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</div> <div class="control"> <button class="button is-small is-link">Go</button> </div> </div> </form> </div> </div> <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/2410.06557">arXiv:2410.06557</a> <span> [<a href="https://arxiv.org/pdf/2410.06557">pdf</a>, <a href="https://arxiv.org/format/2410.06557">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Disordered Systems and Neural Networks">cond-mat.dis-nn</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Lattice">hep-lat</span> </div> </div> <p class="title is-5 mathjax"> Observation of disorder-free localization and efficient disorder averaging on a quantum processor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Gyawali%2C+G">Gaurav Gyawali</a>, <a href="/search/cond-mat?searchtype=author&query=Cochran%2C+T">Tyler Cochran</a>, <a href="/search/cond-mat?searchtype=author&query=Lensky%2C+Y">Yuri Lensky</a>, <a href="/search/cond-mat?searchtype=author&query=Rosenberg%2C+E">Eliott Rosenberg</a>, <a href="/search/cond-mat?searchtype=author&query=Karamlou%2C+A+H">Amir H. Karamlou</a>, <a href="/search/cond-mat?searchtype=author&query=Kechedzhi%2C+K">Kostyantyn Kechedzhi</a>, <a href="/search/cond-mat?searchtype=author&query=Berndtsson%2C+J">Julia Berndtsson</a>, <a href="/search/cond-mat?searchtype=author&query=Westerhout%2C+T">Tom Westerhout</a>, <a href="/search/cond-mat?searchtype=author&query=Asfaw%2C+A">Abraham Asfaw</a>, <a href="/search/cond-mat?searchtype=author&query=Abanin%2C+D">Dmitry Abanin</a>, <a href="/search/cond-mat?searchtype=author&query=Acharya%2C+R">Rajeev Acharya</a>, <a href="/search/cond-mat?searchtype=author&query=Beni%2C+L+A">Laleh Aghababaie Beni</a>, <a href="/search/cond-mat?searchtype=author&query=Andersen%2C+T+I">Trond I. Andersen</a>, <a href="/search/cond-mat?searchtype=author&query=Ansmann%2C+M">Markus Ansmann</a>, <a href="/search/cond-mat?searchtype=author&query=Arute%2C+F">Frank Arute</a>, <a href="/search/cond-mat?searchtype=author&query=Arya%2C+K">Kunal Arya</a>, <a href="/search/cond-mat?searchtype=author&query=Astrakhantsev%2C+N">Nikita Astrakhantsev</a>, <a href="/search/cond-mat?searchtype=author&query=Atalaya%2C+J">Juan Atalaya</a>, <a href="/search/cond-mat?searchtype=author&query=Babbush%2C+R">Ryan Babbush</a>, <a href="/search/cond-mat?searchtype=author&query=Ballard%2C+B">Brian Ballard</a>, <a href="/search/cond-mat?searchtype=author&query=Bardin%2C+J+C">Joseph C. Bardin</a>, <a href="/search/cond-mat?searchtype=author&query=Bengtsson%2C+A">Andreas Bengtsson</a>, <a href="/search/cond-mat?searchtype=author&query=Bilmes%2C+A">Alexander Bilmes</a>, <a href="/search/cond-mat?searchtype=author&query=Bortoli%2C+G">Gina Bortoli</a>, <a href="/search/cond-mat?searchtype=author&query=Bourassa%2C+A">Alexandre Bourassa</a> , et al. (195 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="2410.06557v1-abstract-short" style="display: inline;"> One of the most challenging problems in the computational study of localization in quantum manybody systems is to capture the effects of rare events, which requires sampling over exponentially many disorder realizations. We implement an efficient procedure on a quantum processor, leveraging quantum parallelism, to efficiently sample over all disorder realizations. We observe localization without d… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.06557v1-abstract-full').style.display = 'inline'; document.getElementById('2410.06557v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.06557v1-abstract-full" style="display: none;"> One of the most challenging problems in the computational study of localization in quantum manybody systems is to capture the effects of rare events, which requires sampling over exponentially many disorder realizations. We implement an efficient procedure on a quantum processor, leveraging quantum parallelism, to efficiently sample over all disorder realizations. We observe localization without disorder in quantum many-body dynamics in one and two dimensions: perturbations do not diffuse even though both the generator of evolution and the initial states are fully translationally invariant. The disorder strength as well as its density can be readily tuned using the initial state. Furthermore, we demonstrate the versatility of our platform by measuring Renyi entropies. Our method could also be extended to higher moments of the physical observables and disorder learning. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.06557v1-abstract-full').style.display = 'none'; document.getElementById('2410.06557v1-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 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2405.17385">arXiv:2405.17385</a> <span> [<a href="https://arxiv.org/pdf/2405.17385">pdf</a>, <a href="https://arxiv.org/format/2405.17385">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> </div> <p class="title is-5 mathjax"> Thermalization and Criticality on an Analog-Digital Quantum Simulator </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Andersen%2C+T+I">Trond I. Andersen</a>, <a href="/search/cond-mat?searchtype=author&query=Astrakhantsev%2C+N">Nikita Astrakhantsev</a>, <a href="/search/cond-mat?searchtype=author&query=Karamlou%2C+A+H">Amir H. Karamlou</a>, <a href="/search/cond-mat?searchtype=author&query=Berndtsson%2C+J">Julia Berndtsson</a>, <a href="/search/cond-mat?searchtype=author&query=Motruk%2C+J">Johannes Motruk</a>, <a href="/search/cond-mat?searchtype=author&query=Szasz%2C+A">Aaron Szasz</a>, <a href="/search/cond-mat?searchtype=author&query=Gross%2C+J+A">Jonathan A. Gross</a>, <a href="/search/cond-mat?searchtype=author&query=Schuckert%2C+A">Alexander Schuckert</a>, <a href="/search/cond-mat?searchtype=author&query=Westerhout%2C+T">Tom Westerhout</a>, <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+Y">Yaxing Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Forati%2C+E">Ebrahim Forati</a>, <a href="/search/cond-mat?searchtype=author&query=Rossi%2C+D">Dario Rossi</a>, <a href="/search/cond-mat?searchtype=author&query=Kobrin%2C+B">Bryce Kobrin</a>, <a href="/search/cond-mat?searchtype=author&query=Di+Paolo%2C+A">Agustin Di Paolo</a>, <a href="/search/cond-mat?searchtype=author&query=Klots%2C+A+R">Andrey R. Klots</a>, <a href="/search/cond-mat?searchtype=author&query=Drozdov%2C+I">Ilya Drozdov</a>, <a href="/search/cond-mat?searchtype=author&query=Kurilovich%2C+V+D">Vladislav D. Kurilovich</a>, <a href="/search/cond-mat?searchtype=author&query=Petukhov%2C+A">Andre