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class="pagination-link " aria-label="Page 5" aria-current="page">5 </a> </li> <li> <a href="/search/?searchtype=author&query=Li%2C+S&start=250" class="pagination-link " aria-label="Page 6" aria-current="page">6 </a> </li> <li> <a href="/search/?searchtype=author&query=Li%2C+S&start=300" class="pagination-link " aria-label="Page 7" aria-current="page">7 </a> </li> </ul> </nav> <ol class="breathe-horizontal" start="1"> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.10750">arXiv:2411.10750</a> <span> [<a href="https://arxiv.org/pdf/2411.10750">pdf</a>, <a href="https://arxiv.org/format/2411.10750">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Other Condensed Matter">cond-mat.other</span> </div> </div> <p class="title is-5 mathjax"> Symmetry-protected Landau-Zener-St眉ckelberg-Majorana interference and non-adiabatic topological transport of edge states </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Hu%2C+S">Shi Hu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shihao Li</a>, <a href="/search/quant-ph?searchtype=author&query=Hu%2C+M">Meiqing Hu</a>, <a href="/search/quant-ph?searchtype=author&query=Lei%2C+Z">Zhoutao Lei</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="2411.10750v1-abstract-short" style="display: inline;"> We systematically investigate Landau-Zener-St眉ckelberg-Majorana (LZSM) interference under chiral-mirror-like symmetry and propose its application to non-adiabatic topological transport of edge states. Protected by this symmetry, complete destructive interference emerges and can be characterized through occupation probability. This symmetry-protected LZSM interference enables state transitions to b… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.10750v1-abstract-full').style.display = 'inline'; document.getElementById('2411.10750v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.10750v1-abstract-full" style="display: none;"> We systematically investigate Landau-Zener-St眉ckelberg-Majorana (LZSM) interference under chiral-mirror-like symmetry and propose its application to non-adiabatic topological transport of edge states. Protected by this symmetry, complete destructive interference emerges and can be characterized through occupation probability. This symmetry-protected LZSM interference enables state transitions to be achieved within remarkably short time scales. To demonstrate our mechanism, we provide two distinctive two-level systems as examples and survey them in detail. By tuning evolution speed or increasing holding time, the complete destructive interferences are observed. Furthermore, we make use of this mechanism for topological edge states of Su-Schrieffer-Heeger (SSH) chain by taking them as an isolated two-level system. Through carefully designed time sequences, we construct symmetry-protected LZSM interference of topological edge states, enabling non-adiabatic topological transport. Our work unveils an alternative way to study quantum control, quantum state transfer, and quantum communication via non-adiabatic topological transport. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.10750v1-abstract-full').style.display = 'none'; document.getElementById('2411.10750v1-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 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">10 pages, 3 figures; Comments are welcomed</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.02968">arXiv:2411.02968</a> <span> [<a href="https://arxiv.org/pdf/2411.02968">pdf</a>, <a href="https://arxiv.org/ps/2411.02968">ps</a>, <a href="https://arxiv.org/format/2411.02968">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"> Macroscopic quantum teleportation with ensembles of qubits </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chaudhary%2C+M">Manish Chaudhary</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+Z">Zhiyuan Lin</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shuang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+M">Mohan Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Mao%2C+Y">Yuping Mao</a>, <a href="/search/quant-ph?searchtype=author&query=Ivannikov%2C+V">Valentin Ivannikov</a>, <a href="/search/quant-ph?searchtype=author&query=Byrnes%2C+T">Tim Byrnes</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="2411.02968v1-abstract-short" style="display: inline;"> We develop methods for performing quantum teleportation of the total spin variables of an unknown state, using quantum nondemolition measurements, spin projection measurements, and classical communication. While theoretically teleportation of high-dimensional states can be attained with the assumption of generalized Bell measurements, this is typically experimentally non-trivial to implement. We i… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.02968v1-abstract-full').style.display = 'inline'; document.getElementById('2411.02968v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.02968v1-abstract-full" style="display: none;"> We develop methods for performing quantum teleportation of the total spin variables of an unknown state, using quantum nondemolition measurements, spin projection measurements, and classical communication. While theoretically teleportation of high-dimensional states can be attained with the assumption of generalized Bell measurements, this is typically experimentally non-trivial to implement. We introduce two protocols and show that, on average, the teleportation succeeds in teleporting the spin variables of a spin coherent state with average zero angular error in the ideal case, beating classical strategies based on quantum state estimation. In a single run of the teleportation, there is an angular error at the level of ~ 0.1 radians for large ensembles. A potential physical implementation for the scheme is with atomic ensembles and quantum nondemolition measurements performed with light. We analyze the decoherence of the protocols and find that the protocol is robust even in the limit of large ensemble sizes. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.02968v1-abstract-full').style.display = 'none'; document.getElementById('2411.02968v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">18 pages, 10 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.19275">arXiv:2410.19275</a> <span> [<a href="https://arxiv.org/pdf/2410.19275">pdf</a>, <a href="https://arxiv.org/ps/2410.19275">ps</a>, <a href="https://arxiv.org/format/2410.19275">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="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Finite Temperature Casimir Effect of Scalar Field: Revisit and New Results </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chen%2C+L">Liang Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Sheng-Yan Li</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2410.19275v2-abstract-short" style="display: inline;"> For both the one-dimensional and three-dimensional scalar fields at finite temperature, we find the analytic expressions of Gibbs free energy, Casimir force, and Casimir entropy. These results show that the widely used low-temperature approximation of thermal correction of Casimir force, $蟺{T}e^{-蟺{v}\hbar/aT}/2a^3$, have large errors with the exact solution. Here $T$, $v$ and $a$ represent the fi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.19275v2-abstract-full').style.display = 'inline'; document.getElementById('2410.19275v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.19275v2-abstract-full" style="display: none;"> For both the one-dimensional and three-dimensional scalar fields at finite temperature, we find the analytic expressions of Gibbs free energy, Casimir force, and Casimir entropy. These results show that the widely used low-temperature approximation of thermal correction of Casimir force, $蟺{T}e^{-蟺{v}\hbar/aT}/2a^3$, have large errors with the exact solution. Here $T$, $v$ and $a$ represent the finite temperature, the velocity of scalar field, and the distance between the two boundaries of the fields, respectively. $\hbar$ is the reduced Planck's constant. For three-dimensional scalar field, we find the leading order thermal correction of Gibbs free energy density, $F(a,T)=3味(7/2)aT^4/8蟺^{3/2}(v\hbar)^3$, where $味(.)$ represents the Riemann $味$ function. This thermal correction can not be cancelled by the blackbody radiation density, $蟺^2{a}T^4/90(v\hbar)^3$. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.19275v2-abstract-full').style.display = 'none'; document.getElementById('2410.19275v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 7 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 24 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 pages, 9 figures (Figures 5,8,9 are revised)</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.18892">arXiv:2410.18892</a> <span> [<a href="https://arxiv.org/pdf/2410.18892">pdf</a>, <a href="https://arxiv.org/format/2410.18892">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 observation of spin defects in van der Waals material GeS$_2$ </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Liu%2C+W">W. Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">S. Li</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+N+-">N. -J. Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Zeng%2C+X+-">X. -D. Zeng</a>, <a href="/search/quant-ph?searchtype=author&query=Xie%2C+L+-">L. -K. Xie</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+J+-">J. -Y. Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Ma%2C+Y+-">Y. -H. Ma</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y+-">Y. -Q. Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Y+-">Y. -T. Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z+-">Z. -A. Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Ren%2C+J+-">J. -M. Ren</a>, <a href="/search/quant-ph?searchtype=author&query=Ao%2C+C">C. Ao</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+J+-">J. -S. Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Tang%2C+J+-">J. -S. Tang</a>, <a href="/search/quant-ph?searchtype=author&query=Gali%2C+A">A. Gali</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+C+-">C. -F. Li</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+G+-">G. -C. Guo</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2410.18892v1-abstract-short" style="display: inline;"> Spin defects in atomically thin two-dimensional (2D) materials such as hexagonal boron nitride (hBN) attract significant attention for their potential quantum applications. The layered host materials not only facilitate seamless integration with optoelectronic devices but also enable the formation of heterostructures with on-demand functionality. Furthermore, their atomic thickness renders them pa… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.18892v1-abstract-full').style.display = 'inline'; document.getElementById('2410.18892v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.18892v1-abstract-full" style="display: none;"> Spin defects in atomically thin two-dimensional (2D) materials such as hexagonal boron nitride (hBN) attract significant attention for their potential quantum applications. The layered host materials not only facilitate seamless integration with optoelectronic devices but also enable the formation of heterostructures with on-demand functionality. Furthermore, their atomic thickness renders them particularly suitable for sensing applications. However, the short coherence times of the spin defects in hBN limit them in quantum applications that require extended coherence time. One primary reason is that both boron and nitrogen atoms have non-zero nuclear spins. Here, we present another 2D material germanium disulfide ($尾$-GeS$_2$) characterized by a wide bandgap and potential nuclear-spin-free lattice. This makes it as a promising host material for spin defects that possess long-coherence time. Our findings reveal the presence of more than two distinct types of spin defects in single-crystal $尾$-GeS$_2$. Coherent control of one type defect has been successfully demonstrated at both 5 K and room temperature, and the coherence time $T_2$ can achieve tens of microseconds, 100-folds of that of negatively charged boron vacancy (V$_{\text{B}}^-$) in hBN, satisfying the minimal threshold required for metropolitan quantum networks--one of the important applications of spins. We entatively assign the observed optical signals come from substitution defects. Together with previous theoretical prediction, we believe the coherence time can be further improved with optimized lattice quality, indicating $尾$-GeS$_2$ as a promising host material for long-coherence-time spins. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.18892v1-abstract-full').style.display = 'none'; document.getElementById('2410.18892v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 24 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 pages, 5 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.15389">arXiv:2410.15389</a> <span> [<a href="https://arxiv.org/pdf/2410.15389">pdf</a>, <a href="https://arxiv.org/format/2410.15389">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1126/sciadv.adr9527">10.1126/sciadv.adr9527 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Observation of quantum superposition of topological defects in a trapped ion quantum simulator </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Cheng%2C+Z">Zhijie Cheng</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yukai Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shijiao Li</a>, <a href="/search/quant-ph?searchtype=author&query=Mei%2C+Q">Quanxin Mei</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+B">Bowen Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+G">Gangxi Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Jiang%2C+Y">Yue Jiang</a>, <a href="/search/quant-ph?searchtype=author&query=Qi%2C+B">Binxiang Qi</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zichao Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Hou%2C+P">Panyu Hou</a>, <a href="/search/quant-ph?searchtype=author&query=Duan%2C+L">Luming Duan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2410.15389v1-abstract-short" style="display: inline;"> Topological defects are discontinuities of a system protected by global properties, with wide applications in mathematics and physics. While previous experimental studies mostly focused on their classical properties, it has been predicted that topological defects can exhibit quantum superposition. Despite the fundamental interest and potential applications in understanding symmetry-breaking dynami… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.15389v1-abstract-full').style.display = 'inline'; document.getElementById('2410.15389v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.15389v1-abstract-full" style="display: none;"> Topological defects are discontinuities of a system protected by global properties, with wide applications in mathematics and physics. While previous experimental studies mostly focused on their classical properties, it has been predicted that topological defects can exhibit quantum superposition. Despite the fundamental interest and potential applications in understanding symmetry-breaking dynamics of quantum phase transitions, its experimental realization still remains a challenge. Here, we report the observation of quantum superposition of topological defects in a trapped-ion quantum simulator. By engineering long-range spin-spin interactions, we observe a spin kink splitting into a superposition of kinks at different positions, creating a ``Schrodinger kink'' that manifests non-locality and quantum interference. Furthermore, by preparing superposition states of neighboring kinks with different phases, we observe the propagation of the wave packet in different directions, thus unambiguously verifying the quantum coherence in the superposition states. Our work provides useful tools for non-equilibrium dynamics in quantum Kibble-Zurek physics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.15389v1-abstract-full').style.display = 'none'; document.getElementById('2410.15389v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 20 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 pages, 6 figures, already published in Science Advances</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Sci. Adv.10,eadr9527(2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.11609">arXiv:2410.11609</a> <span> [<a href="https://arxiv.org/pdf/2410.11609">pdf</a>, <a href="https://arxiv.org/ps/2410.11609">ps</a>, <a href="https://arxiv.org/format/2410.11609">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Wigner-Yanase skew information, quantum entanglement and spin nematic quantum phase transitions in biquadratic spin-1 and spin-2 XY chains with single-ion anisotropies </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Dai%2C+Y">Yan-Wei Dai</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Sheng-Hao Li</a>, <a href="/search/quant-ph?searchtype=author&query=Cho%2C+S+Y">Sam Young Cho</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+H">Huan-Qiang 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="2410.11609v1-abstract-short" style="display: inline;"> Quantum phase transitions (QPTs) between uniaxial or biaxial spin nematic (SN) phases are investigated in biquadratic spin-1 and spin-2 XY infinite chains with the rhombic- and uniaxial-type single-ion anisotropies. Systematic discussions of distinctive singular behaviors are made to classify various types of QPT from one SN state to the other SN state in using the Wigner-Yanase skew information (… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.11609v1-abstract-full').style.display = 'inline'; document.getElementById('2410.11609v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.11609v1-abstract-full" style="display: none;"> Quantum phase transitions (QPTs) between uniaxial or biaxial spin nematic (SN) phases are investigated in biquadratic spin-1 and spin-2 XY infinite chains with the rhombic- and uniaxial-type single-ion anisotropies. Systematic discussions of distinctive singular behaviors are made to classify various types of QPT from one SN state to the other SN state in using the Wigner-Yanase skew information (WYSI), the bipartite entanglement entropy (BEE), and the quadrupole moments (QMs). For the spin-1 system with the three uniaxial SN phases, we find that a discontinuous QPT, signaled by discontinuous behaviors of all the considered WYSI, BEE, and QMs, occurs from the z-ferroquadrupole phase (FQP) to the x- or y-FQPs, while a continuous QPT occurs between the x- and y-FQPs. The central charge in the continuous QPT line is estimated as $c \simeq 1$ from the BEE. Compared to the spin-1 system, depending on a given strength of the uniaxial-type single-ion anisotropy, the spin-2 system undergoes four different types of QPTs between the two biaxial SN phases as the rhombic-type anisotropy varies: the quantum crossovers, connecting the two orthogonal biaxial SN states adiabatically without an explicit phase transition, the continuous and the discontinuous QPTs, and the SN to magnetic transitions via the antiferromagnetic phase (AFP). In a sharp contrast to the spin-1 system, for the transitions between the two biaxial SN phases, the discontinuous transition line is classified as a topological phase characterized by a doubly degenerate entanglement spectrum and a string order parameter defined by the Cartan generator of the $\mathrm{SO}(5)$ symmetry group in spin-2 systems, while the continuous QPT is advocated by the central charge $c \simeq 1$. Whereas the QPT lines with $c \simeq 1/2$ indicate that the transition between the biaxial SN phase and the AFP belongs to the Ising universality class. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.11609v1-abstract-full').style.display = 'none'; document.getElementById('2410.11609v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">23 pages, 26 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.04469">arXiv:2410.04469</a> <span> [<a href="https://arxiv.org/pdf/2410.04469">pdf</a>, <a href="https://arxiv.org/format/2410.04469">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Disordered Systems and Neural Networks">cond-mat.dis-nn</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Emergent Matryoshka doll-like point gap in a non-Hermitian quasiperiodic lattice </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zheng%2C+Y">Yi-Qi Zheng</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shan-Zhong Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zhi Li</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2410.04469v1-abstract-short" style="display: inline;"> We propose a geometric series modulated non-Hermitian quasiperiodic lattice model, and explore its localization and topological properties. The results show that with the ever-increasing summation terms of the geometric series, multiple mobility edges and non-Hermitian point gaps with high winding number can be induced in the system. The point gap spectrum of the system has a Matryoshka doll-like… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.04469v1-abstract-full').style.display = 'inline'; document.getElementById('2410.04469v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.04469v1-abstract-full" style="display: none;"> We propose a geometric series modulated non-Hermitian quasiperiodic lattice model, and explore its localization and topological properties. The results show that with the ever-increasing summation terms of the geometric series, multiple mobility edges and non-Hermitian point gaps with high winding number can be induced in the system. The point gap spectrum of the system has a Matryoshka doll-like structure in the complex plane, resulting in a high winding number. In addition, we analyze the limit case of summation of infinite terms. The results show that the mobility edges merge together as only one mobility edge when summation terms are pushed to the limit. Meanwhile, the corresponding point gaps are merged into a ring with winding number equal to one. Through Avila's global theory, we give an analytical expression for mobility edges in the limit of infinite summation, reconfirming that mobility edges and point gaps do merge and will result in a winding number that is indeed equal to one. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.04469v1-abstract-full').style.display = 'none'; document.getElementById('2410.04469v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 6 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">main 6 pages, 7 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2409.10055">arXiv:2409.10055</a> <span> [<a href="https://arxiv.org/pdf/2409.10055">pdf</a>, <a href="https://arxiv.org/format/2409.10055">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"> On the Trainability and Classical Simulability of Learning Matrix Product States Variationally </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Basheer%2C+A">Afrad Basheer</a>, <a href="/search/quant-ph?searchtype=author&query=Feng%2C+Y">Yuan Feng</a>, <a href="/search/quant-ph?searchtype=author&query=Ferrie%2C+C">Christopher Ferrie</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Sanjiang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Pashayan%2C+H">Hakop Pashayan</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="2409.10055v1-abstract-short" style="display: inline;"> We prove that using global observables to train the matrix product state ansatz results in the vanishing of all partial derivatives, also known as barren plateaus, while using local observables avoids this. This ansatz is widely used in quantum machine learning for learning weakly entangled state approximations. Additionally, we empirically demonstrate that in many cases, the objective function is… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.10055v1-abstract-full').style.display = 'inline'; document.getElementById('2409.10055v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.10055v1-abstract-full" style="display: none;"> We prove that using global observables to train the matrix product state ansatz results in the vanishing of all partial derivatives, also known as barren plateaus, while using local observables avoids this. This ansatz is widely used in quantum machine learning for learning weakly entangled state approximations. Additionally, we empirically demonstrate that in many cases, the objective function is an inner product of almost sparse operators, highlighting the potential for classically simulating such a learning problem with few quantum resources. All our results are experimentally validated across various scenarios. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.10055v1-abstract-full').style.display = 'none'; document.getElementById('2409.10055v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 September, 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">17 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/2409.08982">arXiv:2409.08982</a> <span> [<a href="https://arxiv.org/pdf/2409.08982">pdf</a>, <a href="https://arxiv.org/format/2409.08982">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> A Fiber-pigtailed Quantum Dot Device Generating Indistinguishable Photons at GHz Clock-rates </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Rickert%2C+L">Lucas Rickert</a>, <a href="/search/quant-ph?searchtype=author&query=%C5%BBo%C5%82nacz%2C+K">Kinga 呕o艂nacz</a>, <a href="/search/quant-ph?searchtype=author&query=Vajner%2C+D+A">Daniel A. Vajner</a>, <a href="/search/quant-ph?searchtype=author&query=von+Helversen%2C+M">Martin von Helversen</a>, <a href="/search/quant-ph?searchtype=author&query=Rodt%2C+S">Sven Rodt</a>, <a href="/search/quant-ph?searchtype=author&query=Reitzenstein%2C+S">Stephan Reitzenstein</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+H">Hanqing Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shulun Li</a>, <a href="/search/quant-ph?searchtype=author&query=Ni%2C+H">Haiqiao Ni</a>, <a href="/search/quant-ph?searchtype=author&query=Wyborski%2C+P">Pawe艂 Wyborski</a>, <a href="/search/quant-ph?searchtype=author&query=S%C4%99k%2C+G">Grzegorz S臋k</a>, <a href="/search/quant-ph?searchtype=author&query=Musia%C5%82%2C+A">Anna Musia艂</a>, <a href="/search/quant-ph?searchtype=author&query=Niu%2C+Z">Zhichuan Niu</a>, <a href="/search/quant-ph?searchtype=author&query=Heindel%2C+T">Tobias Heindel</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="2409.08982v1-abstract-short" style="display: inline;"> Solid-state quantum light sources based on semiconductor quantum dots (QDs) are increasingly employed in photonic quantum information applications. Especially when moving towards real-world scenarios outside shielded lab environments, the efficient and robust coupling of nanophotonic devices to single-mode optical fibers offers substantial advantage by enabling "plug-and-play" operation. In this w… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.08982v1-abstract-full').style.display = 'inline'; document.getElementById('2409.08982v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.08982v1-abstract-full" style="display: none;"> Solid-state quantum light sources based on semiconductor quantum dots (QDs) are increasingly employed in photonic quantum information applications. Especially when moving towards real-world scenarios outside shielded lab environments, the efficient and robust coupling of nanophotonic devices to single-mode optical fibers offers substantial advantage by enabling "plug-and-play" operation. In this work we present a fiber-pigtailed cavity-enhanced source of flying qubits emitting single indistinguishable photons at clock-rates exceeding 1 GHz. This is achieved by employing a fully deterministic technique for fiber-pigtailing optimized QD-devices based on hybrid circular Bragg grating (hCBG) micro-cavities. The fabricated fiber-pigtailed hCBGs feature radiative emission lifetimes of $<$80 ps, corresponding to a Purcell factor of $\sim$9, a suppression of multiphoton emission events with $g^{(2)}$(0) $<$1%, a photon-indistinguishability >80% and a measured single-photon coupling efficiency of 53% in a high numerical aperture single-mode fiber, corresponding to 1.2 Megaclicks per second at the single-photon detectors. Our results show that fiber-pigtailed quantum light sources based on hCBG cavities are a prime candidate for applications of quantum information science. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.08982v1-abstract-full').style.display = 'none'; document.getElementById('2409.08982v1-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 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, 5 figures. The current v1 version of the manuscript referes to a Supplementary Information (S.I.) for further experimental details. This S.I. will be provided attached to a v2-Version of the manuscript that incoorperates potential revisions for a related journal submission</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2409.04752">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/2409.03185">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/2409.02767">arXiv:2409.02767</a> <span> [<a href="https://arxiv.org/pdf/2409.02767">pdf</a>, <a href="https://arxiv.org/format/2409.02767">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevA.110.032438">10.1103/PhysRevA.110.032438 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Hong-Ou-Mandel Interference in a temporal-average-inversion-symmetric chain </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Hu%2C+S">Shi Hu</a>, <a href="/search/quant-ph?searchtype=author&query=Hu%2C+M">Meiqing Hu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shihao Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhong%2C+Z">Zihui Zhong</a>, <a href="/search/quant-ph?searchtype=author&query=Lei%2C+Z">Zhoutao Lei</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="2409.02767v1-abstract-short" style="display: inline;"> We show how to implement tunable beam splitter and Hong-Ou-Mandel interference in the Su-Schrieffer-Heeger chain by manipulating the topological edge states adiabatically. The boson initially injected in the one end of the chain can be transferred to the two-end with a tunable proportion depends on the dynamical phases accumulated during the adiabatic evolution. We also observe Hong-Ou-Mandel inte… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.02767v1-abstract-full').style.display = 'inline'; document.getElementById('2409.02767v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.02767v1-abstract-full" style="display: none;"> We show how to implement tunable beam splitter and Hong-Ou-Mandel interference in the Su-Schrieffer-Heeger chain by manipulating the topological edge states adiabatically. The boson initially injected in the one end of the chain can be transferred to the two-end with a tunable proportion depends on the dynamical phases accumulated during the adiabatic evolution. We also observe Hong-Ou-Mandel interference via the tunable beam splitter ($50:50$) and achieve a spatially entangled two-particle NOON state. We demonstrate the robustness of our proposal under chiral- and time-reversal-symmetry-preserving disorder. However, the chiral symmetry is scarce for realist system. Therefore, we demonstrate Hong-Ou-Mandel interference are robust to inversion symmetric disorder breaking the chiral symmetry, highlighting the protection of inversion symmetry. More importantly, the inversion symmetry violated by static disorder can be restored for more common situations where disorder becomes time dependent, giving rise to the temporal-average-inversion-symmetry protected Hong-Ou-Mandel interference. Our approach opens a new way to study quantum effects in topological matter with potential applications. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.02767v1-abstract-full').style.display = 'none'; document.getElementById('2409.02767v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> PhysRevA.110, 032438 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.16617">arXiv:2408.16617</a> <span> [<a href="https://arxiv.org/pdf/2408.16617">pdf</a>, <a href="https://arxiv.org/format/2408.16617">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"> Long-Range $ZZ$ Interaction via Resonator-Induced Phase in Superconducting Qubits </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Deng%2C+X">Xiang Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Zheng%2C+W">Wen Zheng</a>, <a href="/search/quant-ph?searchtype=author&query=Liao%2C+X">Xudong Liao</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+H">Haoyu Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Ge%2C+Y">Yangyang Ge</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+J">Jie Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Lan%2C+D">Dong Lan</a>, <a href="/search/quant-ph?searchtype=author&query=Tan%2C+X">Xinsheng Tan</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Y">Yu Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shaoxiong Li</a>, <a href="/search/quant-ph?searchtype=author&query=Yu%2C+Y">Yang Yu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2408.16617v2-abstract-short" style="display: inline;"> Superconducting quantum computing emerges as one of leading candidates for achieving quantum advantage. However, a prevailing challenge is the coding overhead due to limited quantum connectivity, constrained by nearest-neighbor coupling among superconducting qubits. Here, we propose a novel multimode coupling scheme using three resonators driven by two microwaves, based on the resonator-induced ph… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.16617v2-abstract-full').style.display = 'inline'; document.getElementById('2408.16617v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.16617v2-abstract-full" style="display: none;"> Superconducting quantum computing emerges as one of leading candidates for achieving quantum advantage. However, a prevailing challenge is the coding overhead due to limited quantum connectivity, constrained by nearest-neighbor coupling among superconducting qubits. Here, we propose a novel multimode coupling scheme using three resonators driven by two microwaves, based on the resonator-induced phase gate, to extend the $ZZ$ interaction distance between qubits. We demonstrate a CZ gate fidelity exceeding 99.9\% within 160 ns at free spectral range (FSR) of 1.4 GHz, and by optimizing driving pulses, we further reduce the residual photon to nearly $10^{-3}$ within 100 ns at FSR of 0.2 GHz. These facilitate the long-range CZ gate over separations reaching sub-meters, thus significantly enhancing qubit connectivity and making a practical step towards the scalable integration and modularization of quantum processors. Specifically, our approach supports the implementation of quantum error correction codes requiring high connectivity, such as low-density parity check codes that paves the way to achieving fault-tolerant quantum computing. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.16617v2-abstract-full').style.display = 'none'; document.getElementById('2408.16617v2-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">v1</span> submitted 29 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">7 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/2408.13515">arXiv:2408.13515</a> <span> [<a href="https://arxiv.org/pdf/2408.13515">pdf</a>, <a href="https://arxiv.org/format/2408.13515">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Quantum Emission from Coupled Spin Pairs in Hexagonal Boron Nitride </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Song Li</a>, <a href="/search/quant-ph?searchtype=author&query=Pershin%2C+A">Anton Pershin</a>, <a href="/search/quant-ph?searchtype=author&query=Gali%2C+A">Adam Gali</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="2408.13515v2-abstract-short" style="display: inline;"> Optically addressable defect qubits in wide band gap materials are favorable candidates for room temperature quantum information processing. The two-dimensional (2D) hexagonal boron nitride (hBN) is an attractive solid state platform with a great potential for hosting bright quantum emitters with quantum memories with leveraging the potential of 2D materials for realizing scalable preparation of d… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.13515v2-abstract-full').style.display = 'inline'; document.getElementById('2408.13515v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.13515v2-abstract-full" style="display: none;"> Optically addressable defect qubits in wide band gap materials are favorable candidates for room temperature quantum information processing. The two-dimensional (2D) hexagonal boron nitride (hBN) is an attractive solid state platform with a great potential for hosting bright quantum emitters with quantum memories with leveraging the potential of 2D materials for realizing scalable preparation of defect qubits. Although, room temperature bright defect qubits have been recently reported in hBN but their microscopic origin, the nature of the optical transition as well as the optically detected magnetic resonance (ODMR) have been remained elusive. Here we connect the variance in the optical spectra, optical lifetimes and spectral stability of quantum emitters to donor-acceptor pairs (DAP) in hBN by means of ab initio calculations. We find that DAPs can exhibit ODMR signal for the acceptor counterpart of the defect pair with S=1/2 ground state at non-zero magnetic fields depending on the donor partner. The donor-acceptor pair model and its transition mechanisms provide a recipe towards defect qubit identification and performance optimization in hBN for quantum applications. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.13515v2-abstract-full').style.display = 'none'; document.getElementById('2408.13515v2-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 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 24 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.12075">arXiv:2408.12075</a> <span> [<a href="https://arxiv.org/pdf/2408.12075">pdf</a>, <a href="https://arxiv.org/format/2408.12075">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Atomic Physics">physics.atom-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.133.113204">10.1103/PhysRevLett.133.113204 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Electromagnetically-Induced-Transparency Cooling of High-Nuclear-Spin Ions </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Huang%2C+C">Chuanxin Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+C">Chenxi Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+H">Hongxuan Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Hu%2C+H">Hongyuan Hu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zuqing Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Mao%2C+Z">Zhichao Mao</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shijiao Li</a>, <a href="/search/quant-ph?searchtype=author&query=Hou%2C+P">Panyu Hou</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yukai Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+Z">Zichao Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Duan%2C+L">Luming Duan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2408.12075v1-abstract-short" style="display: inline;"> We report the electromagnetically-induced-transparency (EIT) cooling of $^{137}\mathrm{Ba}^{+}$ ions with a nuclear spin of $I=3/2$, which are a good candidate of qubits for future large-scale trapped ion quantum computing. EIT cooling of atoms or ions with a complex ground-state level structure is challenging due to the lack of an isolated $螞$ system, as the population can escape from the $螞$ sys… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.12075v1-abstract-full').style.display = 'inline'; document.getElementById('2408.12075v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.12075v1-abstract-full" style="display: none;"> We report the electromagnetically-induced-transparency (EIT) cooling of $^{137}\mathrm{Ba}^{+}$ ions with a nuclear spin of $I=3/2$, which are a good candidate of qubits for future large-scale trapped ion quantum computing. EIT cooling of atoms or ions with a complex ground-state level structure is challenging due to the lack of an isolated $螞$ system, as the population can escape from the $螞$ system to reduce the cooling efficiency. We overcome this issue by leveraging an EIT pumping laser to repopulate the cooling subspace, ensuring continuous and effective EIT cooling. We cool the two radial modes of a single $^{137}\mathrm{Ba}^{+}$ ion to average motional occupations of 0.08(5) and 0.15(7) respectively. Using the same laser parameters, we also cool all the ten radial modes of a five-ion chain to near their ground states. Our approach can be adapted to atomic species possessing similar level structures. It allows engineering of the EIT Fano-like spectrum, which can be useful for simultaneous cooling of modes across a wide frequency range, aiding in large-scale trapped-ion quantum information processing. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.12075v1-abstract-full').style.display = 'none'; document.getElementById('2408.12075v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> PhysRevLett.133.113204 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.09965">arXiv:2408.09965</a> <span> [<a href="https://arxiv.org/pdf/2408.09965">pdf</a>, <a href="https://arxiv.org/ps/2408.09965">ps</a>, <a href="https://arxiv.org/format/2408.09965">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Statistical Mechanics">cond-mat.stat-mech</span> </div> </div> <p class="title is-5 mathjax"> Relaxing towards generalized one-body Boltzmann states </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Sheng-Wen Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+N">Ning Wu</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="2408.09965v1-abstract-short" style="display: inline;"> Isolated quantum systems follow the reversible unitary evolution; if we focus on the dynamics of local states and observables, they exhibit the irreversible relaxation behaviors. Here we study the local relaxation process in an isolated chain consisting of \emph{N} three level systems. Though the entropy of the full many body state keeps a constant, it turns out the total correlation of this syste… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.09965v1-abstract-full').style.display = 'inline'; document.getElementById('2408.09965v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.09965v1-abstract-full" style="display: none;"> Isolated quantum systems follow the reversible unitary evolution; if we focus on the dynamics of local states and observables, they exhibit the irreversible relaxation behaviors. Here we study the local relaxation process in an isolated chain consisting of \emph{N} three level systems. Though the entropy of the full many body state keeps a constant, it turns out the total correlation of this system approximately exhibits a monotonically increasing behavior. More importantly, a variation analysis shows that, the total correlation entropy would achieve its theoretical maximum when each site stays in a generalized one-body Boltzmann state, which is not solely determined by the energy but also depends on the spin value of each onsite level. It turns out such a theoretical correlation maximum is highly coincident with the result obtained from the exact time dependent evolution. In this sense, the total correlation entropy well serves as an indicator for the dynamical irreversibility of the nonequilibrium relaxation in this isolated system. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.09965v1-abstract-full').style.display = 'none'; document.getElementById('2408.09965v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 19 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">7 pages, 4 figures, comments are welcome</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.08429">arXiv:2408.08429</a> <span> [<a href="https://arxiv.org/pdf/2408.08429">pdf</a>, <a href="https://arxiv.org/ps/2408.08429">ps</a>, <a href="https://arxiv.org/format/2408.08429">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Theory">hep-th</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mathematical Physics">math-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> SLOCC and LU classification of black holes with eight electric and magnetic charges </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+D">Dafa Li</a>, <a href="/search/quant-ph?searchtype=author&query=Cheng%2C+M">Maggie Cheng</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xiangrong Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shuwang Li</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2408.08429v1-abstract-short" style="display: inline;"> In \cite{Linde}, Kallosh and Linde discussed the SLOCC classification of black holes. However, the criteria for the SLOCC classification of black holes have not been given. In addition, the LU classification of black holes has not been studied in the past. In this paper we will consider both SLOCC and LU classification of the STU black holes with four integer electric charges $q_{i} $ and four int… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.08429v1-abstract-full').style.display = 'inline'; document.getElementById('2408.08429v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.08429v1-abstract-full" style="display: none;"> In \cite{Linde}, Kallosh and Linde discussed the SLOCC classification of black holes. However, the criteria for the SLOCC classification of black holes have not been given. In addition, the LU classification of black holes has not been studied in the past. In this paper we will consider both SLOCC and LU classification of the STU black holes with four integer electric charges $q_{i} $ and four integer magnetic charges $p^{i}$, $i=0,1,2,3$. Two STU black holes with eight charges are considered SLOCC (LU) equivalent if and only if their corresponding states of three qubits are SLOCC (LU) equivalent. Under this definition, we give criteria for the classification of the eight-charge STU black holes under SLOCC and under LU, respectively. We will study the classification of the black holes via the classification of SLOCC and LU entanglement of three qubits. We then identify a set of black holes corresponding to the state W of three qubits, which is of interest since it has the maximal average von Neumann entropy of entanglement. Via von Neumann entanglement entropy, we partition the STU black holes corresponding to pure states of GHZ SLOCC class into five families under LU. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.08429v1-abstract-full').style.display = 'none'; document.getElementById('2408.08429v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Int J theor phys 63, issue 6, 144 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.02543">arXiv:2408.02543</a> <span> [<a href="https://arxiv.org/pdf/2408.02543">pdf</a>, <a href="https://arxiv.org/format/2408.02543">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"> High Purcell-enhancement in quantum-dot hybrid circular Bragg grating cavities for GHz-clockrate generation of indistinguishable photons </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Rickert%2C+L">Lucas Rickert</a>, <a href="/search/quant-ph?searchtype=author&query=Vajner%2C+D+A">Daniel A. Vajner</a>, <a href="/search/quant-ph?searchtype=author&query=von+Helversen%2C+M">Martin von Helversen</a>, <a href="/search/quant-ph?searchtype=author&query=Schall%2C+J">Johannes Schall</a>, <a href="/search/quant-ph?searchtype=author&query=Rodt%2C+S">Sven Rodt</a>, <a href="/search/quant-ph?searchtype=author&query=Reitzenstein%2C+S">Stephan Reitzenstein</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+H">Hanqing Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shulun Li</a>, <a href="/search/quant-ph?searchtype=author&query=Ni%2C+H">Haiqiao Ni</a>, <a href="/search/quant-ph?searchtype=author&query=Niu%2C+Z">Zhichuan Niu</a>, <a href="/search/quant-ph?searchtype=author&query=Heindel%2C+T">Tobias Heindel</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="2408.02543v1-abstract-short" style="display: inline;"> We present Purcell-enhanced ($F_\mathrm{P} > 25$) semiconductor InAs quantum dot radiative lifetimes of $T_1 < 30~\mathrm{ps}$, enabled by deterministic hybrid circular Bragg gratings (hCBGs). We investigate the benefits of these short T1 times on the two-photon indistinguishability for quasi-resonant and strictly resonant excitation, and observe visibilities $\geq96\%$ at 12.5 ns time delay of co… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.02543v1-abstract-full').style.display = 'inline'; document.getElementById('2408.02543v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.02543v1-abstract-full" style="display: none;"> We present Purcell-enhanced ($F_\mathrm{P} > 25$) semiconductor InAs quantum dot radiative lifetimes of $T_1 < 30~\mathrm{ps}$, enabled by deterministic hybrid circular Bragg gratings (hCBGs). We investigate the benefits of these short T1 times on the two-photon indistinguishability for quasi-resonant and strictly resonant excitation, and observe visibilities $\geq96\%$ at 12.5 ns time delay of consecutively emitted photons. The strongly Purcell-enhanced decay times enable a high degree of indistinguishability for elevated temperatures of up to 30 K, and moreover, allow for excitation of up to 1.28 GHz repetition rate. Our work highlights the prospects of high Purcell enhanced solid-state quantum emitters for applications in quantum information and technologies operating at GHz clock-rates. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.02543v1-abstract-full').style.display = 'none'; document.getElementById('2408.02543v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 August, 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">14 pages, 5 figures. The current manuscript v1 references a Supplementary Information for further experimental details. This S.I. will be added in a v2-version of the manuscript, once the peer-review of the related journal submission is complete</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.21466">arXiv:2407.21466</a> <span> [<a href="https://arxiv.org/pdf/2407.21466">pdf</a>, <a href="https://arxiv.org/format/2407.21466">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Gases">cond-mat.quant-gas</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Pattern Formation and Solitons">nlin.PS</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"> Nonlinearity-induced dynamical self-organized twisted-bilayer lattices in Bose-Einstein condensates </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Tian%2C+R">Rui Tian</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Y">Yue Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+T">Tianhao Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+M">Min Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Y">Yong-Chang Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shuai Li</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+B">Bo Liu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2407.21466v1-abstract-short" style="display: inline;"> Creating crystal bilayers twisted with respect to each other would lead to large periodic supercell structures, which can support a wide range of novel electron correlated phenomena, where the full understanding is still under debate. Here, we propose a new scheme to realize a nonlinearity-induced dynamical self-organized twisted-bilayer lattice in an atomic Bose-Einstein condensate (BEC). The key… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.21466v1-abstract-full').style.display = 'inline'; document.getElementById('2407.21466v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.21466v1-abstract-full" style="display: none;"> Creating crystal bilayers twisted with respect to each other would lead to large periodic supercell structures, which can support a wide range of novel electron correlated phenomena, where the full understanding is still under debate. Here, we propose a new scheme to realize a nonlinearity-induced dynamical self-organized twisted-bilayer lattice in an atomic Bose-Einstein condensate (BEC). The key idea here is to utilize the nonlinear effect from the intrinsic atomic interactions to couple different layers and induce a dynamical self-organized supercell structure, dramatically distinct from the conventional wisdom to achieve the static twisted-bilayer lattices. To illustrate that, we study the dynamics of a two-component BEC and show that the nonlinear interaction effect naturally emerged in the Gross-Pitaevskii equation of interacting bosonic ultracold atoms can dynamically induce both periodic (commensurable) and aperiodic (incommensurable) moir茅 structures. One of the interesting moir茅 phenomena, i.e., the flat-band physics, is shown through investigating the dynamics of the wave packet of BEC. Our proposal can be implemented using available state-of-the-art experimental techniques and reveal a profound connection between the nonlinearity and twistronics in cold atom quantum simulators. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.21466v1-abstract-full').style.display = 'none'; document.getElementById('2407.21466v1-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 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">6 pages, 5 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.21415">arXiv:2407.21415</a> <span> [<a href="https://arxiv.org/pdf/2407.21415">pdf</a>, <a href="https://arxiv.org/format/2407.21415">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"> In situ Qubit Frequency Tuning Circuit for Scalable Superconducting Quantum Computing: Scheme and Experiment </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Jiang%2C+L">Lei Jiang</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+Y">Yu Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shaowei Li</a>, <a href="/search/quant-ph?searchtype=author&query=Yan%2C+Z">Zhiguang Yan</a>, <a href="/search/quant-ph?searchtype=author&query=Gong%2C+M">Ming Gong</a>, <a href="/search/quant-ph?searchtype=author&query=Rong%2C+T">Tao Rong</a>, <a href="/search/quant-ph?searchtype=author&query=Sun%2C+C">Chenyin Sun</a>, <a href="/search/quant-ph?searchtype=author&query=Sun%2C+T">Tianzuo Sun</a>, <a href="/search/quant-ph?searchtype=author&query=Jiang%2C+T">Tao Jiang</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+H">Hui Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Zha%2C+C">Chen Zha</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+J">Jin Lin</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+F">Fusheng Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+Q">Qingling Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Ye%2C+Y">Yangsen Ye</a>, <a href="/search/quant-ph?searchtype=author&query=Rong%2C+H">Hao Rong</a>, <a href="/search/quant-ph?searchtype=author&query=Yan%2C+K">Kai Yan</a>, <a href="/search/quant-ph?searchtype=author&query=Cao%2C+S">Sirui Cao</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yuan Li</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+S">Shaojun Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Qian%2C+H">Haoran Qian</a>, <a href="/search/quant-ph?searchtype=author&query=Hu%2C+Y">Yisen Hu</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+Y">Yulin Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yuhuai Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+G">Gang Wu</a> , et al. (8 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="2407.21415v1-abstract-short" style="display: inline;"> Frequency tunable qubit plays a significant role for scalable superconducting quantum processors. The state-of-the-art room-temperature electronics for tuning qubit frequency suffers from unscalable limit, such as heating problem, linear growth of control cables, etc. Here we propose a scalable scheme to tune the qubit frequency by using in situ superconducting circuit, which is based on radio fre… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.21415v1-abstract-full').style.display = 'inline'; document.getElementById('2407.21415v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.21415v1-abstract-full" style="display: none;"> Frequency tunable qubit plays a significant role for scalable superconducting quantum processors. The state-of-the-art room-temperature electronics for tuning qubit frequency suffers from unscalable limit, such as heating problem, linear growth of control cables, etc. Here we propose a scalable scheme to tune the qubit frequency by using in situ superconducting circuit, which is based on radio frequency superconducting quantum interference device (rf-SQUID). We demonstrate both theoretically and experimentally that the qubit frequency could be modulated by inputting several single pulses into rf-SQUID. Compared with the traditional scheme, our scheme not only solves the heating problem, but also provides the potential to exponentially reduce the number of cables inside the dilute refrigerator and the room-temperature electronics resource for tuning qubit frequency, which is achieved by a time-division-multiplex (TDM) scheme combining rf-SQUID with switch arrays. With such TDM scheme, the number of cables could be reduced from the usual $\sim 3n$ to $\sim \log_2{(3n)} + 1$ for two-dimensional quantum processors comprising $n$ qubits and $\sim 2n$ couplers. Our work paves the way for large-scale control of superconducting quantum processor. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.21415v1-abstract-full').style.display = 'none'; document.getElementById('2407.21415v1-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 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">9 pages, 6 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.20134">arXiv:2407.20134</a> <span> [<a href="https://arxiv.org/pdf/2407.20134">pdf</a>, <a href="https://arxiv.org/format/2407.20134">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"> Modular quantum processor with an all-to-all reconfigurable router </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wu%2C+X">Xuntao Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Yan%2C+H">Haoxiong Yan</a>, <a href="/search/quant-ph?searchtype=author&query=Andersson%2C+G">Gustav Andersson</a>, <a href="/search/quant-ph?searchtype=author&query=Anferov%2C+A">Alexander Anferov</a>, <a href="/search/quant-ph?searchtype=author&query=Chou%2C+M">Ming-Han Chou</a>, <a href="/search/quant-ph?searchtype=author&query=Conner%2C+C+R">Christopher R. Conner</a>, <a href="/search/quant-ph?searchtype=author&query=Grebel%2C+J">Joel Grebel</a>, <a href="/search/quant-ph?searchtype=author&query=Joshi%2C+Y+J">Yash J. Joshi</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shiheng Li</a>, <a href="/search/quant-ph?searchtype=author&query=Miller%2C+J+M">Jacob M. Miller</a>, <a href="/search/quant-ph?searchtype=author&query=Povey%2C+R+G">Rhys G. Povey</a>, <a href="/search/quant-ph?searchtype=author&query=Qiao%2C+H">Hong Qiao</a>, <a href="/search/quant-ph?searchtype=author&query=Cleland%2C+A+N">Andrew N. Cleland</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="2407.20134v2-abstract-short" style="display: inline;"> Superconducting qubits provide a promising approach to large-scale fault-tolerant quantum computing. However, qubit connectivity on a planar surface is typically restricted to only a few neighboring qubits. Achieving longer-range and more flexible connectivity, which is particularly appealing in light of recent developments in error-correcting codes, however usually involves complex multi-layer pa… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.20134v2-abstract-full').style.display = 'inline'; document.getElementById('2407.20134v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.20134v2-abstract-full" style="display: none;"> Superconducting qubits provide a promising approach to large-scale fault-tolerant quantum computing. However, qubit connectivity on a planar surface is typically restricted to only a few neighboring qubits. Achieving longer-range and more flexible connectivity, which is particularly appealing in light of recent developments in error-correcting codes, however usually involves complex multi-layer packaging and external cabling, which is resource-intensive and can impose fidelity limitations. Here, we propose and realize a high-speed on-chip quantum processor that supports reconfigurable all-to-all coupling with a large on-off ratio. We implement the design in a four-node quantum processor, built with a modular design comprising a wiring substrate coupled to two separate qubit-bearing substrates, each including two single-qubit nodes. We use this device to demonstrate reconfigurable controlled-Z gates across all qubit pairs, with a benchmarked average fidelity of $96.00\%\pm0.08\%$ and best fidelity of $97.14\%\pm0.07\%$, limited mainly by dephasing in the qubits. We also generate multi-qubit entanglement, distributed across the separate modules, demonstrating GHZ-3 and GHZ-4 states with fidelities of $88.15\%\pm0.24\%$ and $75.18\%\pm0.11\%$, respectively. This approach promises efficient scaling to larger-scale quantum circuits, and offers a pathway for implementing quantum algorithms and error correction schemes that benefit from enhanced qubit connectivity. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.20134v2-abstract-full').style.display = 'none'; document.getElementById('2407.20134v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 29 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/2407.19766">arXiv:2407.19766</a> <span> [<a href="https://arxiv.org/pdf/2407.19766">pdf</a>, <a href="https://arxiv.org/format/2407.19766">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Gases">cond-mat.quant-gas</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Superconductivity">cond-mat.supr-con</span> </div> </div> <p class="title is-5 mathjax"> Anomalous symmetry protected blockade of skin effect in one-dimensional non-Hermitian lattice systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shuai Li</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+M">Min Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Y">Yue Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Tian%2C+R">Rui Tian</a>, <a href="/search/quant-ph?searchtype=author&query=Arzamasovs%2C+M">Maksims Arzamasovs</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+B">Bo Liu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2407.19766v1-abstract-short" style="display: inline;"> The non-Hermitian skin effect (NHSE), an anomalous localization behavior of the bulk states, is an inherently non-Hermitian phenomenon, which can not find a counterpart in Hermitian systems. However, the fragility of NHSE has been revealed recently, such as the boundary sensitivity, and it stimulates a lot of studies on discussing the fate of that. Here we present a theorem which shows that the co… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.19766v1-abstract-full').style.display = 'inline'; document.getElementById('2407.19766v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.19766v1-abstract-full" style="display: none;"> The non-Hermitian skin effect (NHSE), an anomalous localization behavior of the bulk states, is an inherently non-Hermitian phenomenon, which can not find a counterpart in Hermitian systems. However, the fragility of NHSE has been revealed recently, such as the boundary sensitivity, and it stimulates a lot of studies on discussing the fate of that. Here we present a theorem which shows that the combined spatial reflection symmetry can be considered as a criterion in one-dimensional non-Hermitian systems to determine whether the NHSE can exist or not. Distinct from previous studies, our proposed criterion only relies on analyzing the symmetry of the system, freeing out other requirements, such as the information of the energy spectrum. Furthermore, by taking the non-Hermitian Kitaev chain as an example, we verify our theorem through both a mathematical proof via the non-Bloch band theory and the exact diagonalization numerical studies. Our results reveal a profound connection between the symmetry and the fate of NHSE. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.19766v1-abstract-full').style.display = 'none'; document.getElementById('2407.19766v1-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 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">7 pages, 2 figures, including Supplementary Material</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.18485">arXiv:2407.18485</a> <span> [<a href="https://arxiv.org/pdf/2407.18485">pdf</a>, <a href="https://arxiv.org/format/2407.18485">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Gases">cond-mat.quant-gas</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"> Non-chiral non-Bloch invariants and topological phase diagram in non-unitary quantum dynamics without chiral symmetry </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Y">Yue Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shuai Li</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+Y">Yingchao Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Tian%2C+R">Rui Tian</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+M">Miao Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+H">Hongrong Li</a>, <a href="/search/quant-ph?searchtype=author&query=Gao%2C+H">Hong Gao</a>, <a href="/search/quant-ph?searchtype=author&query=Zubairy%2C+M+S">M. Suhail Zubairy</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+F">Fuli Li</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+B">Bo Liu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2407.18485v1-abstract-short" style="display: inline;"> The non-Bloch topology leads to the emergence of various counter-intuitive phenomena in non-Hermitian systems under the open boundary condition (OBC), which can not find a counterpart in Hermitian systems. However, in the non-Hermitian system without chiral symmetry, being ubiquitous in nature, exploring its non-Bloch topology has so far eluded experimental effort. Here by introducing the concept… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.18485v1-abstract-full').style.display = 'inline'; document.getElementById('2407.18485v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.18485v1-abstract-full" style="display: none;"> The non-Bloch topology leads to the emergence of various counter-intuitive phenomena in non-Hermitian systems under the open boundary condition (OBC), which can not find a counterpart in Hermitian systems. However, in the non-Hermitian system without chiral symmetry, being ubiquitous in nature, exploring its non-Bloch topology has so far eluded experimental effort. Here by introducing the concept of non-chiral non-Bloch invariants, we theoretically predict and experimentally identify the non-Bloch topological phase diagram of a one-dimensional (1D) non-Hermitian system without chiral symmetry in discrete-time non-unitary quantum walks of single photons. Interestingly, we find that such topological invariants not only can distinguish topologically distinct gapped phases, but also faithfully capture the corresponding gap closing in open-boundary spectrum at the phase boundary. Different topological regions are experimentally identified by measuring the featured discontinuities of the higher moments of the walker's displacement, which amazingly match excellently with our defined non-Bloch invariants. Our work provides a useful platform to study the interplay among topology, symmetries and the non-Hermiticity. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.18485v1-abstract-full').style.display = 'none'; document.getElementById('2407.18485v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 25 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">10 pages, 5 figures, including Supplementary Material</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.03249">arXiv:2407.03249</a> <span> [<a href="https://arxiv.org/pdf/2407.03249">pdf</a>, <a href="https://arxiv.org/format/2407.03249">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Gases">cond-mat.quant-gas</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Atomic Physics">physics.atom-ph</span> </div> </div> <p class="title is-5 mathjax"> Quantum coarsening and collective dynamics on a programmable quantum simulator </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Manovitz%2C+T">Tom Manovitz</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S+H">Sophie H. Li</a>, <a href="/search/quant-ph?searchtype=author&query=Ebadi%2C+S">Sepehr Ebadi</a>, <a href="/search/quant-ph?searchtype=author&query=Samajdar%2C+R">Rhine Samajdar</a>, <a href="/search/quant-ph?searchtype=author&query=Geim%2C+A+A">Alexandra A. Geim</a>, <a href="/search/quant-ph?searchtype=author&query=Evered%2C+S+J">Simon J. Evered</a>, <a href="/search/quant-ph?searchtype=author&query=Bluvstein%2C+D">Dolev Bluvstein</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+H">Hengyun Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Koyluoglu%2C+N+U">Nazli Ugur Koyluoglu</a>, <a href="/search/quant-ph?searchtype=author&query=Feldmeier%2C+J">Johannes Feldmeier</a>, <a href="/search/quant-ph?searchtype=author&query=Dolgirev%2C+P+E">Pavel E. Dolgirev</a>, <a href="/search/quant-ph?searchtype=author&query=Maskara%2C+N">Nishad Maskara</a>, <a href="/search/quant-ph?searchtype=author&query=Kalinowski%2C+M">Marcin Kalinowski</a>, <a href="/search/quant-ph?searchtype=author&query=Sachdev%2C+S">Subir Sachdev</a>, <a href="/search/quant-ph?searchtype=author&query=Huse%2C+D+A">David A. Huse</a>, <a href="/search/quant-ph?searchtype=author&query=Greiner%2C+M">Markus Greiner</a>, <a href="/search/quant-ph?searchtype=author&query=Vuleti%C4%87%2C+V">Vladan Vuleti膰</a>, <a href="/search/quant-ph?searchtype=author&query=Lukin%2C+M+D">Mikhail D. Lukin</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="2407.03249v2-abstract-short" style="display: inline;"> Understanding the collective quantum dynamics of nonequilibrium many-body systems is an outstanding challenge in quantum science. In particular, dynamics driven by quantum fluctuations are important for the formation of exotic quantum phases of matter, fundamental high-energy processes, quantum metrology, and quantum algorithms. Here, we use a programmable quantum simulator based on Rydberg atom a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.03249v2-abstract-full').style.display = 'inline'; document.getElementById('2407.03249v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.03249v2-abstract-full" style="display: none;"> Understanding the collective quantum dynamics of nonequilibrium many-body systems is an outstanding challenge in quantum science. In particular, dynamics driven by quantum fluctuations are important for the formation of exotic quantum phases of matter, fundamental high-energy processes, quantum metrology, and quantum algorithms. Here, we use a programmable quantum simulator based on Rydberg atom arrays to experimentally study collective dynamics across a (2+1)D Ising quantum phase transition. After crossing the quantum critical point, we observe a gradual growth of correlations through coarsening of antiferromagnetically ordered domains. By deterministically preparing and following the evolution of ordered domains, we show that the coarsening is driven by the curvature of domain boundaries, and find that the dynamics accelerate with proximity to the quantum critical point. We quantitatively explore these phenomena and further observe long-lived oscillations of the order parameter, corresponding to an amplitude (Higgs) mode. These observations offer a unique viewpoint into emergent collective dynamics in strongly correlated quantum systems and nonequilibrium quantum processes. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.03249v2-abstract-full').style.display = 'none'; document.getElementById('2407.03249v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 28 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 3 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">25 pages, 15 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.01372">arXiv:2407.01372</a> <span> [<a href="https://arxiv.org/pdf/2407.01372">pdf</a>, <a href="https://arxiv.org/format/2407.01372">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Disordered Systems and Neural Networks">cond-mat.dis-nn</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div 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.110.134203">10.1103/PhysRevB.110.134203 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Asymmetric transfer matrix analysis of Lyapunov exponents in one-dimensional non-reciprocal quasicrystals </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shan-Zhong Li</a>, <a href="/search/quant-ph?searchtype=author&query=Cheng%2C+E">Enhong Cheng</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+S">Shi-Liang Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zhi Li</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2407.01372v2-abstract-short" style="display: inline;"> The Lyapunov exponent, serving as an indicator of the localized state, is commonly utilized to identify localization transitions in disordered systems. In non-Hermitian quasicrystals, the non-Hermitian effect induced by non-reciprocal hopping can lead to the manifestation of two distinct Lyapunov exponents on opposite sides of the localization center. Building on this observation, we here introduc… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.01372v2-abstract-full').style.display = 'inline'; document.getElementById('2407.01372v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.01372v2-abstract-full" style="display: none;"> The Lyapunov exponent, serving as an indicator of the localized state, is commonly utilized to identify localization transitions in disordered systems. In non-Hermitian quasicrystals, the non-Hermitian effect induced by non-reciprocal hopping can lead to the manifestation of two distinct Lyapunov exponents on opposite sides of the localization center. Building on this observation, we here introduce a comprehensive approach for examining the localization characteristics and mobility edges of non-reciprocal quasicrystals, referred to as asymmetric transfer matrix analysis. We demonstrate the application of this method to three specific scenarios: the non-reciprocal Aubry-Andr茅 model, the non-reciprocal off-diagonal Aubry-Andr茅 model, and the non-reciprocal mosaic quasicrystals. This work may contribute valuable insights to the investigation of non-Hermitian quasicrystal and disordered systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.01372v2-abstract-full').style.display = 'none'; document.getElementById('2407.01372v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 20 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 1 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">12 pages, 4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 110, 134203 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2406.19167">arXiv:2406.19167</a> <span> [<a href="https://arxiv.org/pdf/2406.19167">pdf</a>, <a href="https://arxiv.org/format/2406.19167">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/0256-307X/41/7/070302">10.1088/0256-307X/41/7/070302 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Quantum voting machine encoded with microwave photons </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Y">Yu Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+C">Chuiping Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Su%2C+Q">Qiping Su</a>, <a href="/search/quant-ph?searchtype=author&query=Kang%2C+Y">Yihao Kang</a>, <a href="/search/quant-ph?searchtype=author&query=Zheng%2C+W">Wen Zheng</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shaoxiong Li</a>, <a href="/search/quant-ph?searchtype=author&query=Yu%2C+Y">Yang Yu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2406.19167v1-abstract-short" style="display: inline;"> We propose a simple quantum voting machine using microwave photon qubit encoding, based on a setup comprising multiple microwave cavities and a coupled superconducting flux qutrit. This approach primarily relies on a multi-control single-target quantum phase gate. The scheme offers operational simplicity, requiring only a single step, while ensuring verifiability through the measurement of a singl… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.19167v1-abstract-full').style.display = 'inline'; document.getElementById('2406.19167v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2406.19167v1-abstract-full" style="display: none;"> We propose a simple quantum voting machine using microwave photon qubit encoding, based on a setup comprising multiple microwave cavities and a coupled superconducting flux qutrit. This approach primarily relies on a multi-control single-target quantum phase gate. The scheme offers operational simplicity, requiring only a single step, while ensuring verifiability through the measurement of a single qubit phase information to obtain the voting results. And it provides voter anonymity, as the voting outcome is solely tied to the total number of affirmative votes. Our quantum voting machine also has scalability in terms of the number of voters. Additionally, the physical realization of the quantum voting machine is general and not limited to circuit QED. Quantum voting machine can be implemented as long as the multi-control single-phase quantum phase gate is realized in other physical systems. Numerical simulations indicate the feasibility of this quantum voting machine within the current quantum technology. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.19167v1-abstract-full').style.display = 'none'; document.getElementById('2406.19167v1-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 June, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">14pages,4 figures. arXiv admin note: text overlap with arXiv:2306.02227</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">MSC Class:</span> 81V99 </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Chin. Phys. Lett. 41 070302 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2406.14166">arXiv:2406.14166</a> <span> [<a href="https://arxiv.org/pdf/2406.14166">pdf</a>, <a href="https://arxiv.org/format/2406.14166">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.202400140">10.1002/qute.202400140 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Discrete-Modulated Continuous-Variable Quantum Key Distribution in Satellite-to-Ground Communication </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shi-Gen Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+C">Chen-Long Li</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+W">Wen-Bo Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Yin%2C+H">Hua-Lei Yin</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Z">Zeng-Bing Chen</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2406.14166v1-abstract-short" style="display: inline;"> Satellite-to-ground quantum communication constitutes the cornerstone of the global quantum network, heralding the advent of the future of quantum information. Continuous-variable quantum key distribution is a strong candidate for space-ground quantum communication due to its simplicity, stability, and ease of implementation, especially for the robustness of space background light noise. Recently,… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.14166v1-abstract-full').style.display = 'inline'; document.getElementById('2406.14166v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2406.14166v1-abstract-full" style="display: none;"> Satellite-to-ground quantum communication constitutes the cornerstone of the global quantum network, heralding the advent of the future of quantum information. Continuous-variable quantum key distribution is a strong candidate for space-ground quantum communication due to its simplicity, stability, and ease of implementation, especially for the robustness of space background light noise. Recently, the discrete-modulated continuous-variable protocol has garnered increased attention, owing to its lower implementation requirements, acceptable security key rate, and pronounced compatibility with extant infrastructures. Here, we derive key rates for discrete-modulated continuous-variable quantum key distribution protocols in free-space channel environments across various conditions through numerical simulation, revealing the viability of its application in satellite-to-ground communication. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.14166v1-abstract-full').style.display = 'none'; document.getElementById('2406.14166v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 20 June, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">12 pages, 6 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Advanced Quantum Technologies 7, 2400140 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2406.02391">arXiv:2406.02391</a> <span> [<a href="https://arxiv.org/pdf/2406.02391">pdf</a>, <a href="https://arxiv.org/format/2406.02391">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Gases">cond-mat.quant-gas</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Atomic Physics">physics.atom-ph</span> </div> </div> <p class="title is-5 mathjax"> Demonstration of Erasure Conversion in a Molecular Tweezer Array </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Holland%2C+C+M">Connor M. Holland</a>, <a href="/search/quant-ph?searchtype=author&query=Lu%2C+Y">Yukai Lu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S+J">Samuel J. Li</a>, <a href="/search/quant-ph?searchtype=author&query=Welsh%2C+C+L">Callum L. Welsh</a>, <a href="/search/quant-ph?searchtype=author&query=Cheuk%2C+L+W">Lawrence W. Cheuk</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="2406.02391v1-abstract-short" style="display: inline;"> Programmable optical tweezer arrays of molecules are an emerging platform for quantum simulation and quantum information science. For these applications, reducing and mitigating errors that arise during initial state preparation and subsequent evolution remain major challenges. In this paper, we present work on site-resolved detection of internal state errors and quantum erasures, which are qubit… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.02391v1-abstract-full').style.display = 'inline'; document.getElementById('2406.02391v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2406.02391v1-abstract-full" style="display: none;"> Programmable optical tweezer arrays of molecules are an emerging platform for quantum simulation and quantum information science. For these applications, reducing and mitigating errors that arise during initial state preparation and subsequent evolution remain major challenges. In this paper, we present work on site-resolved detection of internal state errors and quantum erasures, which are qubit errors with known locations. First, using a new site-resolved detection scheme, we demonstrate robust and enhanced tweezer array preparation fidelities. This enables creating molecular arrays with low defect rates, opening the door to high-fidelity simulation of quantum many-body systems. Second, for the first time in molecules, we demonstrate mid-circuit detection of erasures using a composite detection scheme that minimally affects error-free qubits. We also demonstrate mid-circuit conversion of blackbody-induced errors into detectable erasures. Our demonstration of erasure conversion, which has been shown to significantly reduce overheads for fault-tolerant quantum error correction, could be useful for quantum information processing in molecular tweezer arrays. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.02391v1-abstract-full').style.display = 'none'; document.getElementById('2406.02391v1-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> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">11 pages, 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/2405.19891">arXiv:2405.19891</a> <span> [<a href="https://arxiv.org/pdf/2405.19891">pdf</a>, <a href="https://arxiv.org/format/2405.19891">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="Information Theory">cs.IT</span> </div> </div> <p class="title is-5 mathjax"> Improving the Fidelity of CNOT Circuits on NISQ Hardware </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Kim%2C+D">Dohun Kim</a>, <a href="/search/quant-ph?searchtype=author&query=Kim%2C+M">Minyoung Kim</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S+M">Sarah Meng Li</a>, <a href="/search/quant-ph?searchtype=author&query=Mosca%2C+M">Michele Mosca</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="2405.19891v1-abstract-short" style="display: inline;"> We introduce an improved CNOT synthesis algorithm that considers nearest-neighbour interactions and CNOT gate error rates in noisy intermediate-scale quantum (NISQ) hardware. Compared to IBM's Qiskit compiler, it improves the fidelity of a synthesized CNOT circuit by about 2 times on average (up to 9 times). It lowers the synthesized CNOT count by a factor of 13 on average (up to a factor of 162).… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.19891v1-abstract-full').style.display = 'inline'; document.getElementById('2405.19891v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.19891v1-abstract-full" style="display: none;"> We introduce an improved CNOT synthesis algorithm that considers nearest-neighbour interactions and CNOT gate error rates in noisy intermediate-scale quantum (NISQ) hardware. Compared to IBM's Qiskit compiler, it improves the fidelity of a synthesized CNOT circuit by about 2 times on average (up to 9 times). It lowers the synthesized CNOT count by a factor of 13 on average (up to a factor of 162). Our contribution is twofold. First, we define a $\textsf{Cost}$ function by approximating the average gate fidelity $F_{avg}$. According to the simulation results, $\textsf{Cost}$ fits the error probability of a noisy CNOT circuit, $\textsf{Prob} = 1 - F_{avg}$, much tighter than the commonly used cost functions. On IBM's fake Nairobi backend, it matches $\textsf{Prob}$ to within $10^{-3}$. On other backends, it fits $\textsf{Prob}$ to within $10^{-1}$. $\textsf{Cost}$ accurately quantifies the dynamic error characteristics and shows remarkable scalability. Second, we propose a noise-aware CNOT routing algorithm, NAPermRowCol, by adapting the leading Steiner-tree-based connectivity-aware CNOT synthesis algorithms. A weighted edge is used to encode a CNOT gate error rate and $\textsf{Cost}$-instructed heuristics are applied to each reduction step. NAPermRowCol does not use ancillary qubits and is not restricted to certain initial qubit maps. Compared with algorithms that are noise-agnostic, it improves the fidelity of a synthesized CNOT circuit across varied NISQ hardware. Depending on the benchmark circuit and the IBM backend selected, it lowers the synthesized CNOT count up to $56.95\%$ compared to ROWCOL and up to $21.62\%$ compared to PermRowCol. It reduces the synthesis $\textsf{Cost}$ up to $25.71\%$ compared to ROWCOL and up to $9.12\%$ compared to PermRowCol. Our method can be extended to route a more general quantum circuit, giving a powerful new tool for compiling on NISQ devices. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.19891v1-abstract-full').style.display = 'none'; document.getElementById('2405.19891v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2024. </p> <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">67 pages, 33 figures, and 9 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/2405.16558">arXiv:2405.16558</a> <span> [<a href="https://arxiv.org/pdf/2405.16558">pdf</a>, <a href="https://arxiv.org/format/2405.16558">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> </div> </div> <p class="title is-5 mathjax"> Experimental Refrence-Frame-Independent Quantum Key Distribution over 250 km of Optical Fiber </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Liu%2C+X">Xin Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Luo%2C+D">Di Luo</a>, <a href="/search/quant-ph?searchtype=author&query=Luo%2C+Z">Zhicheng Luo</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shizhuo Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Z">Zhenrong Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Wei%2C+K">Kejin Wei</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="2405.16558v1-abstract-short" style="display: inline;"> The reference-frame-independent quantum key distribution (RFI-QKD) protocol enables QKD systems to function effectively despite slowly varying reference frames, offering a distinct advantage in practical scenarios, particularly in mobile platforms. In this study, we successfully distribute secure key bits over a 250 km optical fiber distance by developing an RFI-QKD system with a repetition rate o… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.16558v1-abstract-full').style.display = 'inline'; document.getElementById('2405.16558v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.16558v1-abstract-full" style="display: none;"> The reference-frame-independent quantum key distribution (RFI-QKD) protocol enables QKD systems to function effectively despite slowly varying reference frames, offering a distinct advantage in practical scenarios, particularly in mobile platforms. In this study, we successfully distribute secure key bits over a 250 km optical fiber distance by developing an RFI-QKD system with a repetition rate of 150 MHz. Benefiting from high repetition rate, we achieve a finite-key secret key rate of 49.65 bit/s at a distance of 200 km, which is more than three times higher than state-of-the-art systems. Our work dramatically extends the transmission distance and enhances the secret key rate of RFI-QKD, significantly promoting its practical application. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.16558v1-abstract-full').style.display = 'none'; document.getElementById('2405.16558v1-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> 26 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">9 pages,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/2405.10451">arXiv:2405.10451</a> <span> [<a href="https://arxiv.org/pdf/2405.10451">pdf</a>, <a href="https://arxiv.org/ps/2405.10451">ps</a>, <a href="https://arxiv.org/format/2405.10451">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.109.062603">10.1103/PhysRevA.109.062603 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Simulation of a feedback-based algorithm for quantum optimization for a realistic neutral atom system with an optimized small-angle controlled-phase gate </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+S+X">S. X. Li</a>, <a href="/search/quant-ph?searchtype=author&query=Mu%2C+W+L">W. L. Mu</a>, <a href="/search/quant-ph?searchtype=author&query=You%2C+J+B">J. B. You</a>, <a href="/search/quant-ph?searchtype=author&query=Shao%2C+X+Q">X. Q. 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="2405.10451v3-abstract-short" style="display: inline;"> In contrast to the classical optimization process required by the quantum approximate optimization algorithm, FALQON, a feedback-based algorithm for quantum optimization [A. B. Magann {\it et al.,} {\color{blue}Phys. Rev. Lett. {\bf129}, 250502 (2022)}], enables one to obtain approximate solutions to combinatorial optimization problems without any classical optimization effort. In this study, we l… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.10451v3-abstract-full').style.display = 'inline'; document.getElementById('2405.10451v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.10451v3-abstract-full" style="display: none;"> In contrast to the classical optimization process required by the quantum approximate optimization algorithm, FALQON, a feedback-based algorithm for quantum optimization [A. B. Magann {\it et al.,} {\color{blue}Phys. Rev. Lett. {\bf129}, 250502 (2022)}], enables one to obtain approximate solutions to combinatorial optimization problems without any classical optimization effort. In this study, we leverage the specifications of a recent experimental platform for the neutral atom system [Z. Fu {\it et al.,} {\color{blue}Phys. Rev. A {\bf105}, 042430 (2022)}] and present a scheme to implement an optimally tuned small-angle controlled-phase gate. By examining the 2- to 4-qubit FALQON algorithms in the Max-Cut problem and considering the spontaneous emission of the neutral atomic system, we have observed that the performance of FALQON implemented with small-angle controlled-phase gates exceeds that of FALQON utilizing CZ gates. This approach has the potential to significantly simplify the logic circuit required to simulate FALQON and effectively address the Max-Cut problem, which may pave a way for the experimental implementation of near-term noisy intermediate-scale quantum algorithms with neutral-atom systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.10451v3-abstract-full').style.display = 'none'; document.getElementById('2405.10451v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 June, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 16 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">typos corrected and figures updated</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, 062603 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2405.09033">arXiv:2405.09033</a> <span> [<a href="https://arxiv.org/pdf/2405.09033">pdf</a>, <a href="https://arxiv.org/format/2405.09033">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Distributed, Parallel, and Cluster Computing">cs.DC</span> </div> <div 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/10.1109/QSW62656.2024.00025">10.1109/QSW62656.2024.00025 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Accelerating Decision Diagram-based Multi-node Quantum Simulation with Ring Communication and Automatic SWAP Insertion </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Kimura%2C+Y">Yusuke Kimura</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shaowen Li</a>, <a href="/search/quant-ph?searchtype=author&query=Sato%2C+H">Hiroyuki Sato</a>, <a href="/search/quant-ph?searchtype=author&query=Fujita%2C+M">Masahiro Fujita</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="2405.09033v1-abstract-short" style="display: inline;"> An N-bit quantum state requires a vector of length $2^N$, leading to an exponential increase in the required memory with N in conventional statevector-based quantum simulators. A proposed solution to this issue is the decision diagram-based quantum simulator, which can significantly decrease the necessary memory and is expected to operate faster for specific quantum circuits. However, decision dia… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.09033v1-abstract-full').style.display = 'inline'; document.getElementById('2405.09033v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.09033v1-abstract-full" style="display: none;"> An N-bit quantum state requires a vector of length $2^N$, leading to an exponential increase in the required memory with N in conventional statevector-based quantum simulators. A proposed solution to this issue is the decision diagram-based quantum simulator, which can significantly decrease the necessary memory and is expected to operate faster for specific quantum circuits. However, decision diagram-based quantum simulators are not easily parallelizable because data must be manipulated dynamically, and most implementations run on one thread. This paper introduces ring communication-based optimal parallelization and automatic swap insertion techniques for multi-node implementation of decision diagram-based quantum simulators. The ring communication approach is designed so that each node communicates with its neighboring nodes, which can facilitate faster and more parallel communication than broadcasting where one node needs to communicate with all nodes simultaneously. The automatic swap insertion method, an approach to minimize inter-node communication, has been employed in existing multi-node state vector-based simulators, but this paper proposes two methods specifically designed for decision diagram-based quantum simulators. These techniques were implemented and evaluated using the Shor algorithm and random circuits with up to 38 qubits using a maximum of 256 nodes. The experimental results have revealed that multi-node implementation can reduce run-time by up to 26 times. For example, Shor circuits that need 38 qubits can finish simulation in 147 seconds. Additionally, it was shown that ring communication has a higher speed-up effect than broadcast communication, and the importance of selecting the appropriate automatic swap insertion method was revealed. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.09033v1-abstract-full').style.display = 'none'; document.getElementById('2405.09033v1-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 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">Accepted at IEEE QSW 2024</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2405.01464">arXiv:2405.01464</a> <span> [<a href="https://arxiv.org/pdf/2405.01464">pdf</a>, <a href="https://arxiv.org/format/2405.01464">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"> On-demand shaped photon emission based on a parametrically modulated qubit </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xiang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Sheng-Yong Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+S">Si-Lu Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Mei%2C+Z">Zheng-Yang Mei</a>, <a href="/search/quant-ph?searchtype=author&query=He%2C+Y">Yang He</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+C">Cheng-Lin Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+Y">Yu Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+Y">Yan-Jun Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Liang%2C+G">Gui-Han Liang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+J">Jin-Zhe Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+X">Xiao-Hui Song</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+K">Kai Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Heng%2C+F">Fan Heng</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Y">Yu-Xiang Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Xiang%2C+Z">Zhong-Cheng Xiang</a>, <a href="/search/quant-ph?searchtype=author&query=Zheng%2C+D">Dong-Ning Zheng</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="2405.01464v2-abstract-short" style="display: inline;"> In the circuit quantum electrodynamics architectures, to realize a long-range quantum network mediated by flying photon, it is necessary to shape the temporal profile of emitted photons to achieve high transfer efficiency between two quantum nodes. In this work, we demonstrate a new single-rail and dual-rail time-bin shaped photon generator without additional flux-tunable elements, which can act a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.01464v2-abstract-full').style.display = 'inline'; document.getElementById('2405.01464v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.01464v2-abstract-full" style="display: none;"> In the circuit quantum electrodynamics architectures, to realize a long-range quantum network mediated by flying photon, it is necessary to shape the temporal profile of emitted photons to achieve high transfer efficiency between two quantum nodes. In this work, we demonstrate a new single-rail and dual-rail time-bin shaped photon generator without additional flux-tunable elements, which can act as a quantum interface of a point-to-point quantum network. In our approach, we adopt a qubit-resonator-transmission line configuration, and the effective coupling strength between the qubit and the resonator can be varied by parametrically modulating the qubit frequency. In this way, the coupling is directly proportional to the parametric modulation amplitude and covers a broad tunable range beyond 20 MHz for the sample we used. Additionally, when emitting shaped photons, we find that the spurious frequency shift (-0.4 MHz) due to parametric modulation is small and can be readily calibrated through chirping. We develop an efficient photon field measurement setup based on the data stream processing of GPU. Utilizing this system, we perform photon temporal profile measurement, quantum state tomography of photon field, and quantum process tomography of single-rail quantum state transfer based on a heterodyne measurement scheme. The single-rail encoding state transfer fidelity of shaped photon emission is 90.32%, and that for unshaped photon is 97.20%, respectively. We believe that the fidelity of shaped photon emission is mainly limited by the qubit coherence time. The results demonstrate that our method is hardware efficient, simple to implement, and scalable. It could become a viable tool in a high-quality quantum network utilizing both single-rail and dual-rail time-bin encoding. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.01464v2-abstract-full').style.display = 'none'; document.getElementById('2405.01464v2-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">v1</span> submitted 2 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2404.18456">arXiv:2404.18456</a> <span> [<a href="https://arxiv.org/pdf/2404.18456">pdf</a>, <a href="https://arxiv.org/format/2404.18456">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"> Equivalence Checking of Parameterised Quantum Circuits </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Hong%2C+X">Xin Hong</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+W">Wei-Jia Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Chien%2C+W">Wei-Chen Chien</a>, <a href="/search/quant-ph?searchtype=author&query=Feng%2C+Y">Yuan Feng</a>, <a href="/search/quant-ph?searchtype=author&query=Hsieh%2C+M">Min-Hsiu Hsieh</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Sanjiang Li</a>, <a href="/search/quant-ph?searchtype=author&query=Ying%2C+M">Mingsheng Ying</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="2404.18456v1-abstract-short" style="display: inline;"> Parameterised quantum circuits (PQCs) hold great promise for demonstrating quantum advantages in practical applications of quantum computation. Examples of successful applications include the variational quantum eigensolver, the quantum approximate optimisation algorithm, and quantum machine learning. However, before executing PQCs on real quantum devices, they undergo compilation and optimisation… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.18456v1-abstract-full').style.display = 'inline'; document.getElementById('2404.18456v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2404.18456v1-abstract-full" style="display: none;"> Parameterised quantum circuits (PQCs) hold great promise for demonstrating quantum advantages in practical applications of quantum computation. Examples of successful applications include the variational quantum eigensolver, the quantum approximate optimisation algorithm, and quantum machine learning. However, before executing PQCs on real quantum devices, they undergo compilation and optimisation procedures. Given the inherent error-proneness of these processes, it becomes crucial to verify the equivalence between the original PQC and its compiled or optimised version. Unfortunately, most existing quantum circuit verifiers cannot directly handle parameterised quantum circuits; instead, they require parameter substitution to perform verification. In this paper, we address the critical challenge of equivalence checking for PQCs. We propose a novel compact representation for PQCs based on tensor decision diagrams. Leveraging this representation, we present an algorithm for verifying PQC equivalence without the need for instantiation. Our approach ensures both effectiveness and efficiency, as confirmed by experimental evaluations. The decision-diagram representations offer a powerful tool for analysing and verifying parameterised quantum circuits, bridging the gap between theoretical models and practical implementations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.18456v1-abstract-full').style.display = 'none'; document.getElementById('2404.18456v1-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 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/2404.17032">arXiv:2404.17032</a> <span> [<a href="https://arxiv.org/pdf/2404.17032">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="Materials Science">cond-mat.mtrl-sci</span> </div> </div> <p class="title is-5 mathjax"> Quantum bit with telecom wave-length emission from a simple defect in Si </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=De%C3%A1k%2C+P">Peter De谩k</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Song Li</a>, <a href="/search/quant-ph?searchtype=author&query=Gali%2C+A">Adam Gali</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="2404.17032v1-abstract-short" style="display: inline;"> Spin-to-photon interfaces from defects in silicon hold great promise towards realizing quantum repeaters with the combination of advanced semiconductor and photonics technologies. Recently, controlled creation and erasure of simple carbon interstitial defects have been successfully realised in silicon. This defect has a stable structure near room temperature and emits in the wave-length where the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.17032v1-abstract-full').style.display = 'inline'; document.getElementById('2404.17032v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2404.17032v1-abstract-full" style="display: none;"> Spin-to-photon interfaces from defects in silicon hold great promise towards realizing quantum repeaters with the combination of advanced semiconductor and photonics technologies. Recently, controlled creation and erasure of simple carbon interstitial defects have been successfully realised in silicon. This defect has a stable structure near room temperature and emits in the wave-length where the signal loss is minimal in optical fibres used in communication technologies. Our in-depth theoretical characterization confirms the assignment of the observed emission to the neutral charge state of this defect. We find that the emission is due to the recombination of a bound exciton. We also discovered a metastable triplet state that could be applied as a quantum memory. Based on the analysis of the electronic structure of the defect and its similarities to a known optically detected magnetic resonance centre in silicon, we propose that a carbon interstitial can act as a quantum bit and may realize a spin-to-photon interface in CMOS-compatible platforms. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.17032v1-abstract-full').style.display = 'none'; document.getElementById('2404.17032v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 25 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">2 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/2404.12266">arXiv:2404.12266</a> <span> [<a href="https://arxiv.org/pdf/2404.12266">pdf</a>, <a href="https://arxiv.org/format/2404.12266">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Disordered Systems and Neural Networks">cond-mat.dis-nn</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div 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.L041102">10.1103/PhysRevB.110.L041102 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Ring Structure in the Complex Plane: A Fingerprint of non-Hermitian Mobility Edge </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shan-Zhong Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zhi Li</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2404.12266v3-abstract-short" style="display: inline;"> By Avila's global theory, we analytically reveal that the non-Hermitian mobility edge will take on a ring structure in the complex plane, which we name as "mobility ring". The universality of mobility ring has been checked and supported by the Hermitian limit, $PT$-symmetry protection and without $PT$-symmetry cases. Further, we study the evolution of mobility ring versus quasiperiodic strength, a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.12266v3-abstract-full').style.display = 'inline'; document.getElementById('2404.12266v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2404.12266v3-abstract-full" style="display: none;"> By Avila's global theory, we analytically reveal that the non-Hermitian mobility edge will take on a ring structure in the complex plane, which we name as "mobility ring". The universality of mobility ring has been checked and supported by the Hermitian limit, $PT$-symmetry protection and without $PT$-symmetry cases. Further, we study the evolution of mobility ring versus quasiperiodic strength, and find that in the non-Hermitian system, there will appear multiple mobility ring structures. With cross-reference to the multiple mobility edges in Hermitian case, we give the expression of the maximum number of mobility rings. Finally, by comparing the results of Avila's global theorem and self-duality method, we show that self-duality relation has its own limitations in calculating the critical point in non-Hermitian systems. As we know, the general non-Hermitian system has a complex spectrum, which determines that the non-Hermitian mobility edge can but exhibit a ring structure in the complex plane. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.12266v3-abstract-full').style.display = 'none'; document.getElementById('2404.12266v3-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 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 18 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">4.5+4 pages,4+2 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, L041102 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2404.11437">arXiv:2404.11437</a> <span> [<a href="https://arxiv.org/pdf/2404.11437">pdf</a>, <a href="https://arxiv.org/ps/2404.11437">ps</a>, <a href="https://arxiv.org/format/2404.11437">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"> $SO(4)$ Symmetry in Hydrogen Atom with Spin </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Fan%2C+X">Xing-Yan Fan</a>, <a href="/search/quant-ph?searchtype=author&query=Xie%2C+X">Xiang-Ru Xie</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Sheng-Ming Li</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+J">Jing-Ling 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="2404.11437v1-abstract-short" style="display: inline;"> As the simplest atom in nature, the hydrogen atom has been explored thoroughly from the perspective of non-relativistic quantum mechanics to relativistic quantum mechanics. Among the research on hydrogen atom, its energy level is the most basic, which can be obtained more conveniently predicated on the $SO(4)$ symmetry than the wave-equation resolution. Moreover, ``spin'' is another indispensable… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.11437v1-abstract-full').style.display = 'inline'; document.getElementById('2404.11437v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2404.11437v1-abstract-full" style="display: none;"> As the simplest atom in nature, the hydrogen atom has been explored thoroughly from the perspective of non-relativistic quantum mechanics to relativistic quantum mechanics. Among the research on hydrogen atom, its energy level is the most basic, which can be obtained more conveniently predicated on the $SO(4)$ symmetry than the wave-equation resolution. Moreover, ``spin'' is another indispensable topic in quantum mechanics, appearing as an intrinsic degree of freedom. In this work, we generalize the quantum Runge-Lenz vector to a spin-dependent one, and then extract a novel Hamiltonian of hydrogen atom with spin based on the requirement of $SO(4)$ symmetry. Furthermore, the energy spectrum of hydrogen atom with spin potentials is also determined by the remarkable approach of $SO(4)$ symmetry. Our findings extend the ground of hydrogen atom, and may contribute to other complicated models based on hydrogen atom. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.11437v1-abstract-full').style.display = 'none'; document.getElementById('2404.11437v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 17 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">7 pages, 0 figure</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2404.05901">arXiv:2404.05901</a> <span> [<a href="https://arxiv.org/pdf/2404.05901">pdf</a>, <a href="https://arxiv.org/format/2404.05901">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mathematical Physics">math-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Computational Physics">physics.comp-ph</span> </div> </div> <p class="title is-5 mathjax"> Quantum-inspired activation functions and quantum Chebyshev-polynomial network </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shaozhi Li</a>, <a href="/search/quant-ph?searchtype=author&query=Salek%2C+M+S">M Sabbir Salek</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Y">Yao Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Chowdhury%2C+M">Mashrur Chowdhury</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="2404.05901v3-abstract-short" style="display: inline;"> Driven by the significant advantages offered by quantum computing, research in quantum machine learning has increased in recent years. While quantum speed-up has been demonstrated in some applications of quantum machine learning, a comprehensive understanding of its underlying mechanisms for improved performance remains elusive. Our study address this problem by investigating the functional expres… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.05901v3-abstract-full').style.display = 'inline'; document.getElementById('2404.05901v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2404.05901v3-abstract-full" style="display: none;"> Driven by the significant advantages offered by quantum computing, research in quantum machine learning has increased in recent years. While quantum speed-up has been demonstrated in some applications of quantum machine learning, a comprehensive understanding of its underlying mechanisms for improved performance remains elusive. Our study address this problem by investigating the functional expressibility of quantum circuits integrated within a convolutional neural network (CNN). Through numerical experiments on the MNIST, Fashion MNIST, and Letter datasets, our hybrid quantum-classical CNN model demonstrates superior feature selection capabilities and substantially reduces the required training steps compared to classical CNNs. Notably, we observe similar performance improvements when incorporating three other quantum-inspired activation functions in classical neural networks, indicating the benefits of adopting quantum-inspired activation functions. Additionally, we developed a hybrid quantum Chebyshev-polynomial network (QCPN) based on the properties of quantum activation functions. We demonstrate that a three-layer QCPN can approximate any continuous function, a feat not achievable by a standard three-layer classical neural network. Our findings suggest that quantum-inspired activation functions can reduce model depth while maintaining high learning capability, making them a promising approach for optimizing large-scale machine-learning models. We also outline future research directions for leveraging quantum advantages in machine learning, aiming to unlock further potential in this rapidly evolving field. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.05901v3-abstract-full').style.display = 'none'; document.getElementById('2404.05901v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 23 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 8 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">13 pages, 6 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">ACM Class:</span> G.1.6 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.17253">arXiv:2403.17253</a> <span> [<a href="https://arxiv.org/pdf/2403.17253">pdf</a>, <a href="https://arxiv.org/ps/2403.17253">ps</a>, <a href="https://arxiv.org/format/2403.17253">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="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"> Convert laser light into single photons via interference </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yanfeng Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+M">Manman Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+G">Guoqi Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+L">Li Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+W">Wenyan Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Ji%2C+W">Weijie Ji</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+H">Hanqing Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Su%2C+X">Xiangbin Su</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shulun Li</a>, <a href="/search/quant-ph?searchtype=author&query=Dai%2C+D">Deyan Dai</a>, <a href="/search/quant-ph?searchtype=author&query=Shang%2C+X">Xiangjun Shang</a>, <a href="/search/quant-ph?searchtype=author&query=Ni%2C+H">Haiqiao Ni</a>, <a href="/search/quant-ph?searchtype=author&query=Niu%2C+Z">Zhichuan Niu</a>, <a href="/search/quant-ph?searchtype=author&query=Hu%2C+C">Chengyong Hu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2403.17253v1-abstract-short" style="display: inline;"> Laser light possesses perfect coherence, but cannot be attenuated to single photons via linear optics. An elegant route to convert laser light into single photons is based on photon blockade in a cavity with a single atom in the strong coupling regime. However, the single-photon purity achieved by this method remains relatively low. Here we propose an interference-based approach where laser light… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.17253v1-abstract-full').style.display = 'inline'; document.getElementById('2403.17253v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.17253v1-abstract-full" style="display: none;"> Laser light possesses perfect coherence, but cannot be attenuated to single photons via linear optics. An elegant route to convert laser light into single photons is based on photon blockade in a cavity with a single atom in the strong coupling regime. However, the single-photon purity achieved by this method remains relatively low. Here we propose an interference-based approach where laser light can be transformed into single photons by destructively interfering with a weak but super-bunched incoherent field emitted from a cavity coupling to a single quantum emitter. We demonstrate this idea by measuring the reflected light of a laser field which drives a double-sided optical microcavity containing a single artificial atom-quantum dot (QD) in the Purcell regime. The reflected light consists of a superposition of the driving field with the cavity output field. We achieve the second-order autocorrelation g2(0)=0.030+-0.002 and the two-photon interference visibility 94.3%+-0.2. By separating the coherent and incoherent fields in the reflected light, we observe that the incoherent field from the cavity exhibits super-bunching with g2(0)=41+-2 while the coherent field remains Poissonian statistics. By controlling the relative amplitude of coherent and incoherent fields, we verify that photon statistics of reflected light is tuneable from perfect anti-bunching to super-bunching in agreement with our predictions. Our results demonstrate photon statistics of light as a quantum interference phenomenon that a single QD can scatter two photons simultaneously at low driving fields in contrast to the common picture that a single two-level quantum emitter can only scatter (or absorb and emit) single photons. This work opens the door to tailoring photon statistics of laser light via cavity or waveguide quantum electrodynamics and interference. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.17253v1-abstract-full').style.display = 'none'; document.getElementById('2403.17253v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 25 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">Comments are welcome</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.11142">arXiv:2403.11142</a> <span> [<a href="https://arxiv.org/pdf/2403.11142">pdf</a>, <a href="https://arxiv.org/format/2403.11142">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"> Dynamics and Resonance Fluorescence from a Superconducting Artificial Atom Doubly Driven by Quantized and Classical Fields </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Ruan%2C+X">Xinhui Ruan</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+J">Jia-Heng Wang</a>, <a href="/search/quant-ph?searchtype=author&query=He%2C+D">Dong He</a>, <a href="/search/quant-ph?searchtype=author&query=Song%2C+P">Pengtao Song</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shengyong Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+Q">Qianchuan Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Kuang%2C+L+M">L. M. Kuang</a>, <a href="/search/quant-ph?searchtype=author&query=Tsai%2C+J">Jaw-Shen Tsai</a>, <a href="/search/quant-ph?searchtype=author&query=Zou%2C+C">Chang-Ling Zou</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+J">Jing Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Zheng%2C+D">Dongning Zheng</a>, <a href="/search/quant-ph?searchtype=author&query=Astafiev%2C+O+V">O. V. Astafiev</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+Y">Yu-xi Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Peng%2C+Z">Zhihui 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="2403.11142v1-abstract-short" style="display: inline;"> We report an experimental demonstration of resonance fluorescence in a two-level superconducting artificial atom under two driving fields coupled to a detuned cavity. One of the fields is classical and the other is varied from quantum (vacuum fluctuations) to classical one by controlling the photon number inside the cavity. The device consists of a transmon qubit strongly coupled to a one-dimensio… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.11142v1-abstract-full').style.display = 'inline'; document.getElementById('2403.11142v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.11142v1-abstract-full" style="display: none;"> We report an experimental demonstration of resonance fluorescence in a two-level superconducting artificial atom under two driving fields coupled to a detuned cavity. One of the fields is classical and the other is varied from quantum (vacuum fluctuations) to classical one by controlling the photon number inside the cavity. The device consists of a transmon qubit strongly coupled to a one-dimensional transmission line and a coplanar waveguide resonator. We observe a sideband anti-crossing and asymmetry in the emission spectra of the system through a one-dimensional transmission line, which is fundamentally different from the weak coupling case. By changing the photon number inside the cavity, the emission spectrum of our doubly driven system approaches to the case when the atom is driven by two classical bichromatic fields. We also measure the dynamical evolution of the system through the transmission line and study the properties of the first-order correlation function, Rabi oscillations and energy relaxation in the system. The study of resonance fluorescence from an atom driven by two fields promotes understanding decoherence in superconducting quantum circuits and may find applications in superconducting quantum computing and quantum networks. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.11142v1-abstract-full').style.display = 'none'; document.getElementById('2403.11142v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 17 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/2402.09752">arXiv:2402.09752</a> <span> [<a href="https://arxiv.org/pdf/2402.09752">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Systems and Control">eess.SY</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Applied Physics">physics.app-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Vector spectrometer with Hertz-level resolution and super-recognition capability </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Qing%2C+T">Ting Qing</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shupeng Li</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+H">Huashan Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+L">Lihan Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Fang%2C+Y">Yijie Fang</a>, <a href="/search/quant-ph?searchtype=author&query=Tang%2C+X">Xiaohu Tang</a>, <a href="/search/quant-ph?searchtype=author&query=Cao%2C+M">Meihui Cao</a>, <a href="/search/quant-ph?searchtype=author&query=Lu%2C+J">Jianming Lu</a>, <a href="/search/quant-ph?searchtype=author&query=He%2C+J">Jijun He</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+J">Junqiu Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Lyu%2C+Y">Yueguang Lyu</a>, <a href="/search/quant-ph?searchtype=author&query=Pan%2C+S">Shilong 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="2402.09752v2-abstract-short" style="display: inline;"> High-resolution optical spectrometers are crucial in revealing intricate characteristics of signals, determining laser frequencies, measuring physical constants, identifying substances, and advancing biosensing applications. Conventional spectrometers, however, often grapple with inherent trade-offs among spectral resolution, wavelength range, and accuracy. Furthermore, even at high resolution, re… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.09752v2-abstract-full').style.display = 'inline'; document.getElementById('2402.09752v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2402.09752v2-abstract-full" style="display: none;"> High-resolution optical spectrometers are crucial in revealing intricate characteristics of signals, determining laser frequencies, measuring physical constants, identifying substances, and advancing biosensing applications. Conventional spectrometers, however, often grapple with inherent trade-offs among spectral resolution, wavelength range, and accuracy. Furthermore, even at high resolution, resolving overlapping spectral lines during spectroscopic analyses remains a huge challenge. Here, we propose a vector spectrometer with ultrahigh resolution, combining broadband optical frequency hopping, ultrafine microwave-photonic scanning, and vector detection. A programmable frequency-hopping laser was developed, facilitating a sub-Hz linewidth and Hz-level frequency stability, an improvement of four and six orders of magnitude, respectively, compared to those of state-of-the-art tunable lasers. We also designed an asymmetric optical transmitter and receiver to eliminate measurement errors arising from modulation nonlinearity and multi-channel crosstalk. The resultant vector spectrometer exhibits an unprecedented frequency resolution of 2 Hz, surpassing the state-of-the-art by four orders of magnitude, over a 33-nm range. Through high-resolution vector analysis, we observed that group delay information enhances the separation capability of overlapping spectral lines by over 47%, significantly streamlining the real-time identification of diverse substances. Our technique fills the gap in optical spectrometers with resolutions below 10 kHz and enables vector measurement to embrace revolution in functionality. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.09752v2-abstract-full').style.display = 'none'; document.getElementById('2402.09752v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 6 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 15 February, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">21 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/2401.01592">arXiv:2401.01592</a> <span> [<a href="https://arxiv.org/pdf/2401.01592">pdf</a>, <a href="https://arxiv.org/format/2401.01592">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"> Single-photon scattering in giant-atom waveguide systems with chiral coupling </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shu-Yu Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Z">Ze-Quan Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Du%2C+L">Lei Du</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yong Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+H">Huaizhi Wu</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="2401.01592v3-abstract-short" style="display: inline;"> We study single-photon scattering spectra of a giant atom chirally coupled to a one-dimensional waveguide at multiple connection points, and examine chirality induced effects in the scattering spectra. We show that the transmission spectra typically possess an anti-Lorentzian lineshape with a nonzero minimum, but by engineering the chirality of the multi-point coupling, the transmission spectrum o… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.01592v3-abstract-full').style.display = 'inline'; document.getElementById('2401.01592v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2401.01592v3-abstract-full" style="display: none;"> We study single-photon scattering spectra of a giant atom chirally coupled to a one-dimensional waveguide at multiple connection points, and examine chirality induced effects in the scattering spectra. We show that the transmission spectra typically possess an anti-Lorentzian lineshape with a nonzero minimum, but by engineering the chirality of the multi-point coupling, the transmission spectrum of an incident photon can undergo a transition from complete transmission to total reflection at multiple frequency ``windows'', where the width of the anti-Lorentzian lineshape for each of the window can be flexibly tuned at a fixed frequency detuning. Moreover, we show that a perfect nonreciprocal photon scattering can be achieved due to the interplay between internal atomic spontaneous emission and the chirally external decay to the waveguide, in contrast to that induced by the non-Markovian retardation effect. We also consider the non-Markovian retardation effect on the scattering spectra, which allows for a photonic band gap even with only two chiral coupling points. The giant-atom-waveguide system with chiral coupling is a promising candidate for realizing single-photon routers with multiple channels. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.01592v3-abstract-full').style.display = 'none'; document.getElementById('2401.01592v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 3 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, 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/2401.01162">arXiv:2401.01162</a> <span> [<a href="https://arxiv.org/pdf/2401.01162">pdf</a>, <a href="https://arxiv.org/format/2401.01162">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="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"> Can Bell inequalities be tested via scattering cross-section at colliders ? </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Song Li</a>, <a href="/search/quant-ph?searchtype=author&query=Shen%2C+W">Wei Shen</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+J+M">Jin Min 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="2401.01162v3-abstract-short" style="display: inline;"> In current studies for testing Bell inequalities at colliders, the reconstruction of spin correlations from scattering cross-sections relies on the bilinear form of the spin correlations, but not all local hidden variable models (LHVMs) have such a property. To demonstrate that a general LHVM cannot be rule out via scattering cross-section data, we propose a specific LHVM, which can exactly duplic… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.01162v3-abstract-full').style.display = 'inline'; document.getElementById('2401.01162v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2401.01162v3-abstract-full" style="display: none;"> In current studies for testing Bell inequalities at colliders, the reconstruction of spin correlations from scattering cross-sections relies on the bilinear form of the spin correlations, but not all local hidden variable models (LHVMs) have such a property. To demonstrate that a general LHVM cannot be rule out via scattering cross-section data, we propose a specific LHVM, which can exactly duplicate the same scattering cross-section for particle production and decay as the standard quantum theory, making it indistinguishable at colliders in principle. Despite of this, we find that reconstructing spin correlations through scattering cross-sections can still exclude a broad class of LHVMs, e.g., those models employing classical spin correlations as a surrogate for quantum spin correlations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.01162v3-abstract-full').style.display = 'none'; document.getElementById('2401.01162v3-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 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 2 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">14 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/2401.00519">arXiv:2401.00519</a> <span> [<a href="https://arxiv.org/pdf/2401.00519">pdf</a>, <a href="https://arxiv.org/format/2401.00519">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"> Multiplexed entanglement swapping with atomic-ensemble-based quantum memories in the single excitation regime </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wang%2C+M">Minjie Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Jiao%2C+H">Haole Jiao</a>, <a href="/search/quant-ph?searchtype=author&query=Lu%2C+J">Jiajin Lu</a>, <a href="/search/quant-ph?searchtype=author&query=Fan%2C+W">Wenxin Fan</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shujing Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+H">Hai 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="2401.00519v1-abstract-short" style="display: inline;"> Entanglement swapping (ES) between memory repeater links is critical for establishing quantum networks via quantum repeaters. So far, ES with atomic-ensemble-based memories has not been achieved. Here, we experimentally demonstrated ES between two entangled pairs of spin-wave memories via Duan-Lukin-Cirac-Zoller scheme. With a cloud of cold atoms inserted in a cavity, we produce non-classically-co… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.00519v1-abstract-full').style.display = 'inline'; document.getElementById('2401.00519v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2401.00519v1-abstract-full" style="display: none;"> Entanglement swapping (ES) between memory repeater links is critical for establishing quantum networks via quantum repeaters. So far, ES with atomic-ensemble-based memories has not been achieved. Here, we experimentally demonstrated ES between two entangled pairs of spin-wave memories via Duan-Lukin-Cirac-Zoller scheme. With a cloud of cold atoms inserted in a cavity, we produce non-classically-correlated spin-wave-photon pairs in 12 spatial modes and then prepare two entangled pairs of spin-wave memories via a multiplexed scheme. Via single-photon Bell measurement on retrieved fields from two memories, we project the two remaining memories never entangled previously into an entangled state with the measured concurrence of C = 0.0124(0.003). The successful probability of ES in our scheme is increased by three times, compared with that in non-multiplexed scheme. Our presented work shows that the generation of entanglement (C>0) between the remaining memory ensembles requires the average cross-correlation function of the spin-wave-photon pairs to be >30 . <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.00519v1-abstract-full').style.display = 'none'; document.getElementById('2401.00519v1-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> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2312.03982">arXiv:2312.03982</a> <span> [<a href="https://arxiv.org/pdf/2312.03982">pdf</a>, <a href="https://arxiv.org/format/2312.03982">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Gases">cond-mat.quant-gas</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Atomic Physics">physics.atom-ph</span> </div> <div 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/s41586-023-06927-3">10.1038/s41586-023-06927-3 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Logical quantum processor based on reconfigurable atom arrays </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Bluvstein%2C+D">Dolev Bluvstein</a>, <a href="/search/quant-ph?searchtype=author&query=Evered%2C+S+J">Simon J. Evered</a>, <a href="/search/quant-ph?searchtype=author&query=Geim%2C+A+A">Alexandra A. Geim</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S+H">Sophie H. Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+H">Hengyun Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Manovitz%2C+T">Tom Manovitz</a>, <a href="/search/quant-ph?searchtype=author&query=Ebadi%2C+S">Sepehr Ebadi</a>, <a href="/search/quant-ph?searchtype=author&query=Cain%2C+M">Madelyn Cain</a>, <a href="/search/quant-ph?searchtype=author&query=Kalinowski%2C+M">Marcin Kalinowski</a>, <a href="/search/quant-ph?searchtype=author&query=Hangleiter%2C+D">Dominik Hangleiter</a>, <a href="/search/quant-ph?searchtype=author&query=Ataides%2C+J+P+B">J. Pablo Bonilla Ataides</a>, <a href="/search/quant-ph?searchtype=author&query=Maskara%2C+N">Nishad Maskara</a>, <a href="/search/quant-ph?searchtype=author&query=Cong%2C+I">Iris Cong</a>, <a href="/search/quant-ph?searchtype=author&query=Gao%2C+X">Xun Gao</a>, <a href="/search/quant-ph?searchtype=author&query=Rodriguez%2C+P+S">Pedro Sales Rodriguez</a>, <a href="/search/quant-ph?searchtype=author&query=Karolyshyn%2C+T">Thomas Karolyshyn</a>, <a href="/search/quant-ph?searchtype=author&query=Semeghini%2C+G">Giulia Semeghini</a>, <a href="/search/quant-ph?searchtype=author&query=Gullans%2C+M+J">Michael J. Gullans</a>, <a href="/search/quant-ph?searchtype=author&query=Greiner%2C+M">Markus Greiner</a>, <a href="/search/quant-ph?searchtype=author&query=Vuletic%2C+V">Vladan Vuletic</a>, <a href="/search/quant-ph?searchtype=author&query=Lukin%2C+M+D">Mikhail D. Lukin</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="2312.03982v1-abstract-short" style="display: inline;"> Suppressing errors is the central challenge for useful quantum computing, requiring quantum error correction for large-scale processing. However, the overhead in the realization of error-corrected ``logical'' qubits, where information is encoded across many physical qubits for redundancy, poses significant challenges to large-scale logical quantum computing. Here we report the realization of a pro… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.03982v1-abstract-full').style.display = 'inline'; document.getElementById('2312.03982v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2312.03982v1-abstract-full" style="display: none;"> Suppressing errors is the central challenge for useful quantum computing, requiring quantum error correction for large-scale processing. However, the overhead in the realization of error-corrected ``logical'' qubits, where information is encoded across many physical qubits for redundancy, poses significant challenges to large-scale logical quantum computing. Here we report the realization of a programmable quantum processor based on encoded logical qubits operating with up to 280 physical qubits. Utilizing logical-level control and a zoned architecture in reconfigurable neutral atom arrays, our system combines high two-qubit gate fidelities, arbitrary connectivity, as well as fully programmable single-qubit rotations and mid-circuit readout. Operating this logical processor with various types of encodings, we demonstrate improvement of a two-qubit logic gate by scaling surface code distance from d=3 to d=7, preparation of color code qubits with break-even fidelities, fault-tolerant creation of logical GHZ states and feedforward entanglement teleportation, as well as operation of 40 color code qubits. Finally, using three-dimensional [[8,3,2]] code blocks, we realize computationally complex sampling circuits with up to 48 logical qubits entangled with hypercube connectivity with 228 logical two-qubit gates and 48 logical CCZ gates. We find that this logical encoding substantially improves algorithmic performance with error detection, outperforming physical qubit fidelities at both cross-entropy benchmarking and quantum simulations of fast scrambling. These results herald the advent of early error-corrected quantum computation and chart a path toward large-scale logical processors. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.03982v1-abstract-full').style.display = 'none'; document.getElementById('2312.03982v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 6 December, 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">See ancillary files: five supplementary movies and captions. Main text + Methods</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2312.03189">arXiv:2312.03189</a> <span> [<a href="https://arxiv.org/pdf/2312.03189">pdf</a>, <a href="https://arxiv.org/format/2312.03189">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Gases">cond-mat.quant-gas</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevResearch.6.L022003">10.1103/PhysRevResearch.6.L022003 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> $n$-body anti-bunching in a degenerate Fermi gas of $^3$He* atoms </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Thomas%2C+K+F">Kieran F. Thomas</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shijie Li</a>, <a href="/search/quant-ph?searchtype=author&query=Abbas%2C+A+H">A. H. Abbas</a>, <a href="/search/quant-ph?searchtype=author&query=Truscott%2C+A+G">Andrew G. Truscott</a>, <a href="/search/quant-ph?searchtype=author&query=Hodgman%2C+S+S">Sean. S. Hodgman</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="2312.03189v1-abstract-short" style="display: inline;"> A key observable in investigations into quantum systems are the $n$-body correlation functions, which provide a powerful tool for experimentally determining coherence and directly probing the many-body wavefunction. While the (bosonic) correlations of photonic systems are well explored, the correlations present in matter-wave systems, particularly for fermionic atoms, are still an emerging field.… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.03189v1-abstract-full').style.display = 'inline'; document.getElementById('2312.03189v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2312.03189v1-abstract-full" style="display: none;"> A key observable in investigations into quantum systems are the $n$-body correlation functions, which provide a powerful tool for experimentally determining coherence and directly probing the many-body wavefunction. While the (bosonic) correlations of photonic systems are well explored, the correlations present in matter-wave systems, particularly for fermionic atoms, are still an emerging field. In this work, we use the unique single-atom detection properties of $^3$He* atoms to perform simultaneous measurements of the $n$-body quantum correlations, up to the fifth-order, of a degenerate Fermi gas. In a direct demonstration of the Pauli exclusion principle, we observe clear anti-bunching at all orders and find good agreement with predicted correlation volumes. Our results pave the way for using correlation functions to probe some of the rich physics associated with fermionic systems, such as d-wave pairing in superconductors. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.03189v1-abstract-full').style.display = 'none'; document.getElementById('2312.03189v1-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> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">11 pages, 7 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Research 6, L022003 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2312.01570">arXiv:2312.01570</a> <span> [<a href="https://arxiv.org/pdf/2312.01570">pdf</a>, <a href="https://arxiv.org/format/2312.01570">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Distributed, Parallel, and Cluster Computing">cs.DC</span> </div> <div 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/10.1109/QSW59989.2023.00026">10.1109/QSW59989.2023.00026 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Parallelizing quantum simulation with decision diagrams </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shaowen Li</a>, <a href="/search/quant-ph?searchtype=author&query=Kimura%2C+Y">Yusuke Kimura</a>, <a href="/search/quant-ph?searchtype=author&query=Sato%2C+H">Hiroyuki Sato</a>, <a href="/search/quant-ph?searchtype=author&query=Yu%2C+J">Junwei Yu</a>, <a href="/search/quant-ph?searchtype=author&query=Fujita%2C+M">Masahiro Fujita</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="2312.01570v1-abstract-short" style="display: inline;"> Recent technological advancements show promise in leveraging quantum mechanical phenomena for computation. This brings substantial speed-ups to problems that are once considered to be intractable in the classical world. However, the physical realization of quantum computers is still far away from us, and a majority of research work is done using quantum simulators running on classical computers. C… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.01570v1-abstract-full').style.display = 'inline'; document.getElementById('2312.01570v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2312.01570v1-abstract-full" style="display: none;"> Recent technological advancements show promise in leveraging quantum mechanical phenomena for computation. This brings substantial speed-ups to problems that are once considered to be intractable in the classical world. However, the physical realization of quantum computers is still far away from us, and a majority of research work is done using quantum simulators running on classical computers. Classical computers face a critical obstacle in simulating quantum algorithms. Quantum states reside in a Hilbert space whose size grows exponentially to the number of subsystems, i.e., qubits. As a result, the straightforward statevector approach does not scale due to the exponential growth of the memory requirement. Decision diagrams have gained attention in recent years for representing quantum states and operations in quantum simulations. The main advantage of this approach is its ability to exploit redundancy. However, mainstream quantum simulators still rely on statevectors or tensor networks. We consider the absence of decision diagrams due to the lack of parallelization strategies. This work explores several strategies for parallelizing decision diagram operations, specifically for quantum simulations. We propose optimal parallelization strategies. Based on the experiment results, our parallelization strategy achieves a 2-3 times faster simulation of Grover's algorithm and random circuits than the state-of-the-art single-thread DD-based simulator DDSIM. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.01570v1-abstract-full').style.display = 'none'; document.getElementById('2312.01570v1-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">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/2311.14277">arXiv:2311.14277</a> <span> [<a href="https://arxiv.org/pdf/2311.14277">pdf</a>, <a href="https://arxiv.org/ps/2311.14277">ps</a>, <a href="https://arxiv.org/format/2311.14277">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Gases">cond-mat.quant-gas</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Anisotropy-induced Coulomb phase and quasiparticle zoo in the atomic monopole-spin hybrid system </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Shao-Jun Li</a>, <a href="/search/quant-ph?searchtype=author&query=Gao%2C+X">Xiang Gao</a>, <a href="/search/quant-ph?searchtype=author&query=Fang%2C+X">Xue-Ting Fang</a>, <a href="/search/quant-ph?searchtype=author&query=Cao%2C+L">Lushuai Cao</a>, <a href="/search/quant-ph?searchtype=author&query=Schmelcher%2C+P">Peter Schmelcher</a>, <a href="/search/quant-ph?searchtype=author&query=Hu%2C+Z">Zhong-Kun Hu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2311.14277v1-abstract-short" style="display: inline;"> Quantum simulation of a monopole-spin hybrid system is performed on basis of a dipolar ultracold gas in a ladder lattice. The site-occupation states of the dipolar ladder lattice gas can spontaneously emulate both the monopole and spin excitations. The hopping of the atoms induces a particle conversion process between spin and monopole pairs, and the dipole-dipole interaction determines the spin-s… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.14277v1-abstract-full').style.display = 'inline'; document.getElementById('2311.14277v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2311.14277v1-abstract-full" style="display: none;"> Quantum simulation of a monopole-spin hybrid system is performed on basis of a dipolar ultracold gas in a ladder lattice. The site-occupation states of the dipolar ladder lattice gas can spontaneously emulate both the monopole and spin excitations. The hopping of the atoms induces a particle conversion process between spin and monopole pairs, and the dipole-dipole interaction determines the spin-spin, spin-monopole and monopole-monopole interactions. The anisotropic nature of the dipole-dipole interaction allows hereby for a flexible engineering of the designed hybrid system, and for a significant tunability of the interaction strengths. As a result, we encounter a rich phase diagram, and specifically a self-assembled Coulomb phase arises, in which monopoles and spins coexist and are orderly arranged according to the local Gauss's law. The Coulomb phase hosts a zoo of different types of quasiparticles, and provides the possibility to simulate various phenomena in particle physics, such as a degenerate vacuum, particle decay and conversion processes. Our work provides a significant extension of the scope of quantum simulations based on the anisotropy of dipolar interactions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.14277v1-abstract-full').style.display = 'none'; document.getElementById('2311.14277v1-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 November, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">11 pages,8 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2311.12362">arXiv:2311.12362</a> <span> [<a href="https://arxiv.org/pdf/2311.12362">pdf</a>, <a href="https://arxiv.org/ps/2311.12362">ps</a>, <a href="https://arxiv.org/format/2311.12362">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="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Genuinely accessible and inaccessible entanglement in Schwarzschild black hole </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wu%2C+S">Shu-Min Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Teng%2C+X">Xiao-Wei Teng</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+J">Jin-Xuan Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Si-Han Li</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+T">Tong-Hua Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+J">Jie-Ci 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="2311.12362v1-abstract-short" style="display: inline;"> The genuine entanglement of Dirac fields for an N-partite system is investigated in Schwarzschild spacetime and the analysis is carried out using the single-mode approximation. Due to the Hawking effect, quantum entanglement is divided into two parts physically accessible and inaccessible entanglement. We obtain a general analytic expression of genuine N-partite entanglement that includes all acce… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.12362v1-abstract-full').style.display = 'inline'; document.getElementById('2311.12362v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2311.12362v1-abstract-full" style="display: none;"> The genuine entanglement of Dirac fields for an N-partite system is investigated in Schwarzschild spacetime and the analysis is carried out using the single-mode approximation. Due to the Hawking effect, quantum entanglement is divided into two parts physically accessible and inaccessible entanglement. We obtain a general analytic expression of genuine N-partite entanglement that includes all accessible and inaccessible entanglement in a Schwarzschild black hole. Unlike bosonic entanglement, the accessible N-partite entanglement of Dirac fields monotonically decreases to a nonzero value with the Hawking temperature. Interestingly, the inaccessible N-partite entanglement is a monotonic or non-monotonic function of the Hawking temperature, depending on the ratio between accessible and inaccessible modes, in contrast to bipartite or tripartite entanglement that is only a monotonic function of the Hawking temperature. Finally, we obtain two restrictive relationships for the quantum information of the black hole. This conclusion provides a new understanding of Hawking effect of the black hole. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.12362v1-abstract-full').style.display = 'none'; document.getElementById('2311.12362v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 November, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2023. </p> <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, 1 figure</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Lett. B 848 (2024) 138334 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2311.03408">arXiv:2311.03408</a> <span> [<a href="https://arxiv.org/pdf/2311.03408">pdf</a>, <a href="https://arxiv.org/format/2311.03408">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Machine Learning">cs.LG</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Artificial Intelligence">cs.AI</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Neural and Evolutionary Computing">cs.NE</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"> Training Multi-layer Neural Networks on Ising Machine </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Song%2C+X">Xujie Song</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+T">Tong Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S+E">Shengbo Eben Li</a>, <a href="/search/quant-ph?searchtype=author&query=Duan%2C+J">Jingliang Duan</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+W">Wenxuan Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+K">Keqiang 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="2311.03408v1-abstract-short" style="display: inline;"> As a dedicated quantum device, Ising machines could solve large-scale binary optimization problems in milliseconds. There is emerging interest in utilizing Ising machines to train feedforward neural networks due to the prosperity of generative artificial intelligence. However, existing methods can only train single-layer feedforward networks because of the complex nonlinear network topology. This… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.03408v1-abstract-full').style.display = 'inline'; document.getElementById('2311.03408v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2311.03408v1-abstract-full" style="display: none;"> As a dedicated quantum device, Ising machines could solve large-scale binary optimization problems in milliseconds. There is emerging interest in utilizing Ising machines to train feedforward neural networks due to the prosperity of generative artificial intelligence. However, existing methods can only train single-layer feedforward networks because of the complex nonlinear network topology. This paper proposes an Ising learning algorithm to train quantized neural network (QNN), by incorporating two essential techinques, namely binary representation of topological network and order reduction of loss function. As far as we know, this is the first algorithm to train multi-layer feedforward networks on Ising machines, providing an alternative to gradient-based backpropagation. Firstly, training QNN is formulated as a quadratic constrained binary optimization (QCBO) problem by representing neuron connection and activation function as equality constraints. All quantized variables are encoded by binary bits based on binary encoding protocol. Secondly, QCBO is converted to a quadratic unconstrained binary optimization (QUBO) problem, that can be efficiently solved on Ising machines. The conversion leverages both penalty function and Rosenberg order reduction, who together eliminate equality constraints and reduce high-order loss function into a quadratic one. With some assumptions, theoretical analysis shows the space complexity of our algorithm is $\mathcal{O}(H^2L + HLN\log H)$, quantifying the required number of Ising spins. Finally, the algorithm effectiveness is validated with a simulated Ising machine on MNIST dataset. After annealing 700 ms, the classification accuracy achieves 98.3%. Among 100 runs, the success probability of finding the optimal solution is 72%. Along with the increasing number of spins on Ising machine, our algorithm has the potential to train deeper neural networks. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.03408v1-abstract-full').style.display = 'none'; document.getElementById('2311.03408v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 November, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2023. </p> </li> </ol> <nav class="pagination is-small is-centered breathe-horizontal" role="navigation" aria-label="pagination"> <a href="" class="pagination-previous is-invisible">Previous </a> <a href="/search/?searchtype=author&query=Li%2C+S&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Li%2C+S&start=0" class="pagination-link is-current" 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