.10697v1-abstract-full').style.display = 'none'; document.getElementById('2401.10697v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 19 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">15 pages, 6 figures,</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2401.00454">arXiv:2401.00454</a> <span> [<a href="https://arxiv.org/pdf/2401.00454">pdf</a>, <a href="https://arxiv.org/format/2401.00454">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Computational Complexity">cs.CC</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 and Classical Communication Complexity of Permutation-Invariant Functions </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Guan%2C+Z">Ziyi Guan</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yunqi Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Yao%2C+P">Penghui Yao</a>, <a href="/search/quant-ph?searchtype=author&query=Ye%2C+Z">Zekun Ye</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="2401.00454v1-abstract-short" style="display: inline;"> This paper gives a nearly tight characterization of the quantum communication complexity of the permutation-invariant Boolean functions. With such a characterization, we show that the quantum and randomized communication complexity of the permutation-invariant Boolean functions are quadratically equivalent (up to a logarithmic factor). Our results extend a recent line of research regarding query c… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.00454v1-abstract-full').style.display = 'inline'; document.getElementById('2401.00454v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2401.00454v1-abstract-full" style="display: none;"> This paper gives a nearly tight characterization of the quantum communication complexity of the permutation-invariant Boolean functions. With such a characterization, we show that the quantum and randomized communication complexity of the permutation-invariant Boolean functions are quadratically equivalent (up to a logarithmic factor). Our results extend a recent line of research regarding query complexity \cite{AA14, Cha19, BCG+20} to communication complexity, showing symmetry prevents exponential quantum speedups. Furthermore, we show the Log-rank Conjecture holds for any non-trivial total permutation-invariant Boolean function. Moreover, we establish a relationship between the quantum/classical communication complexity and the approximate rank of permutation-invariant Boolean functions. This implies the correctness of the Log-approximate-rank Conjecture for permutation-invariant Boolean functions in both randomized and quantum settings (up to a logarithmic factor). <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.00454v1-abstract-full').style.display = 'none'; document.getElementById('2401.00454v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 31 December, 2023; <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">accepted in STACS 2024</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2312.12758">arXiv:2312.12758</a> <span> [<a href="https://arxiv.org/pdf/2312.12758">pdf</a>, <a href="https://arxiv.org/format/2312.12758">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Atomic Physics">physics.atom-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> </div> </div> <p class="title is-5 mathjax"> Observation of Highly Correlated Ultrabright Biphotons Through Increased Atomic Ensemble Density in Spontaneous Four-Wave Mixing </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Shiu%2C+J">Jiun-Shiuan Shiu</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+Z">Zi-Yu Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Cheng%2C+C">Chin-Yao Cheng</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yu-Chiao Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Yu%2C+I+A">Ite A. Yu</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Y">Ying-Cheng Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chuu%2C+C">Chih-Sung Chuu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+C">Che-Ming Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+S">Shiang-Yu Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Y">Yong-Fan 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="2312.12758v3-abstract-short" style="display: inline;"> The pairing ratio, a crucial metric assessing a biphoton source's ability to generate correlated photon pairs, remains underexplored despite theoretical predictions. This study presents experimental findings on the pairing ratio, utilizing a double-$螞$ spontaneous four-wave mixing biphoton source in cold atoms. At an optical depth (OD) of 20, we achieved an ultrahigh biphoton generation rate of up… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.12758v3-abstract-full').style.display = 'inline'; document.getElementById('2312.12758v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2312.12758v3-abstract-full" style="display: none;"> The pairing ratio, a crucial metric assessing a biphoton source's ability to generate correlated photon pairs, remains underexplored despite theoretical predictions. This study presents experimental findings on the pairing ratio, utilizing a double-$螞$ spontaneous four-wave mixing biphoton source in cold atoms. At an optical depth (OD) of 20, we achieved an ultrahigh biphoton generation rate of up to $1.3\times10^7$ per second, with a successful pairing ratio of $61\%$. Increasing the OD to 120 significantly improved the pairing ratio to $89\%$, while maintaining a consistent biphoton generation rate. This achievement, marked by high generation rates and robust biphoton pairing, holds great promise for advancing efficiency in quantum communication and information processing. Additionally, in a scenario with a lower biphoton generation rate of $5.0 \times 10^4$ per second, we attained an impressive signal-to-background ratio of 241 for the biphoton wavepacket, surpassing the Cauchy-Schwarz criterion by approximately $1.5\times10^4$ times. