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A resource efficient approach for quantum and classical simulations of gauge theories in particle physics

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arXiv 2020年

作者： Haase, Jan Friedrich Dellantonio, Luca Celi, Alessio Paulson, Danny Kan, Angus Jansen, Karl Muschik, Christine A. Department of Physics & Astronomy University of Waterloo WaterlooONN2L 3G1 Canada Institute for Quantum Computing University of Waterloo WaterlooONN2L 3G1 Canada Departament de Física Universitat Autònoma de Barcelona BellaterraE-08193 Spain Center for Quantum Physics Faculty of Mathematics Computer Science and Physics University of Innsbruck InnsbruckA-6020 Austria NIC DESY Platanenallee 6 ZeuthenD-15738 Germany Perimeter Institute for Theoretical Physics WaterlooONN2L 2Y5 Canada

Gauge theories establish the standard model of particle physics, and lattice gauge theory (LGT) calculations employing Markov Chain Monte Carlo (MCMC) methods have been pivotal in our understanding of fundamental interactions. The present limitations of MCMC techniques may be overcome by Hamiltonian-based simulations on classical or quantum devices, which further provide the potential to address questions that lay beyond the capabilities of the current approaches. However, for continuous gauge groups, Hamiltonian-based formulations involve infinite-dimensional gauge degrees of freedom that can solely be handled by truncation. Current truncation schemes require dramatically increasing computational resources at small values of the bare couplings, where magnetic field effects become important. Such limitation precludes one from 'taking the continuous limit' while working with finite resources. To overcome this limitation, we provide a resource-efficient protocol to simulate LGTs with continuous gauge groups in the Hamiltonian formulation. Our new method allows for calculations at arbitrary values of the bare coupling and lattice spacing. The approach consists of the combination of a Hilbert space truncation with a regularization of the gauge group, which permits an efficient description of the magnetically-dominated regime. We focus here on Abelian gauge theories and use 2+1 dimensional quantum electrodynamics as a benchmark example to demonstrate this efficient framework to achieve the continuum limit in LGTs. This possibility is a key requirement to make quantitative predictions at the field theory level and offers the long-term perspective to utilise quantum simulations to compute physically meaningful quantities in regimes that are precluded to quantum Monte Carlo. © 2020, CC BY.

关键词： Monte Carlo methods

Josephson-junction infrared single-photon detector

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arXiv 2020年

作者： Walsh, Evan D. Jung, Woochan Lee, Gil-Ho Efetov, Dmitri K. Wu, Bae-Ian Huang, K.-F. Ohki, Thomas A. Taniguchi, Takashi Watanabe, Kenji Kim, Philip Englund, Dirk Fong, Kin Chung Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology CambridgeMA02139 United States School of Engineering and Applied Sciences Harvard University CambridgeMA02138 United States Department of Physics Pohang University of Science and Technology Pohang790-784 Korea Republic of Department of Physics Harvard University CambridgeMA02138 United States 08860 Spain Air Force Research Laboratory Wright-Patterson AFB OH45433 United States Raytheon BBN Technologies Quantum Engineering and Computing Group CambridgeMA02138 United States International Center for Materials Nanoarchitectonics National Institute for Materials Science Tsukuba Japan Research Center for Functional Materials National Institute for Materials Science Tsukuba Japan

Josephson junctions (JJs) are ubiquitous superconducting devices, enabling high sensitivity magnetometers and voltage amplifiers, as well as forming the basis of high performance cryogenic computer and superconducting quantum computers. While JJ performance can be degraded by quasiparticles (QPs) formed from broken Cooper pairs, this phenomenon also opens opportunities to sensitively detect electromagnetic radiation. Here we demonstrate single near-infrared photon detection by coupling photons to the localized surface plasmons of a graphene-based JJ. Using the photon-induced switching statistics of the current-biased JJ, we reveal the critical role of QPs generated by the absorbed photon in the detection mechanism. The photon-sensitive JJ will enable a high-speed, low-power optical interconnect for future JJ-based computing architectures. Copyright © 2020, The Authors. All rights reserved.