Petukhov</a>, <a href="/search/cond-mat?searchtype=author&query=Ioffe%2C+L+B">Lev B. Ioffe</a>, <a href="/search/cond-mat?searchtype=author&query=Elben%2C+A">Andreas Elben</a>, <a href="/search/cond-mat?searchtype=author&query=Rath%2C+A">Aniket Rath</a>, <a href="/search/cond-mat?searchtype=author&query=Vitale%2C+V">Vittorio Vitale</a>, <a href="/search/cond-mat?searchtype=author&query=Vermersch%2C+B">Benoit Vermersch</a>, <a href="/search/cond-mat?searchtype=author&query=Acharya%2C+R">Rajeev Acharya</a>, <a href="/search/cond-mat?searchtype=author&query=Beni%2C+L+A">Laleh Aghababaie Beni</a> , et al. (202 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="2405.17385v2-abstract-short" style="display: inline;"> Understanding how interacting particles approach thermal equilibrium is a major challenge of quantum simulators. Unlocking the full potential of such systems toward this goal requires flexible initial state preparation, precise time evolution, and extensive probes for final state characterization. We present a quantum simulator comprising 69 superconducting qubits which supports both universal qua… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.17385v2-abstract-full').style.display = 'inline'; document.getElementById('2405.17385v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.17385v2-abstract-full" style="display: none;"> Understanding how interacting particles approach thermal equilibrium is a major challenge of quantum simulators. Unlocking the full potential of such systems toward this goal requires flexible initial state preparation, precise time evolution, and extensive probes for final state characterization. We present a quantum simulator comprising 69 superconducting qubits which supports both universal quantum gates and high-fidelity analog evolution, with performance beyond the reach of classical simulation in cross-entropy benchmarking experiments. Emulating a two-dimensional (2D) XY quantum magnet, we leverage a wide range of measurement techniques to study quantum states after ramps from an antiferromagnetic initial state. We observe signatures of the classical Kosterlitz-Thouless phase transition, as well as strong deviations from Kibble-Zurek scaling predictions attributed to the interplay between quantum and classical coarsening of the correlated domains. This interpretation is corroborated by injecting variable energy density into the initial state, which enables studying the effects of the eigenstate thermalization hypothesis (ETH) in targeted parts of the eigenspectrum. Finally, we digitally prepare the system in pairwise-entangled dimer states and image the transport of energy and vorticity during thermalization. These results establish the efficacy of superconducting analog-digital quantum processors for preparing states across many-body spectra and unveiling their thermalization dynamics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.17385v2-abstract-full').style.display = 'none'; document.getElementById('2405.17385v2-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 27 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/2308.11014">arXiv:2308.11014</a> <span> [<a href="https://arxiv.org/pdf/2308.11014">pdf</a>, <a href="https://arxiv.org/format/2308.11014">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> </div> <p class="title is-5 mathjax"> Stability of a quantum skyrmion: projective measurements and the quantum Zeno effect </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Salvati%2C+F">Fabio Salvati</a>, <a href="/search/cond-mat?searchtype=author&query=Katsnelson%2C+M+I">Mikhail I. Katsnelson</a>, <a href="/search/cond-mat?searchtype=author&query=Bagrov%2C+A+A">Andrey A. Bagrov</a>, <a href="/search/cond-mat?searchtype=author&query=Westerhout%2C+T">Tom Westerhout</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2308.11014v2-abstract-short" style="display: inline;"> Magnetic skyrmions are vortex-like quasiparticles characterized by long lifetime and remarkable topological properties. That makes them a promising candidate for the role of information carriers in magnetic information storage and processing devices. Although considerable progress has been made in studying skyrmions in classical systems, little is known about the quantum case: quantum skyrmions ca… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.11014v2-abstract-full').style.display = 'inline'; document.getElementById('2308.11014v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2308.11014v2-abstract-full" style="display: none;"> Magnetic skyrmions are vortex-like quasiparticles characterized by long lifetime and remarkable topological properties. That makes them a promising candidate for the role of information carriers in magnetic information storage and processing devices. Although considerable progress has been made in studying skyrmions in classical systems, little is known about the quantum case: quantum skyrmions cannot be directly observed by probing the local magnetization of the system, and the notion of topological protection is elusive in the quantum realm. Here, we explore the potential robustness of quantum skyrmions in comparison to their classical counterparts. We theoretically analyze the dynamics of a quantum skyrmion subject to local projective measurements and demonstrate that the properties of the skyrmionic quantum state change very little upon external perturbations. We further show that by performing repetitive measurements on a quantum skyrmion, it can be completely stabilized through an analog of the quantum Zeno effect. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.11014v2-abstract-full').style.display = 'none'; document.getElementById('2308.11014v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 6 September, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 21 August, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">7+eps pages, 7 figures; v2: fixed mistake in the definition of rescaled time 蟿after Eq.