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.12758v3-abstract-full').style.display = 'none'; document.getElementById('2312.12758v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 February, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 19 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">Main text: 6 pages, 4 figures; Supplemental material: 12 pages, 2 figure, 1 table</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2312.09372">arXiv:2312.09372</a> <span> [<a href="https://arxiv.org/pdf/2312.09372">pdf</a>, <a href="https://arxiv.org/format/2312.09372">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> </div> <div 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.133.020801">10.1103/PhysRevLett.133.020801 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Vacuum Beam Guide for Large-Scale Quantum Networks </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yuexun Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Salces--Carcoba%2C+F">Francisco Salces--Carcoba</a>, <a href="/search/quant-ph?searchtype=author&query=Adhikari%2C+R+X">Rana X Adhikari</a>, <a href="/search/quant-ph?searchtype=author&query=Safavi-Naeini%2C+A+H">Amir H. Safavi-Naeini</a>, <a href="/search/quant-ph?searchtype=author&query=Jiang%2C+L">Liang Jiang</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="2312.09372v3-abstract-short" style="display: inline;"> The vacuum beam guide (VBG) presents a completely different solution for quantum channels to overcome the limitations of existing fiber and satellite technologies for long-distance quantum communication. With an array of aligned lenses spaced kilometers apart, the VBG offers ultra-high transparency over a wide range of optical wavelengths. With realistic parameters, the VBG can outperform the best… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.09372v3-abstract-full').style.display = 'inline'; document.getElementById('2312.09372v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2312.09372v3-abstract-full" style="display: none;"> The vacuum beam guide (VBG) presents a completely different solution for quantum channels to overcome the limitations of existing fiber and satellite technologies for long-distance quantum communication. With an array of aligned lenses spaced kilometers apart, the VBG offers ultra-high transparency over a wide range of optical wavelengths. With realistic parameters, the VBG can outperform the best fiber by three orders of magnitude in terms of attenuation rate. Consequently, the VBG can enable long-range quantum communication over thousands of kilometers with quantum channel capacity beyond $10^{13}$ qubit/sec, orders of magnitude higher than the state-of-the-art quantum satellite communication rate. Remarkably, without relying on quantum repeaters, the VBG can provide a ground-based, low-loss, high-bandwidth quantum channel that enables novel distributed quantum information applications for computing, communication, and sensing. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.09372v3-abstract-full').style.display = 'none'; document.getElementById('2312.09372v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 9 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 14 December, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2023. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2312.03279">arXiv:2312.03279</a> <span> [<a href="https://arxiv.org/pdf/2312.03279">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 Fusion of Independent Networks Based on Multi-user Entanglement Swapping </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yiwen Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+Y">Yilin Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+H">Hao Li</a>, <a href="/search/quant-ph?searchtype=author&query=Qiu%2C+J">Jing Qiu</a>, <a href="/search/quant-ph?searchtype=author&query=Qi%2C+Z">Zhantong Qi</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+J">Jiayu Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Y">Yuting Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yuanhua Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zheng%2C+Y">Yuanlin Zheng</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+X">Xianfeng 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="2312.03279v1-abstract-short" style="display: inline;"> With the advance development in quantum science, constructing a large-scale quantum network has become a hot area of future quantum information technology. Future quantum networks promise to enable many fantastic applications and will unlock fundamentally new technologies in information security and large-scale computation. The future quantum internet is required to connect quantum information pro… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.03279v1-abstract-full').style.display = 'inline'; document.getElementById('2312.03279v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2312.03279v1-abstract-full" style="display: none;"> With the advance development in quantum science, constructing a large-scale quantum network has become a hot area of future quantum information technology. Future quantum networks promise to enable many fantastic applications and will unlock fundamentally new technologies in information security and large-scale computation. The future quantum internet is required to connect quantum information processors to achieve unparalleled capabilities in secret communication and enable quantum communication between any two points on Earth. However, the existing quantum networks are basically constructed to realize the communication between the end users in their own networks. How to bridge different independent networks to form a fully-connected quantum internet becomes a pressing challenge for future networks. Here, we demonstrate the quantum fusion of two independent networks for the first time based on multiuser entanglement swapping, to merge two 10-user networks into a larger network with 18 users in quantum correlation layer. By performing the Bell state measurement between two nonneighboring nodes, the users from different networks can establish entanglement and ultimately every pair of the 18 users are able to communicate with each other using the swapped states. Our approach opens attractive opportunities for the establishment of quantum entanglement between remote nodes in different networks, which facilitates versatile quantum information interconnects and has great application in constructing large-scale intercity quantum communication networks. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.03279v1-abstract-full').style.display = 'none'; document.getElementById('2312.03279v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 December, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2023. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2311.18293">arXiv:2311.18293</a> <span> [<a href="https://arxiv.org/pdf/2311.18293">pdf</a>, <a href="https://arxiv.org/ps/2311.18293">ps</a>, <a href="https://arxiv.org/format/2311.18293">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Statistical Mechanics">cond-mat.stat-mech</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Dynamical relaxation of a long-range XY chain </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yu-Huang Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Zou%2C+Y">Yin-Tao Zou</a>, <a href="/search/quant-ph?searchtype=author&query=Ding%2C+C">Chengxiang Ding</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="2311.18293v2-abstract-short" style="display: inline;"> We study the universal real-time relaxation behaviors of a long-range quantum XY chain following a quench. Our research includes both the noncritical and critical quench. In the case of noncritical quench, i.e., neither the initial state nor the postquench Hamiltonian is at a critical point of equilibrium phase transition, a quench to the commensurate phase or incommensurate phase gives a scaling… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.18293v2-abstract-full').style.display = 'inline'; document.getElementById('2311.18293v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2311.18293v2-abstract-full" style="display: none;"> We study the universal real-time relaxation behaviors of a long-range quantum XY chain following a quench. Our research includes both the noncritical and critical quench. In the case of noncritical quench, i.e., neither the initial state nor the postquench Hamiltonian is at a critical point of equilibrium phase transition, a quench to the commensurate phase or incommensurate phase gives a scaling of $t^{-3/2}$ or $t^{-1/2}$, respectively, which is the same as the counterpart of the short-range XY model. However, for a quench to the boundary line between the commensurate and incommensurate phases, the scaling law $t^{-渭}$ may be different from the $t^{-3/4}$ law of the counterpart of the short-range model. More interestingly, the decaying exponent $渭$ may depend on the choice of the parameters of the postquench Hamiltonian because of the different asymptotic behaviors of the energy spectrum. Furthermore, in certain cases, the scaling behavior may be outside the range of predictions made by the stationary phase approximation, because an inflection point emerges in the energy spectrum. For the critical quench, i.e., the initial state or the postquench Hamiltonian is at a critical point of equilibrium phase transition, the aforementioned scaling law $t^{-渭}$ may be changed because of the gap-closing property of the energy spectrum of the critical point. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.18293v2-abstract-full').style.display = 'none'; document.getElementById('2311.18293v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 3 December, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 30 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">8 pages, 8 figures. arXiv admin note: text overlap with arXiv:2305.00160</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2311.09567">arXiv:2311.09567</a> <span> [<a href="https://arxiv.org/pdf/2311.09567">pdf</a>, <a href="https://arxiv.org/format/2311.09567">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41467-024-52010-4">10.1038/s41467-024-52010-4 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Entangling gates on degenerate spin qubits dressed by a global field </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Hansen%2C+I">Ingvild Hansen</a>, <a href="/search/quant-ph?searchtype=author&query=Seedhouse%2C+A+E">Amanda E. Seedhouse</a>, <a href="/search/quant-ph?searchtype=author&query=Serrano%2C+S">Santiago Serrano</a>, <a href="/search/quant-ph?searchtype=author&query=Nickl%2C+A">Andreas Nickl</a>, <a href="/search/quant-ph?searchtype=author&query=Feng%2C+M">MengKe Feng</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+J+Y">Jonathan Y. Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Tanttu%2C+T">Tuomo Tanttu</a>, <a href="/search/quant-ph?searchtype=author&query=Stuyck%2C+N+D">Nard Dumoulin Stuyck</a>, <a href="/search/quant-ph?searchtype=author&query=Lim%2C+W+H">Wee Han Lim</a>, <a href="/search/quant-ph?searchtype=author&query=Hudson%2C+F+E">Fay E. Hudson</a>, <a href="/search/quant-ph?searchtype=author&query=Itoh%2C+K+M">Kohei M. Itoh</a>, <a href="/search/quant-ph?searchtype=author&query=Saraiva%2C+A">Andre Saraiva</a>, <a href="/search/quant-ph?searchtype=author&query=Laucht%2C+A">Arne Laucht</a>, <a href="/search/quant-ph?searchtype=author&query=Dzurak%2C+A+S">Andrew S. Dzurak</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+C+H">Chih Hwan Yang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2311.09567v2-abstract-short" style="display: inline;"> Coherently dressed spins have shown promising results as building blocks for future quantum computers owing to their