关键词： Photons

Neural ensemble decoding for topological quantum error-correcting codes

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arXiv 2019年

作者： Sheth, Milap Jafarzadeh, Sara Zafar Gheorghiu, Vlad Institute for Quantum Computing University of Waterloo WaterlooON Canada Department of Combinatorics and Optimization University of Waterloo WaterlooON Canada David R. Cheriton School of Computer Science University of Waterloo WaterlooON Canada Department of Computer Science and Operations Research Université de Montreal MontrealQC Canada softwareQ Inc. KitchenerON Canada

Topological quantum error-correcting codes are a promising candidate for building fault-tolerant quantum computers. Decoding topological codes optimally, however, is known to be a computationally hard problem. Various decoders have been proposed that achieve approximately optimal error thresholds. Due to practical constraints, it is not known if there exists an obvious choice for a decoder. In this paper, we introduce a framework which can combine arbitrary decoders for any given code to significantly reduce the logical error rates. We rely on the crucial observation that two different decoding techniques, while possibly having similar logical error rates, can perform differently on the same error syndrome. We use machine learning techniques to assign a given error syndrome to the decoder which is likely to decode it correctly. We apply our framework to an ensemble of Minimum-Weight Perfect Matching (MWPM) and Hard-Decision Re-normalization Group (HDRG) decoders for the surface code in the depolarizing noise model. Our simulations show an improvement of 38.4%, 14.6%, and 7.1% over the pseudo-threshold of MWPM in the instance of distance 5, 7, and 9 codes, respectively. Lastly, we discuss the advantages and limitations of our framework and applicability to other error-correcting codes. Our framework can provide a significant boost to error correction by combining the strengths of various decoders. In particular, it may allow for combining very fast decoders with moderate error-correcting capability to create a very fast ensemble decoder with high error-correcting capability. Copyright © 2019, The Authors. All rights reserved.

关键词： Decoding

Does causal dynamics imply local interactions?

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arXiv 2020年

作者： Zimborás, Zoltán Farrelly, Terry Farkas, Szilárd Masanes, Lluis Wigner Research Centre for Physics BudapestH-1121 Hungary MTA-BME Lendület Quantum Information Theory Research Group Budapest Hungary Mathematical Institute Budapest University of Technology and Economics BudapestH-1111 Hungary Institut für Theoretische Physik Leibniz Universität Appelstraße 2 Hannover30167 Germany ARC Centre for Engineered Quantum Systems School of Mathematics and Physics University of Queensland BrisbaneQLD4072 Australia Computer Science Department University College London United Kingdom London Centre for Nanotechnology University College London United Kingdom

We consider quantum systems with causal dynamics in discrete spacetimes, also known as quantum cellular automata (QCA). Due to time-discreteness this type of dynamics is not characterized by a Hamiltonian but by a one-time-step unitary. This can be written as the exponential of a Hamiltonian but in a highly non-unique way. We ask if any of the Hamiltonians generating a QCA unitary is local in some sense, and we obtain two very different answers. On one hand, we present an example of QCA for which all generating Hamiltonians are fully non-local, in the sense that interactions do not decay with the distance. We expect this result to have relevant consequences for the classification of topological phases in Floquet systems, given that this relies on the effective Hamiltonian. On the other hand, we show that all one-dimensional quasi-free fermionic QCAs have quasi-local generating Hamiltonians, with interactions decaying exponentially in the massive case and algebraically in the critical case. We also prove that some integrable systems do not have local, quasi-local nor low-weight constants of motion;a result that challenges the standard definition of integrability. © 2020, CC BY.

关键词： Hamiltonians

quantum Simulation for High Energy Physics

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arXiv 2022年

作者： Bauer, Christian W. Davoudi, Zohreh Balantekin, A. Baha Bhattacharya, Tanmoy Carena, Marcela de Jong, Wibe A. Draper, Patrick El-Khadra, Aida Gemelke, Nate Hanada, Masanori Kharzeev, Dmitri Lamm, Henry Li, Ying-Ying Liu, Junyu Lukin, Mikhail Meurice, Yannick Monroe, Christopher Nachman, Benjamin Pagano, Guido Preskill, John Rinaldi, Enrico Roggero, Alessandro Santiago, David I. Savage, Martin J. Siddiqi, Irfan Siopsis, George Van Zanten, David Wiebe, Nathan Yamauchi, Yukari Yeter-Aydeniz, Kübra Zorzetti, Silvia Physics Division Lawrence Berkeley National Laboratory BerkeleyCA94720 United States Department of Physics Maryland Center for Fundamental Physics University of Maryland College ParkMD20742 United States Department of Physics University of Wisconsin MadisonWI53706 United States T-2 Los Alamos National Laboratory Los AlamosNM87545 United States Fermi National Accelerator Laboratory BataviaIL60510 United States Enrico Fermi Institute University of Chicago ChicagoIL60637 United States Kavli Institute for Cosmological Physics University of Chicago ChicagoIL60637 United States Department of Physics University of Chicago ChicagoIL60637 United States Department of Physics Illinois Center for the Advanced Study of the Universe and Illinois Quantum Information Science and Technology Center University of Illinois UrbanaIL61801 United States QuEra Computing Inc BostonMA02135 United States Department of Mathematics University of Surrey Guildford Surrey GU2 7XH United Kingdom Center for Nuclear Theory Department of Physics and Astronomy Stony Brook University NY11794-3800 United States Department of Physics Brookhaven National Laboratory UptonNY11973 United States Pritzker School of Molecular Engineering Chicago Quantum Exchange Kadanoff Center for Theoretical Physics University of Chicago IL60637 United States QBraid Co. Harper Court 5235 ChicagoIL60615 United States Department of Physics Harvard University CambridgeMA02138 United States Department of Physics and Astronomy University of Iowa Iowa CityIA52242 United States Duke Quantum Center Duke University DurhamNC27701 United States Department of Electrical and Computer Engineering Duke University DurhamNC27708 United States Department of Physics Duke University DurhamNC27708 United States IonQ Inc. College ParkMD20740 United States Physics and Astronomy Department Rice University HoustonTX77005 United States Institute for Quantum Information and Matter Californi