(6)</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2308.08590">arXiv:2308.08590</a> <span> [<a href="https://arxiv.org/pdf/2308.08590">pdf</a>, <a href="https://arxiv.org/format/2308.08590">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="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevResearch.5.043214">10.1103/PhysRevResearch.5.043214 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Understanding Symmetry Breaking in Twisted Bilayer Graphene from Cluster Constraints </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Astrakhantsev%2C+N">Nikita Astrakhantsev</a>, <a href="/search/cond-mat?searchtype=author&query=Wagner%2C+G">Glenn Wagner</a>, <a href="/search/cond-mat?searchtype=author&query=Westerhout%2C+T">Tom Westerhout</a>, <a href="/search/cond-mat?searchtype=author&query=Neupert%2C+T">Titus Neupert</a>, <a href="/search/cond-mat?searchtype=author&query=Fischer%2C+M+H">Mark H. Fischer</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2308.08590v2-abstract-short" style="display: inline;"> Twisted bilayer graphene is an exciting platform for exploring correlated quantum phases, extremely tunable with respect to both the single-particle bands and the interaction profile of electrons. Here, we investigate the phase diagram of twisted bilayer graphene as described by an extended Hubbard model on the honeycomb lattice with two fermionic orbitals (valleys) per site. Besides the special e… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.08590v2-abstract-full').style.display = 'inline'; document.getElementById('2308.08590v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2308.08590v2-abstract-full" style="display: none;"> Twisted bilayer graphene is an exciting platform for exploring correlated quantum phases, extremely tunable with respect to both the single-particle bands and the interaction profile of electrons. Here, we investigate the phase diagram of twisted bilayer graphene as described by an extended Hubbard model on the honeycomb lattice with two fermionic orbitals (valleys) per site. Besides the special extended {\it cluster interaction} $Q$, we incorporate the effect of gating through an onsite Hubbard-interaction $U$. Within Quantum Monte Carlo (QMC), we find valence-bond-solid, N茅el-valley antiferromagnetic or charge-density wave phases. Further, we elucidate the competition of these phases by noticing that the cluster interaction induces an exotic constraint on the Hilbert space, which we dub {\it the cluster rule}, in analogy to the famous pyrochlore spin-ice rule. Formulating the perturbative Hamiltonian by projecting into the cluster-rule manifold, we perform exact diagonalization and construct the fixed-point states of the observed phases. Finally, we compute the local electron density patterns as signatures distinguishing these phases, which could be observed with scanning tunneling microscopy. Our work capitalizes on the notion of cluster constraints in the extended Hubbard model of twisted bilayer graphene, and suggests a scheme towards realization of several symmetry-breaking insulating phases in a twisted-bilayer graphene sheet. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.08590v2-abstract-full').style.display = 'none'; document.getElementById('2308.08590v2-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, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 16 August, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">10 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/2207.10675">arXiv:2207.10675</a> <span> [<a href="https://arxiv.org/pdf/2207.10675">pdf</a>, <a href="https://arxiv.org/format/2207.10675">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="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Computational Physics">physics.comp-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div 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/s42005-023-01388-6">10.1038/s42005-023-01388-6 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Many-body quantum sign structures as non-glassy Ising models </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Westerhout%2C+T">Tom Westerhout</a>, <a href="/search/cond-mat?searchtype=author&query=Katsnelson%2C+M+I">Mikhail I. Katsnelson</a>, <a href="/search/cond-mat?searchtype=author&query=Bagrov%2C+A+A">Andrey A. Bagrov</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="2207.10675v2-abstract-short" style="display: inline;"> The non-trivial phase structure of the eigenstates of many-body quantum systems severely limits the applicability of quantum Monte Carlo, variational, and machine learning methods. Here, we study real-valued signful ground-state wave functions of frustrated quantum spin systems and, assuming that the tasks of finding wave function amplitudes and signs can be separated, show that the signs can be e… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.10675v2-abstract-full').style.display = 'inline'; document.getElementById('2207.10675v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2207.10675v2-abstract-full" style="display: none;"> The non-trivial phase structure of the eigenstates of many-body quantum systems severely limits the applicability of quantum Monte Carlo, variational, and machine learning methods. Here, we study real-valued signful ground-state wave functions of frustrated quantum spin systems and, assuming that the tasks of finding wave function amplitudes and signs can be separated, show that the signs can be easily bootstrapped from the amplitudes. We map the problem of finding the sign structure to an auxiliary classical Ising model defined on a subset of the Hilbert space basis. We show that the Ising model does not exhibit significant frustrations even for highly frustrated parental quantum systems, and is solvable with a fully deterministic $O(K\log K)$-time combinatorial algorithm (where $K$ is the Ising model size). Given the ground state amplitudes, we reconstruct the signs of the ground states of several frustrated quantum models, thereby revealing the hidden simplicity of many-body sign structures. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.10675v2-abstract-full').style.display = 'none'; document.getElementById('2207.10675v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 2 October, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 21 July, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2022. </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, 9 figures in the main text; 9 pages, 4 figures in the supplemental information</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Commun Phys 6, 275 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2202.12757">arXiv:2202.12757</a> <span> [<a href="https://arxiv.org/pdf/2202.12757">pdf</a>, <a href="https://arxiv.org/format/2202.12757">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> </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.106.L041104">10.1103/PhysRevB.106.L041104 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The role of correlated hopping in many-body physics of flat-band systems: Nagaoka ferromagnetism </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Westerhout%2C+T">Tom Westerhout</a>, <a href="/search/cond-mat?searchtype=author&query=Katsnelson%2C+M+I">Mikhail I. Katsnelson</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="2202.12757v3-abstract-short" style="display: inline;"> In narrow-band systems, correlated contribution to effective hopping becomes important, and one needs to carefully consider three types of hopping processes: between doubly and singly occupied sites, between singly occupied and empty sites, and between doubly occupied and empty or two singly occupied sites. All three hopping parameters cannot vanish simultaneously, and one should specify for which… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2202.12757v3-abstract-full').style.display = 'inline'; document.getElementById('2202.12757v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2202.12757v3-abstract-full" style="display: none;"> In narrow-band systems, correlated contribution to effective hopping becomes important, and one needs to carefully consider three types of hopping processes: between doubly and singly occupied sites, between singly occupied and empty sites, and between doubly occupied and empty or two singly occupied sites. All three hopping parameters cannot vanish simultaneously, and one should specify for which of these processes the band becomes flat. By means of exact diagonalization of finite systems we demonstrate that three hoppings play qualitatively different roles in many-body effects, in particular, in the formation of half-metallic ferromagnetic (Nagaoka) states. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2202.12757v3-abstract-full').style.display = 'none'; document.getElementById('2202.12757v3-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, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 25 February, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2022. </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">v3: minor corrections after acceptance for publication; v2: fix definitions of hoppings, update figures, add connection to real materials; v1: 5 pages, 1 figure in the main text, 1 figure in the supplemental information</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 106, L041104 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2107.08017">arXiv:2107.08017</a> <span> [<a href="https://arxiv.org/pdf/2107.08017">pdf</a>, <a href="https://arxiv.org/format/2107.08017">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</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/10.1088/2053-1583/ac38ca">10.1088/2053-1583/ac38ca <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Plasmonic Quantum Dots in Twisted Bilayer Graphene </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Westerhout%2C+T">Tom Westerhout</a>, <a href="/search/cond-mat?searchtype=author&query=Katsnelson%2C+M+I">Mikhail I. Katsnelson</a>, <a href="/search/cond-mat?searchtype=author&query=R%C3%B6sner%2C+M">Malte R枚sner</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="2107.08017v1-abstract-short" style="display: inline;"> We derive a material-realistic real-space many-body Hamiltonian for twisted bilayer graphene from first principles, including both single-particle hopping terms for $p_z$ electrons and long-range Coulomb interactions. By disentangling low- and high-energy subspaces of the electronic dispersion, we are able to utilize state-of-the-art constrained Random Phase Approximation calculations to reliably… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2107.08017v1-abstract-full').style.display = 'inline'; document.getElementById('2107.08017v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2107.08017v1-abstract-full" style="display: none;"> We derive a material-realistic real-space many-body Hamiltonian for twisted bilayer graphene from first principles, including both single-particle hopping terms for $p_z$ electrons and long-range Coulomb interactions. By disentangling low- and high-energy subspaces of the electronic dispersion, we are able to utilize state-of-the-art constrained Random Phase Approximation calculations to reliably describe the non-local background screening from the high-energy $s$, $p_x$, and $p_y$ electron states for arbitrary twist angles. The twist-dependent low-energy screening from $p_z$ states is subsequently added to obtain a full screening model. We use this approach to study real-space plasmonic patterns in electron-doped twisted bilayer graphene supercells and find, next to classical dipole-like modes, also twist-angle-dependent plasmonic quantum-dot-like excitations with $s$ and $p$ symmetries. Based on their inter-layer charge modulations and their footprints in the electron energy loss spectrum, we can classify these modes into "bright" and "dark" states, which show different dependencies on the twist angle. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2107.08017v1-abstract-full').style.display = 'none'; document.getElementById('2107.08017v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 July, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2021. </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, 8 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> 2D Mater. 9, 014004 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2107.03402">arXiv:2107.03402</a> <span> [<a href="https://arxiv.org/pdf/2107.03402">pdf</a>, <a href="https://arxiv.org/format/2107.03402">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Statistical Mechanics">cond-mat.stat-mech</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Disordered Systems and Neural Networks">cond-mat.dis-nn</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Machine Learning">cs.LG</span> </div> </div> <p class="title is-5 mathjax"> Self-organized criticality in neural networks </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Katsnelson%2C+M+I">Mikhail I. Katsnelson</a>, <a href="/search/cond-mat?searchtype=author&query=Vanchurin%2C+V">Vitaly Vanchurin</a>, <a href="/search/cond-mat?searchtype=author&query=Westerhout%2C+T">Tom Westerhout</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="2107.03402v1-abstract-short" style="display: inline;"> We demonstrate, both analytically and numerically, that learning dynamics of neural networks is generically attracted towards a self-organized critical state. The