resilience to environmental noise and their compatibility with global control fields. This mode of operation allows for more amenable qubit architecture requirements and simplifies signal routing on the chip. However, multi-qubit operations, such as qubit addressability and two-qubi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.09567v2-abstract-full').style.display = 'inline'; document.getElementById('2311.09567v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2311.09567v2-abstract-full" style="display: none;"> Coherently dressed spins have shown promising results as building blocks for future quantum computers owing to their resilience to environmental noise and their compatibility with global control fields. This mode of operation allows for more amenable qubit architecture requirements and simplifies signal routing on the chip. However, multi-qubit operations, such as qubit addressability and two-qubit gates, are yet to be demonstrated to establish global control in combination with dressed qubits as a viable path to universal quantum computing. Here we demonstrate simultaneous on-resonance driving of degenerate qubits using a global field while retaining addressability for qubits with equal Larmor frequencies. Furthermore, we implement SWAP oscillations during on-resonance driving, constituting the demonstration of driven two-qubit gates. Significantly, our findings highlight the fragility of entangling gates between superposition states and how dressing can increase the noise robustness. These results represent a crucial milestone towards global control operation with dressed qubits. It also opens a door to interesting spin physics on degenerate spins. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.09567v2-abstract-full').style.display = 'none'; document.getElementById('2311.09567v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 November, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 16 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">Journal ref:</span> Nature Communications 15, 7656 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2310.18645">arXiv:2310.18645</a> <span> [<a href="https://arxiv.org/pdf/2310.18645">pdf</a>, <a href="https://arxiv.org/format/2310.18645">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevA.109.032415">10.1103/PhysRevA.109.032415 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Experimental verification of the steering ellipsoid zoo via two-qubit states </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Xu%2C+K">Kai Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+L">Lijun Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+N">Ning-Ning Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+C">Chao Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yun-Feng Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+B">Bi-Heng Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Cheng%2C+S">Shuming Cheng</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="2310.18645v2-abstract-short" style="display: inline;"> Quantum steering ellipsoid visualizes the set of all qubit states that can be steered by measuring on another correlated qubit in the Bloch picture. Together with local reduced states, it provides a faithful geometric characterization of the underlying two-qubit state so that almost all nonclassical state features can be reflected in its geometric properties. Consequently, the various types of qua… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.18645v2-abstract-full').style.display = 'inline'; document.getElementById('2310.18645v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2310.18645v2-abstract-full" style="display: none;"> Quantum steering ellipsoid visualizes the set of all qubit states that can be steered by measuring on another correlated qubit in the Bloch picture. Together with local reduced states, it provides a faithful geometric characterization of the underlying two-qubit state so that almost all nonclassical state features can be reflected in its geometric properties. Consequently, the various types of quantum ellipsoids with different geometric properties form an ellipsoid zoo, which, in this work, is experimentally verified via measurements on many polarization-path photonic states. By generating two-qubit states with high fidelity, the corresponding ellipsoids are constructed to certify the presence of entanglement, one-way Einstein-Podolsky-Rosen steering, discord, and steering incompleteness. It is also experimentally verified that the steering ellipsoid can be reconstructed from using the twelve vertices of the icosahedron as measurement directions. Our results aid progress in applying the quantum steering ellipsoid to reveal nonclassical features of the multi-qubit system. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.18645v2-abstract-full').style.display = 'none'; document.getElementById('2310.18645v2-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 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 28 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">Several references are added and the presentation is close to the publication version</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. A 109, 032415 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2310.12389">arXiv:2310.12389</a> <span> [<a href="https://arxiv.org/pdf/2310.12389">pdf</a>, <a href="https://arxiv.org/format/2310.12389">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Networking and Internet Architecture">cs.NI</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 Computing for MIMO Beam Selection Problem: Model and Optical Experimental Solution </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yuhong Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+W">Wenxin Li</a>, <a href="/search/quant-ph?searchtype=author&query=Pan%2C+C">Chengkang Pan</a>, <a href="/search/quant-ph?searchtype=author&query=Hou%2C+S">Shuai