1
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Shi YH, Sun ZH, Wang YY, Wang ZA, Zhang YR, Ma WG, Liu HT, Zhao K, Song JC, Liang GH, Mei ZY, Zhang JC, Li H, Chen CT, Song X, Wang J, Xue G, Yu H, Huang K, Xiang Z, Xu K, Zheng D, Fan H. Probing spin hydrodynamics on a superconducting quantum simulator. Nat Commun 2024; 15:7573. [PMID: 39217151 PMCID: PMC11366024 DOI: 10.1038/s41467-024-52082-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Accepted: 08/23/2024] [Indexed: 09/04/2024] Open
Abstract
Characterizing the nature of hydrodynamical transport properties in quantum dynamics provides valuable insights into the fundamental understanding of exotic non-equilibrium phases of matter. Experimentally simulating infinite-temperature transport on large-scale complex quantum systems is of considerable interest. Here, using a controllable and coherent superconducting quantum simulator, we experimentally realize the analog quantum circuit, which can efficiently prepare the Haar-random states, and probe spin transport at infinite temperature. We observe diffusive spin transport during the unitary evolution of the ladder-type quantum simulator with ergodic dynamics. Moreover, we explore the transport properties of the systems subjected to strong disorder or a tilted potential, revealing signatures of anomalous subdiffusion in accompany with the breakdown of thermalization. Our work demonstrates a scalable method of probing infinite-temperature spin transport on analog quantum simulators, which paves the way to study other intriguing out-of-equilibrium phenomena from the perspective of transport.
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Affiliation(s)
- Yun-Hao Shi
- Institute of Physics, Chinese Academy of Sciences, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
- Beijing Academy of Quantum Information Sciences, Beijing, China
| | - Zheng-Hang Sun
- Institute of Physics, Chinese Academy of Sciences, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Yong-Yi Wang
- Institute of Physics, Chinese Academy of Sciences, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Zheng-An Wang
- Beijing Academy of Quantum Information Sciences, Beijing, China
- Hefei National Laboratory, Hefei, China
| | - Yu-Ran Zhang
- School of Physics and Optoelectronics, South China University of Technology, Guangzhou, China
| | - Wei-Guo Ma
- Institute of Physics, Chinese Academy of Sciences, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Hao-Tian Liu
- Institute of Physics, Chinese Academy of Sciences, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Kui Zhao
- Beijing Academy of Quantum Information Sciences, Beijing, China
| | - Jia-Cheng Song
- Institute of Physics, Chinese Academy of Sciences, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Gui-Han Liang
- Institute of Physics, Chinese Academy of Sciences, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Zheng-Yang Mei
- Institute of Physics, Chinese Academy of Sciences, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Jia-Chi Zhang
- Institute of Physics, Chinese Academy of Sciences, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Hao Li
- Beijing Academy of Quantum Information Sciences, Beijing, China
| | - Chi-Tong Chen
- Institute of Physics, Chinese Academy of Sciences, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Xiaohui Song
- Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Jieci Wang
- Department of Physics and Key Laboratory of Low Dimensional Quantum Structures and Quantum Control of Ministry of Education, Hunan Normal University, Changsha, China
| | - Guangming Xue
- Beijing Academy of Quantum Information Sciences, Beijing, China
| | - Haifeng Yu
- Beijing Academy of Quantum Information Sciences, Beijing, China
| | - Kaixuan Huang
- Beijing Academy of Quantum Information Sciences, Beijing, China.
| | - Zhongcheng Xiang
- Institute of Physics, Chinese Academy of Sciences, Beijing, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China.
- Hefei National Laboratory, Hefei, China.
| | - Kai Xu
- Institute of Physics, Chinese Academy of Sciences, Beijing, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China.
- Beijing Academy of Quantum Information Sciences, Beijing, China.
- Hefei National Laboratory, Hefei, China.
- Songshan Lake Materials Laboratory, Dongguan, China.
- CAS Center for Excellence in Topological Quantum Computation, UCAS, Beijing, China.
| | - Dongning Zheng
- Institute of Physics, Chinese Academy of Sciences, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
- Hefei National Laboratory, Hefei, China
- Songshan Lake Materials Laboratory, Dongguan, China
- CAS Center for Excellence in Topological Quantum Computation, UCAS, Beijing, China
| | - Heng Fan
- Institute of Physics, Chinese Academy of Sciences, Beijing, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China.
- Beijing Academy of Quantum Information Sciences, Beijing, China.
- Hefei National Laboratory, Hefei, China.
- Songshan Lake Materials Laboratory, Dongguan, China.
- CAS Center for Excellence in Topological Quantum Computation, UCAS, Beijing, China.