It is for the first time that quantum simulation for High Energy Physics (HEP) is studied in the U.S. decadal particle-physics community planning, and in fact until recently, this was not considered a mainstream topic in the community. This fact speaks of a remarkable rate of growth of this subfield over the past few years, stimulated by the impressive advancements in quantum Information sciences (QIS) and associated technologies over the past decade, and the significant investment in this area by the government and private sectors in the U.S. and other countries. High-energy physicists have quickly identified problems of importance to our understanding of nature at the most fundamental level, from tiniest distances to cosmological extents, that are intractable with classical computers but may benefit from quantum advantage. They have initiated, and continue to carry out, a vigorous program in theory, algorithm, and hardware co-design for simulations of relevance to the HEP mission. This community whitepaper is an attempt to bring this exciting and yet challenging area of research to the spotlight, and to elaborate on what the promises, requirements, challenges, and potential solutions are over the next decade and beyond. © 2022, CC BY.

关键词： High energy physics

Butterfly effect in interacting Aubry-Andre model: Thermalization, slow scrambling, and many-body localization

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arXiv 2019年

作者： Xu, Shenglong Li, Xiao Hsu, Yi-Ting Swingle, Brian Das Sarma, S. Condensed Matter Theory Center Joint Quantum Institute Department of Physics University of Maryland College ParkMD20742 United States Department of Physics City University of Hong Kong Kowloon Hong Kong Condensed Matter Theory Center Maryland Center for Fundamental Physics Joint Center for Quantum Information and Computer Science Department of Physics University of Maryland College ParkMD20742 United States

The many-body localization transition in quasiperiodic systems has been extensively studied in recent ultracold atom experiments. At intermediate quasiperiodic potential strength, a surprising Griffiths-like regime with slow dynamics appears in the absence of random disorder and mobility edges. In this work, we study the interacting Aubry-Andre model, a prototype quasiperiodic system, as a function of incommensurate potential strength using a novel dynamical measure, information scrambling, in a large system of 200 lattice sites. Between the thermal phase and the many-body localized phase, we find an intermediate dynamical phase where the butterfly velocity is zero and information spreads in space as a power-law in time. This is in contrast to the ballistic spreading in the thermal phase and logarithmic spreading in the localized phase. We further investigate the entanglement structure of the many-body eigenstates in the intermediate phase and find strong fluctuations in eigenstate entanglement entropy within a given energy window, which is inconsistent with the eigenstate thermalization hypothesis. Machine-learning on the entanglement spectrum also reaches the same conclusion. Our large-scale simulations suggest that the intermediate phase with vanishing butterfly velocity could be responsible for the slow dynamics seen in recent experiments. Copyright © 2019, The Authors. All rights reserved.

关键词： quantum entanglement

Universal Prethermal Dynamics in Gross-Neveu-Yukawa criticality

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arXiv 2019年

作者： Jian, Shao-Kai Yin, Shuai Swingle, Brian Institute for Advanced Study Tsinghua University Beijing100084 China Condensed Matter Theory Center Maryland Center for Fundamental Physics Joint Center for Quantum Information and Computer Science Department of Physics University of Maryland College ParkMD20742 United States

We study the prethermal dynamics of the Gross-Neveu-Yukawa quantum field theory, suddenly quenched in the vicinity of a quantum critical point. We find that the universal prethermal dynamics is controlled by two fixed points depending on the size of the quench. Besides the usual equilibrium chiral Ising fixed point for a shallow quench, a dynamical chiral Ising fixed point is identified for a deep quench. Intriguingly, the latter is a non-thermal fixed point without any equilibrium counterpart due to the participation of gapless fermionic fields. We also find that in the scaling regime controlled by the equilibrium fixed point, the initial slip exponent is rendered negative if there are enough flavors of fermions, thus providing a unique signature of fermionic prethermal dynamics. We then explore the temporal crossover between the universal scaling regimes governed by the two universality classes. Possible experimental realizations are also discussed. Copyright © 2019, The Authors. All rights reserved.