effect can be modeled with quartic interactions between non-trainable variables (e.g. states of neurons) and trainable variables (e.g. weight matrix). Non-trainable variables are rapidly driven towards stochastic equilibrium and trainabl… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2107.03402v1-abstract-full').style.display = 'inline'; document.getElementById('2107.03402v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2107.03402v1-abstract-full" style="display: none;"> We demonstrate, both analytically and numerically, that learning dynamics of neural networks is generically attracted towards a self-organized critical state. The effect can be modeled with quartic interactions between non-trainable variables (e.g. states of neurons) and trainable variables (e.g. weight matrix). Non-trainable variables are rapidly driven towards stochastic equilibrium and trainable variables are slowly driven towards learning equilibrium described by a scale-invariant distribution on a wide range of scales. Our results suggest that the scale invariance observed in many physical and biological systems might be due to some kind of learning dynamics and support the claim that the universe might be a neural network. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2107.03402v1-abstract-full').style.display = 'none'; document.getElementById('2107.03402v1-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 July, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">11 pages, 4 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2104.04011">arXiv:2104.04011</a> <span> [<a href="https://arxiv.org/pdf/2104.04011">pdf</a>, <a href="https://arxiv.org/format/2104.04011">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="Computational Physics">physics.comp-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/10.21105/joss.03537">10.21105/joss.03537 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> lattice-symmetries: A package for working with quantum many-body bases </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Westerhout%2C+T">Tom Westerhout</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="2104.04011v2-abstract-short" style="display: inline;"> Exact diagonalization (ED) is one of the most reliable and established numerical methods of quantum many-body theory. The main limiting factor of the method is the exponential scaling of Hilbert space dimension with system size. Fortunately, by symmetry considerations the effective dimension can be reduced by multiple orders of magnitude. Here, we present lattice-symmetries, a package for working… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2104.04011v2-abstract-full').style.display = 'inline'; document.getElementById('2104.04011v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2104.04011v2-abstract-full" style="display: none;"> Exact diagonalization (ED) is one of the most reliable and established numerical methods of quantum many-body theory. The main limiting factor of the method is the exponential scaling of Hilbert space dimension with system size. Fortunately, by symmetry considerations the effective dimension can be reduced by multiple orders of magnitude. Here, we present lattice-symmetries, a package for working with such symmetry-adapted quantum many-body bases and operators. It supports bases for spin-1/2 particles with arbitrary user-defined symmetries and generic 1-, 2-, 3-, and 4-point operators. As an example application we discuss SpinED program which allows to easily diagonalize clusters of at least 42 sites on a single node thus making large-scale ED easily accessible to people with no background in numerical methods and computational physics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2104.04011v2-abstract-full').style.display = 'none'; document.getElementById('2104.04011v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 29 September, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 8 April, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2021. </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">v2: submitted version, published in Journal of Open Source Software; extended discussion of similar software, added a note on architecture limitations, minor grammar corrections; v1: 4 pages, 1 figure</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Journal of Open Source Software, 6(64), 3537 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2101.08787">arXiv:2101.08787</a> <span> [<a href="https://arxiv.org/pdf/2101.08787">pdf</a>, <a href="https://arxiv.org/format/2101.08787">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="Disordered Systems and Neural Networks">cond-mat.dis-nn</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/PhysRevX.11.041021">10.1103/PhysRevX.11.041021 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Broken-Symmetry Ground States of the Heisenberg model on the Pyrochlore Lattice </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Astrakhantsev%2C+N">Nikita Astrakhantsev</a>, <a href="/search/cond-mat?searchtype=author&query=Westerhout%2C+T">Tom Westerhout</a>, <a href="/search/cond-mat?searchtype=author&query=Tiwari%2C+A">Apoorv Tiwari</a>, <a href="/search/cond-mat?searchtype=author&query=Choo%2C+K">Kenny Choo</a>, <a href="/search/cond-mat?searchtype=author&query=Chen%2C+A">Ao Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Fischer%2C+M+H">Mark H. Fischer</a>, <a href="/search/cond-mat?searchtype=author&query=Carleo%2C+G">Giuseppe Carleo</a>, <a href="/search/cond-mat?searchtype=author&query=Neupert%2C+T">Titus Neupert</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="2101.08787v2-abstract-short" style="display: inline;"> The spin-1/2 Heisenberg model on the pyrochlore lattice is an iconic frustrated three-dimensional spin system with a rich phase diagram. Besides hosting several ordered phases, the model is debated to possess a spin-liquid ground state when only nearest-neighbor antiferromagnetic interactions are present. Here, we contest this hypothesis with an extensive numerical investigation using both exact d… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2101.08787v2-abstract-full').style.display = 'inline'; document.getElementById('2101.08787v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2101.08787v2-abstract-full" style="display: none;"> The spin-1/2 Heisenberg model on the pyrochlore lattice is an iconic frustrated three-dimensional spin system with a rich phase diagram. Besides hosting several ordered phases, the