Hou</a>, <a href="/search/quant-ph?searchtype=author&query=Lu%2C+X">Xian Lu</a>, <a href="/search/quant-ph?searchtype=author&query=Cui%2C+C">Chunfeng Cui</a>, <a href="/search/quant-ph?searchtype=author&query=Wen%2C+J">Jingwei Wen</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+J">Jiaqi Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Cao%2C+C">Chongyu Cao</a>, <a href="/search/quant-ph?searchtype=author&query=Ma%2C+Y">Yin Ma</a>, <a href="/search/quant-ph?searchtype=author&query=Wei%2C+H">Hai Wei</a>, <a href="/search/quant-ph?searchtype=author&query=Wen%2C+K">Kai Wen</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="2310.12389v2-abstract-short" style="display: inline;"> Massive multiple-input multiple-output (MIMO) has gained widespread popularity in recent years due to its ability to increase data rates, improve signal quality, and provide better coverage in challenging environments. In this paper, we investigate the MIMO beam selection (MBS) problem, which is proven to be NP-hard and computationally intractable. To deal with this problem, quantum computing that… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.12389v2-abstract-full').style.display = 'inline'; document.getElementById('2310.12389v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2310.12389v2-abstract-full" style="display: none;"> Massive multiple-input multiple-output (MIMO) has gained widespread popularity in recent years due to its ability to increase data rates, improve signal quality, and provide better coverage in challenging environments. In this paper, we investigate the MIMO beam selection (MBS) problem, which is proven to be NP-hard and computationally intractable. To deal with this problem, quantum computing that can provide faster and more efficient solutions to large-scale combinatorial optimization is considered. MBS is formulated in a quadratic unbounded binary optimization form and solved with Coherent Ising Machine (CIM) physical machine. We compare the performance of our solution with two classic heuristics, simulated annealing and Tabu search. The results demonstrate an average performance improvement by a factor of 261.23 and 20.6, respectively, which shows that CIM-based solution performs significantly better in terms of selecting the optimal subset of beams. This work shows great promise for practical 5G operation and promotes the application of quantum computing in solving computationally hard problems in communication. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.12389v2-abstract-full').style.display = 'none'; document.getElementById('2310.12389v2-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 October, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 18 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">Accepted by IEEE Globecom 2023</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2310.08572">arXiv:2310.08572</a> <span> [<a href="https://arxiv.org/pdf/2310.08572">pdf</a>, <a href="https://arxiv.org/format/2310.08572">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Gases">cond-mat.quant-gas</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.110.205429">10.1103/PhysRevB.110.205429 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Non-Bloch band theory for non-Hermitian continuum systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Hu%2C+Y">Yu-Min Hu</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yin-Quan Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Xue%2C+W">Wen-Tan Xue</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zhong Wang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2310.08572v2-abstract-short" style="display: inline;"> One of the most pronounced non-Hermitian phenomena is the non-Hermitian skin effect, which refers to the exponential localization of bulk eigenstates near the boundaries of non-Hermitian systems. Whereas non-Bloch band theory has been developed to describe the non-Hermitian skin effect in lattice systems, its counterpart in continuum systems still lacks a quantitative characterization. Here, we ge… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.08572v2-abstract-full').style.display = 'inline'; document.getElementById('2310.08572v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2310.08572v2-abstract-full" style="display: none;"> One of the most pronounced non-Hermitian phenomena is the non-Hermitian skin effect, which refers to the exponential localization of bulk eigenstates near the boundaries of non-Hermitian systems. Whereas non-Bloch band theory has been developed to describe the non-Hermitian skin effect in lattice systems, its counterpart in continuum systems still lacks a quantitative characterization. Here, we generalize the non-Bloch band theory to non-Hermitian continuum systems. In contrast to lattice systems for which the bulk Hamiltonian alone determines the non-Hermitian skin effect and energy spectrum, we find for continuum systems that the number of boundary conditions, i.e., the number of independent differential equations satisfied by wavefunctions at two boundaries, must also be included as essential information. We show that the appropriate discretization of continuum systems into lattice models requires matching the hopping range of the latter with the number of boundary conditions in the former. Furthermore, in periodic non-Hermitian continuum systems, we highlight the application of the transfer matrix in determining the generalized Brillouin zone. Our theory serves as a useful toolbox for investigating the rich non-Bloch physics in non-Hermitian continuum systems, such as photonic crystals, elastic media, and certain cold-atom systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.08572v2-abstract-full').style.display = 'none'; document.getElementById('2310.08572v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 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">28 pages, 9 