关键词： Dynamics

Temperature study of Rydberg exciton optical properties in Cu2O

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Physical Review B 2021年第20期103卷 205203-205203页

作者： Dongyeon Daniel Kang Aaron Gross HeeBong Yang Yusuke Morita Kyung Soo Choi Kosuke Yoshioka Na Young Kim Institute for Quantum Computing University of Waterloo 200 University Ave. West Waterloo Ontario Canada N2L 3G1 Department of Electrical and Computer Engineering University of Waterloo 200 University Ave. West Waterloo Ontario Canada N2L 3G1 Department of Physics Graduate School of Science The University of Tokyo 7-3-1 Hongo Bunkyo-ku Tokyo 113-0033 Japan Department of Physics and Astronomy University of Waterloo 200 University Ave. West Waterloo Ontario Canada N2L 3G1 Perimeter Institute for Theoretical Physics 31 Caroline St. N Waterloo Ontario Canada N2L 2Y5 Photon Science Center School of Engineering The University of Tokyo 2-11-16 Yayoi Bunkyo-ku Tokyo 113-8656 Japan Department of Chemistry University of Waterloo 200 University Ave. West Waterloo Ontario Canada N2L 3G1

Rydberg excitons in Cu2O can be an emergent platform for solid-state quantum information processing by utilizing the exaggerated properties of high-lying excited states within the material. To develop practical quantum systems, high-temperature operation is desirable. Here, we study the temperature dependence of the yellow and green Rydberg exciton resonances in a thin Cu2O crystal via broad-band phonon-assisted absorption spectra between 4 K and 100 K. At 4 K, we can identify the principal quantum number n=11 yellow and n=4 green Rydberg exciton states, beyond which we are limited by the spectral resolution of standard absorption techniques. Above liquid nitrogen boiling temperature (∼80K), the n=6 yellow and n=4 green Rydberg exciton states are readily captured and higher-temperature yellow Rydberg exciton optical properties still exhibit the standard scaling laws seen at low temperatures. This promising result lays the groundwork for a new route to build a high-temperature Rydberg quantum information processing architecture with solid-state Cu2O.

关键词： Excitons Rydberg atoms & molecules Semiconductors Optical spectroscopy Photoluminescence

Hybrid no-signaling-quantum correlations

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arXiv 2021年

作者： Banacki, Micha Mironowicz, Piotr Ramanathan, Ravishankar Horodecki, Pawe International Centre for Theory of Quantum Technologies University of Gdánsk Wita Stwosza 63 Gdańsk80-308 Poland Institute of Theoretical Physics and Astrophysics Faculty of Mathematics Physics and Informatics University of Gdánsk Wita Stwosza 57 Gdańsk80-308 Poland Department of Algorithms and System Modeling Faculty of Electronics Telecommunications and Informatics Gdánsk University of Technology Gabriela Narutowicza 11/12 Gdańsk80-233 Poland Department of Physics Stockholm University StockholmS-10691 Sweden Department of Computer Science The University of Hong Kong Pokfulam Road Hong Kong Faculty of Applied Physics and Mathematics Gdánsk University of Technology Gabriela Narutowicza 11/12 Gdańsk80-233 Poland

Fundamental investigations in non-locality have shown that while the no-signaling principle alone is not sufficient to single out the set of quantum non-local correlations, local quantum mechanics and no-signaling together exactly reproduce the set of quantum correlations in the two-party Bell scenario. Here, we introduce and study an intermediate hybrid no-signaling quantum set of non-local correlations that we term HNSQ in the multi-party Bell scenario where some subsystems are locally quantum while the remaining subsystems are only constrained by the no-signaling principle. Specifically, the set HNSQ is a super-quantum set of correlations derived from no-signaling assemblages by performing quantum measurements on the trusted subsystems. As a tool for optimization over the set HNSQ, we introduce an outer hierarchy of semi-definite programming approximations to the set following an approach put forward by Doherty-Parillo-Spedalieri. We then show that in contrast to the set NS of no-signaling correlations, there exist extreme points of HNSQ in the tripartite Bell scenario that admit quantum realization. We perform an extensive numerical analysis of the maximal violation of the facet Bell inequalities in the three-party binary input-output scenario and study the corresponding self-testing properties. In contrast to the usual no-signaling correlations, the new set allows for simple security proofs of (one-sided)-device-independent applications against super-quantum adversaries. Copyright © 2021, The Authors. All rights reserved.

关键词： Signaling