model is debated to possess a spin-liquid ground state when only nearest-neighbor antiferromagnetic interactions are present. Here, we contest this hypothesis with an extensive numerical investigation using both exact diagonalization and complementary variational techniques. Specifically, we employ a RVB-like many-variable Monte Carlo ansatz and convolutional neural network quantum states for (variational) calculations with up to $4\times 4^3$ and $4 \times 3^3$ spins, respectively. We demonstrate that these techniques yield consistent results, allowing for reliable extrapolations to the thermodynamic limit. Our main results are (1) the determination of the phase transition between the putative spin-liquid phase and the neighboring magnetically ordered phase and (2) a careful characterization of the ground state in terms of symmetry-breaking tendencies. We find clear indications of spontaneously broken inversion and rotational symmetry, calling the scenario of a featureless quantum spin-liquid into question. Our work showcases how many-variable variational techniques can be used to make progress in answering challenging questions about three-dimensional frustrated quantum magnets. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2101.08787v2-abstract-full').style.display = 'none'; document.getElementById('2101.08787v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 November, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 21 January, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">9 pages, 5 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. X 11, 041021 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2011.02986">arXiv:2011.02986</a> <span> [<a href="https://arxiv.org/pdf/2011.02986">pdf</a>, <a href="https://arxiv.org/format/2011.02986">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="Disordered Systems and Neural Networks">cond-mat.dis-nn</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Computational Physics">physics.comp-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.104.104407">10.1103/PhysRevB.104.104407 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Kinetic samplers for neural quantum states </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Bagrov%2C+A+A">Andrey A. Bagrov</a>, <a href="/search/cond-mat?searchtype=author&query=Iliasov%2C+A+A">Askar A. Iliasov</a>, <a href="/search/cond-mat?searchtype=author&query=Westerhout%2C+T">Tom Westerhout</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="2011.02986v2-abstract-short" style="display: inline;"> Neural quantum states (NQS) are a novel class of variational many-body wave functions that are very flexible in approximating diverse quantum states. Optimization of an NQS ansatz requires sampling from the corresponding probability distribution defined by squared wave function amplitude. For this purpose we propose to use kinetic sampling protocols and demonstrate that in many important cases suc… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2011.02986v2-abstract-full').style.display = 'inline'; document.getElementById('2011.02986v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2011.02986v2-abstract-full" style="display: none;"> Neural quantum states (NQS) are a novel class of variational many-body wave functions that are very flexible in approximating diverse quantum states. Optimization of an NQS ansatz requires sampling from the corresponding probability distribution defined by squared wave function amplitude. For this purpose we propose to use kinetic sampling protocols and demonstrate that in many important cases such methods lead to much smaller autocorrelation times than Metropolis-Hastings sampling algorithm while still allowing to easily implement lattice symmetries (unlike autoregressive models). We also use Uniform Manifold Approximation and Projection algorithm to construct two-dimensional isometric embedding of Markov chains and show that kinetic sampling helps attain a more homogeneous and ergodic coverage of the Hilbert space basis. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2011.02986v2-abstract-full').style.display = 'none'; document.getElementById('2011.02986v2-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 November, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 5 November, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2020. </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">v2: 8 pages, 11 figures, UMAP analysis of typical NQS added, revtex; comments are welcome!</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 104, 104407 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1907.08186">arXiv:1907.08186</a> <span> [<a href="https://arxiv.org/pdf/1907.08186">pdf</a>, <a href="https://arxiv.org/ps/1907.08186">ps</a>, <a href="https://arxiv.org/format/1907.08186">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="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 class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41467-020-15402-w">10.1038/s41467-020-15402-w <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Neural Quantum States of frustrated magnets: generalization and sign structure </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Westerhout%2C+T">Tom Westerhout</a>, <a href="/search/cond-mat?searchtype=author&query=Astrakhantsev%2C+N">Nikita Astrakhantsev</a>, <a href="/search/cond-mat?searchtype=author&query=Tikhonov%2C+K+S">Konstantin S. Tikhonov</a>, <a href="/search/cond-mat?searchtype=author&query=Katsnelson%2C+M">Mikhail Katsnelson</a>, <a href="/search/cond-mat?searchtype=author&query=Bagrov%2C+A+A">Andrey A. Bagrov</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="1907.08186v3-abstract-short" style="display: inline;"> Neural quantum states (NQS) attract a lot of attention due to their potential to serve as a very expressive variational ansatz for quantum many-body systems. Here we study the main factors governing the applicability of NQS to frustrated magnets by training neural networks to approximate ground states of several moderately-sized Hamiltonians using the corresponding wavefunction structure on a smal… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1907.08186v3-abstract-full').style.display = 'inline'; document.getElementById('1907.08186v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1907.08186v3-abstract-full" style="display: none;"> Neural quantum states (NQS) attract a lot of attention due to their potential to serve as a very expressive variational ansatz for quantum many-body systems. Here we study the main factors governing the applicability of NQS to frustrated magnets by training neural networks to approximate ground states of several moderately-sized Hamiltonians using the corresponding wavefunction structure on a small subset of the Hilbert space basis as training dataset. We notice that generalization quality, i.e. the ability to learn from a limited number of samples and correctly approximate the target state on the rest of the space, drops abruptly when frustration is increased. We also show that learning the sign structure is considerably more difficult than learning amplitudes. Finally, we conclude that the main issue to be addressed at this stage, in order to use the method of NQS for simulating realistic models, is that of generalization rather than expressibility. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1907.08186v3-abstract-full').style.display = 'none'; document.getElementById('1907.08186v3-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 December, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 18 July, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2019. </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+6 pages, 5+7 figures, v3: added results for larger systems, improved discussion, added new references</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nat Commun 11, 1593 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1904.00031">arXiv:1904.00031</a> <span> [<a href="https://arxiv.org/pdf/1904.00031">pdf</a>, <a href="https://arxiv.org/format/1904.00031">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Disordered Systems and Neural Networks">cond-mat.dis-nn</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Computational Physics">physics.comp-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Data Analysis, Statistics and Probability">physics.data-an</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/10.1016/j.softx.2019.100311">10.1016/j.softx.2019.100311 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> NetKet: A Machine Learning Toolkit for Many-Body Quantum Systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Carleo%2C+G">Giuseppe Carleo</a>, <a href="/search/cond-mat?searchtype=author&query=Choo%2C+K">Kenny Choo</a>, <a href="/search/cond-mat?searchtype=author&query=Hofmann%2C+D">Damian Hofmann</a>, <a href="/search/cond-mat?searchtype=author&query=Smith%2C+J+E+T">James E. T. Smith</a>, <a href="/search/cond-mat?searchtype=author&query=Westerhout%2C+T">Tom Westerhout</a>, <a href="/search/cond-mat?searchtype=author&query=Alet%2C+F">Fabien Alet</a>, <a href="/search/cond-mat?searchtype=author&query=Davis%2C+E+J">Emily J. Davis</a>, <a href="/search/cond-mat?searchtype=author&query=Efthymiou%2C+S">Stavros Efthymiou</a>, <a href="/search/cond-mat?searchtype=author&query=Glasser%2C+I">Ivan Glasser</a>, <a href="/search/cond-mat?searchtype=author&query=Lin%2C+S">Sheng-Hsuan Lin</a>, <a href="/search/cond-mat?searchtype=author&query=Mauri%2C+M">Marta Mauri</a>, <a href="/search/cond-mat?searchtype=author&query=Mazzola%2C+G">Guglielmo Mazzola</a>, <a href="/search/cond-mat?searchtype=author&query=Mendl%2C+C+B">Christian B. Mendl</a>, <a href="/search/cond-mat?searchtype=author&query=van+Nieuwenburg%2C+E">Evert van Nieuwenburg</a>, <a href="/search/cond-mat?searchtype=author&query=O%27Reilly%2C+O">Ossian O'Reilly</a>, <a href="/search/cond-mat?searchtype=author&query=Th%C3%A9veniaut%2C+H">Hugo Th茅veniaut</a>, <a href="/search/cond-mat?searchtype=author&query=Torlai%2C+G">Giacomo Torlai</a>, <a href="/search/cond-mat?searchtype=author&query=Wietek%2C+A">Alexander Wietek</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="1904.00031v1-abstract-short" style="display: inline;"> We introduce NetKet, a comprehensive open source framework for the study of many-body quantum systems using machine learning techniques. The framework is built around a general and flexible implementation of neural-network quantum states, which are used as a variational ansatz for quantum wave functions. NetKet provides algorithms for several key tasks in quantum many-body physics and quantum tech… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1904.00031v1-abstract-full').style.display = 'inline'; document.getElementById('1904.00031v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1904.00031v1-abstract-full" style="display: none;"> We introduce NetKet, a comprehensive open source framework for the study of many-body quantum systems using machine learning techniques. The framework is built around a general and flexible implementation of neural-network quantum states, which are used as a variational ansatz for quantum wave functions. NetKet provides algorithms for several key tasks in quantum many-body physics and quantum technology, namely quantum state tomography, supervised learning from wave-function data, and ground state searches for a wide range of customizable lattice models. Our aim is to provide a common platform for open research and to stimulate the collaborative development of computational methods at the interface of machine learning and many-body physics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1904.00031v1-abstract-full').style.display = 'none'; document.getElementById('1904.00031v1-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 March, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> SoftwareX 10, 100311 (2019) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1801.06439">arXiv:1801.06439</a> <span> [<a href="https://arxiv.org/pdf/1801.06439">pdf</a>, <a href="https://arxiv.org/ps/1801.06439">ps</a>, <a href="https://arxiv.org/format/1801.06439">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </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.97.205434">10.1103/PhysRevB.97.205434 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Plasmon confinement in fractal quantum systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Westerhout%2C+T">Tom Westerhout</a>, <a href="/search/cond-mat?searchtype=author&query=van+Veen%2C+E">Edo van Veen</a>, <a href="/search/cond-mat?searchtype=author&query=Katsnelson%2C+M+I">Mikhail I. Katsnelson</a>, <a href="/search/cond-mat?searchtype=author&query=Yuan%2C+S">Shengjun Yuan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1801.06439v1-abstract-short" style="display: inline;"> Recent progress in the fabrication of materials has made it possible to create arbitrary non-periodic two-dimensional structures