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, 205429 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2310.07120">arXiv:2310.07120</a> <span> [<a href="https://arxiv.org/pdf/2310.07120">pdf</a>, <a href="https://arxiv.org/format/2310.07120">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"> Dual epitaxial telecom spin-photon interfaces with correlated long-lived coherence </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Gupta%2C+S">Shobhit Gupta</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yizhong Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+S">Shihan Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Pei%2C+Y">Yuxiang Pei</a>, <a href="/search/quant-ph?searchtype=author&query=Tomm%2C+N">Natasha Tomm</a>, <a href="/search/quant-ph?searchtype=author&query=Warburton%2C+R+J">Richard J. Warburton</a>, <a href="/search/quant-ph?searchtype=author&query=Zhong%2C+T">Tian Zhong</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="2310.07120v1-abstract-short" style="display: inline;"> Optically active solid-state spin qubits thrive as an appealing technology for quantum interconnect and quantum networking, owing to their atomic size, scalable creation, long-lived coherence, and ability to coherently interface with flying qubits. Trivalent erbium dopants in particular emerge as a compelling candidate with their telecom C band emission and shielded 4f intra-shell spin-optical tra… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.07120v1-abstract-full').style.display = 'inline'; document.getElementById('2310.07120v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2310.07120v1-abstract-full" style="display: none;"> Optically active solid-state spin qubits thrive as an appealing technology for quantum interconnect and quantum networking, owing to their atomic size, scalable creation, long-lived coherence, and ability to coherently interface with flying qubits. Trivalent erbium dopants in particular emerge as a compelling candidate with their telecom C band emission and shielded 4f intra-shell spin-optical transitions. However, prevailing top-down architecture for rare-earth qubits and devices has not allowed simultaneous long optical and spin coherence necessary for long-distance quantum networks. Here we demonstrate dual erbium telecom spin-photon interfaces in an epitaxial thin-film platform via wafer-scale bottom-up synthesis. Harnessing precise controls over the matrix purity, dopant placement, and symmetry unique to this platform, we simultaneously achieve millisecond erbium spin coherence time and $<$3 kilohertz optical dephasing rate in an inversion-symmetry protected site and realize both optical and microwave control in a fiber-integrated package for rapid scaling up. These results demonstrate a significant prospect for high-quality rare-earth qubits and quantum memories assembled using a bottom-up method and pave the way for the large-scale development of quantum light-matter interfaces for telecommunication quantum networks. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.07120v1-abstract-full').style.display = 'none'; document.getElementById('2310.07120v1-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 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/2309.17304">arXiv:2309.17304</a> <span> [<a href="https://arxiv.org/pdf/2309.17304">pdf</a>, <a href="https://arxiv.org/format/2309.17304">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1002/qute.202300275">10.1002/qute.202300275 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Source-Replacement Model for Phase-Matching Quantum Key Distribution </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Y">Yizhi Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Du%2C+Z">Zhenyu Du</a>, <a href="/search/quant-ph?searchtype=author&query=Ma%2C+X">Xiongfeng 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="2309.17304v1-abstract-short" style="display: inline;"> Quantum key distribution has emerged as a promising solution for constructing secure communication networks, offering information-theoretic security guaranteed by the principles of quantum mechanics. One of the most advanced quantum key distribution protocols to date is the phase-matching protocol. Its security was initially established using an abstract method known as symmetry-protected privacy.… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.17304v1-abstract-full').style.display = 'inline'; document.getElementById('2309.17304v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2309.17304v1-abstract-full" style="display: none;"> Quantum key distribution has emerged as a promising solution for constructing secure communication networks, offering information-theoretic security guaranteed by the principles of quantum mechanics. One of the most advanced quantum key distribution protocols to date is the phase-matching protocol. Its security was initially established using an abstract method known as symmetry-protected privacy. In this study, we reevaluate the security of the phase-matching protocol using an intuitive source-replacement model, and we arrive at conclusions that align with the original proof. This model provides a fresh perspective on the protocol's security. As an application of this approach, we introduce a beam-splitting attack scheme. Leveraging the source-replacement model, we derive a lower bound on the phase error rate under this attack, further underscoring the robustness of our security analysis method. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.17304v1-abstract-full').style.display = 'none'; document.getElementById('2309.17304v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 29 September, 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">14 pages, 4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Adv Quantum Technol. 2024, 7, 2300275 </p> </li> </ol> <nav 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