in the quantum plasmon regime. This paves the way for exploring the plasmonic properties of electron gases in complex geometries such as fractals. In this work, we study the plasmonic properties of Sierpinski carpets and gaskets, two prototypical fractals with different… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1801.06439v1-abstract-full').style.display = 'inline'; document.getElementById('1801.06439v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1801.06439v1-abstract-full" style="display: none;"> Recent progress in the fabrication of materials has made it possible to create arbitrary non-periodic two-dimensional structures in the quantum plasmon regime. This paves the way for exploring the plasmonic properties of electron gases in complex geometries such as fractals. In this work, we study the plasmonic properties of Sierpinski carpets and gaskets, two prototypical fractals with different ramification, by fully calculating their dielectric functions. We show that the Sierpinski carpet has a dispersion comparable to a square lattice, but the Sierpinski gasket features highly localized plasmon modes with a flat dispersion. This strong plasmon confinement in finitely ramified fractals can provide a novel setting for manipulating light at the quantum scale. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1801.06439v1-abstract-full').style.display = 'none'; document.getElementById('1801.06439v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 19 January, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">5 pages, 4 figures, comments are welcome</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 97, 205434 (2018) </p> </li> </ol> <div class="is-hidden-tablet">  <span class="help" style="display: inline-block;"><a href="https://github.com/arXiv/arxiv-search/releases">Search v0.5.6 released 2020-02-24</a>  </span> </div> </div> </main> <footer> <div class="columns is-desktop" role="navigation" aria-label="Secondary">  <div class="column"> <div class="columns"> <div class="column"> <ul class="nav-spaced"> <li><a href="https://info.arxiv.org/about">About</a></li> <li><a href="https://info.arxiv.org/help">Help</a></li> </ul> </div> <div class="column"> <ul class="nav-spaced"> <li> <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" class="icon filter-black" role="presentation"><title>contact arXiv</title><desc>Click here to contact arXiv</desc><path d="M502.3 190.8c3.9-3.1 9.7-.2 9.7 4.7V400c0 26.5-21.5 48-48 48H48c-26.5 0-48-21.5-48-48V195.6c0-5 5.7-7.8 9.7-4.7 22.4 17.4 52.1 39.5 154.1 113.6 21.1 15.4 56.7 47.8 92.2 47.6 35.7.3 72-32.8 92.3-47.6 102-74.1 131.6-96.3 154-113.7zM256 320c23.2.4 56.6-29.2 73.4-41.4 132.7-96.3 142.8-104.7 173.4-128.7 5.8-4.5 9.2-11.5 9.2-18.9v-19c0-26.5-21.5-48-48-48H48C21.5 64 0 85.5 0 112v19c0 7.4 3.4 14.3 9.2 18.9 30.6 23.9 40.7 32.4 173.4 128.7 16.8 12.2 50.2 41.8 73.4 41.4z"/></svg> <a href="https://info.arxiv.org/help/contact.html"> Contact</a> </li> <li> <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" class="icon filter-black" role="presentation"><title>subscribe to arXiv mailings</title><desc>Click here to subscribe</desc><path d="M476 3.2L12.5 270.6c-18.1 10.4-15.8 35.6 2.2 43.2L121 358.4l287.3-253.2c5.5-4.9 13.3 2.6 8.6 8.3L176 407v80.5c0 23.6 28.5 32.9 42.5 15.8L282 426l124.6 52.2c14.2 6 30.4-2.9 33-18.2l72-432C515 7.8 493.3-6.8 476 3.2z"/></svg> <a href="https://info.arxiv.org/help/subscribe"> Subscribe</a> </li> </ul> </div> </div> </div>   <div class="column"> <div class="columns"> <div class="column"> <ul class="nav-spaced"> <li><a href="https://info.arxiv.org/help/license/index.html">Copyright</a></li> <li><a href="https://info.arxiv.org/help/policies/privacy_policy.html">Privacy Policy</a></li> </ul> </div> <div class="column sorry-app-links"> <ul class="nav-spaced"> <li><a href="https://info.arxiv.org/help/web_accessibility.html">Web Accessibility Assistance</a></li> <li> <p class="help"> <a class="a11y-main-link" href="https://status.arxiv.org" target="_blank">arXiv Operational Status <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 256 512" class="icon filter-dark_grey" role="presentation"><path d="M224.3 273l-136 136c-9.4 9.4-24.6 9.4-33.9 0l-22.6-22.6c-9.4-9.4-9.4-24.6 0-33.9l96.4-96.4-96.4-96.4c-9.4-9.4-9.4-24.6 0-33.9L54.3 103c9.4-9.4 24.6-9.4 33.9 0l136 136c9.5 9.4 9.5 24.6.1 34z"/></svg></a><br> Get status notifications via <a class="is-link" href="https://subscribe.sorryapp.com/24846f03/email/new" target="_blank"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" class="icon filter-black" role="presentation"><path d="M502.3 190.8c3.9-3.1 9.7-.2 9.7 4.7V400c0 26.5-21.5 48-48 48H48c-26.5 0-48-21.5-48-48V195.6c0-5 5.7-7.8 9.7-4.7 22.4 17.4 52.1 39.5 154.1 113.6 21.1 15.4 56.7 47.8 92.2 47.6 35.7.3 72-32.8 92.3-47.6 102-74.1 131.6-96.3 154-113.7zM256 320c23.2.4 56.6-29.2 73.4-41.4 132.7-96.3 142.8-104.7 173.4-128.7 5.8-4.5 9.2-11.5 9.2-18.9v-19c0-26.5-21.5-48-48-48H48C21.5 64 0 85.5 0 112v19c0 7.4 3.4 14.3 9.2 18.9 30.6 23.9 40.7 32.4 173.4 128.7 16.8 12.2 50.2 41.8 73.4 41.4z"/></svg>email</a> or <a class="is-link" href="https://subscribe.sorryapp.com/24846f03/slack/new" target="_blank"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512" class="icon filter-black" role="presentation"><path d="M94.12 315.1c0 25.9-21.16 47.06-47.06 47.06S0 341 0 315.1c0-25.9 21.16-47.06 47.06-47.06h47.06v47.06zm23.72 0c0-25.9 21.16-47.06 47.06-47.06s47.06 21.16 47.06 47.06v117.84c0 25.9-21.16 47.06-47.06 47.06s-47.06-21.16-47.06-47.06V315.1zm47.06-188.98c-25.9 0-47.06-21.16-47.06-47.06S139 32 164.9 32s47.06 21.16 47.06 47.06v47.06H164.9zm0 23.72c25.9 0 47.06 21.16 47.06 47.06s-21.16 47.06-47.06 47.06H47.06C21.16 243.96 0 222.8 0 196.9s21.16-47.06 47.06-47.06H164.9zm188.98 47.06c0-25.9 21.16-47.06 47.06-47.06 25.9 0 47.06 21.16 47.06 47.06s-21.16 47.06-47.06 47.06h-47.06V196.9zm-23.72 0c0 25.9-21.16 47.06-47.06 47.06-25.9 0-47.06-21.16-47.06-47.06V79.06c0-25.9 21.16-47.06 47.06-47.06 25.9 0 47.06 21.16 47.06 47.06V196.9zM283.1 385.88c25.9 0 47.06 21.16 47.06 47.06 0 25.9-21.16 47.06-47.06 47.06-25.9 0-47.06-21.16-47.06-47.06v-47.06h47.06zm0-23.72c-25.9 0-47.06-21.16-47.06-47.06 0-25.9 21.16-47.06 47.06-47.06h117.84c25.9 0 47.06 21.16 47.06 47.06 0 25.9-21.16 47.06-47.06 47.06H283.1z"/></svg>slack</a> </p> </li> </ul> </div> </div> </div>  </div> </footer> <script src="https://static.arxiv.org/static/base/1.0.0a5/js/member_acknowledgement.js"></script> </body> </html>

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