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2
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Hakoshima H, Endo S, Yamamoto K, Matsuzaki Y, Yoshioka N. Localized Virtual Purification. PHYSICAL REVIEW LETTERS 2024; 133:080601. [PMID: 39241702 DOI: 10.1103/physrevlett.133.080601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 04/08/2024] [Accepted: 06/18/2024] [Indexed: 09/09/2024]
Abstract
Analog and digital quantum simulators can efficiently simulate quantum many-body systems that appear in natural phenomena. However, experimental limitations of near-term devices still make it challenging to perform the entire process of quantum simulation. The purification-based quantum simulation methods can alleviate the limitations in experiments such as the cooling temperature and noise from the environment, while this method has the drawback that it requires global entangled measurement with a prohibitively large number of measurements that scales exponentially with the system size. In this Letter, we propose that we can overcome these problems by restricting the entangled measurements to the vicinity of the local observables to be measured, when the locality of the system can be exploited. We provide theoretical guarantees that the global purification operation can be replaced with local operations under some conditions, in particular for the task of cooling and error mitigation. We furthermore give a numerical verification that the localized purification is valid even when conditions are not satisfied. Our method bridges the fundamental concept of locality with quantum simulators, and therefore is expected to open a path to unexplored quantum many-body phenomena.
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Affiliation(s)
- Hideaki Hakoshima
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
- Center for Quantum Information and Quantum Biology, Osaka University, 1-2 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | | | | | - Yuichiro Matsuzaki
- Department of Electrical, Electronic, and Communication Engineering, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan
| | - Nobuyuki Yoshioka
- JST, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
- Department of Applied Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research (CPR), Wako-shi, Saitama 351-0198, Japan
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3
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Impertro A, Karch S, Wienand JF, Huh S, Schweizer C, Bloch I, Aidelsburger M. Local Readout and Control of Current and Kinetic Energy Operators in Optical Lattices. PHYSICAL REVIEW LETTERS 2024; 133:063401. [PMID: 39178442 DOI: 10.1103/physrevlett.133.063401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 05/17/2024] [Accepted: 06/06/2024] [Indexed: 08/25/2024]
Abstract
Quantum gas microscopes have revolutionized quantum simulations with ultracold atoms, allowing one to measure local observables and snapshots of quantum states. However, measurements so far were mostly carried out in the occupation basis. Here, we demonstrate how all kinetic operators, such as kinetic energy or current operators, can be measured and manipulated with single-bond resolution. Beyond simple expectation values of these observables, the single-shot measurements allow one to access full counting statistics and complex correlation functions. Our work paves the way for the implementation of efficient quantum state tomography and hybrid quantum computing protocols for itinerant particles on a lattice. In addition, we demonstrate how site-resolved programmable potentials enable a spatially selective, parallel readout in different bases as well as the engineering of arbitrary initial states.
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4
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Pavlov VP, Chorbadzhiyska YR, Nation C, Porras D, Ivanov PA. Random matrix theory approach to quantum Fisher information in quantum ergodic systems. Phys Rev E 2024; 110:024135. [PMID: 39294957 DOI: 10.1103/physreve.110.024135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 08/07/2024] [Indexed: 09/21/2024]
Abstract
We theoretically investigate quantum parameter estimation in quantum chaotic systems. Our analysis is based on an effective description of quantum ergodic systems in terms of a random matrix Hamiltonian. Based on this approach, we derive an analytical expression for the time evolution of the quantum Fisher information (QFI), which we find to have three distinct timescales. Initially, the QFI increase is quadratic in time, characterizing the timescale over which initial information is extractable from local measurements only. This quickly passes into linear increase with slope determined by the decay rate of the measured spin observable. When the information is fully spread among all degrees of freedom, a second quadratic timescale determines the long-time behavior of the QFI. We test our random matrix theory prediction with the exact diagonalization of a nonintegrable spin system, focusing on the estimation of a local magnetic field by measurements of the many-body state. Our numerical calculations agree with the effective random matrix theory approach and show that the information on the local Hamiltonian parameter is distributed throughout the quantum system during the quantum thermalization process.
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5
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Huang Y, Qiu Y, Young RM, Schatz GC, Krzyaniak MD, Wasielewski MR. Identifying Sources of Entanglement Loss in Photodriven Molecular Electron Spin Teleportation. J Am Chem Soc 2024; 146:20133-20140. [PMID: 38995837 DOI: 10.1021/jacs.4c04393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/14/2024]
Abstract
We report on an electron donor-electron acceptor-stable radical (D-A-R•) molecule in which an electron spin state first prepared on R• is followed by photogeneration of an entangled singlet 1[D•+-A•-] spin pair to produce D•+-A•--R•. Since the A•- and R• spins within D•+-A•--R• are uncorrelated, spin teleportation from R• to D•+ occurs with a maximal 25% efficiency only for the singlet pair 1(A•--R•) by spin-allowed electron transfer from A•- to R•. However, since 1[D•+-A•-] is sufficiently long-lived, coherent spin mixing involving the unreactive 3(A•--R•) population affects entanglement and teleportation within D•+-A•--R•. Pulse electron paramagnetic resonance experiments show a direct correlation between electron spin flip-flops and entanglement loss, providing information for designing molecular materials to serve as nanoscale quantum device interconnects.
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6
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Yao Y, Xiang L. Superconducting Quantum Simulation for Many-Body Physics beyond Equilibrium. ENTROPY (BASEL, SWITZERLAND) 2024; 26:592. [PMID: 39056954 PMCID: PMC11275873 DOI: 10.3390/e26070592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2024] [Revised: 07/07/2024] [Accepted: 07/09/2024] [Indexed: 07/28/2024]
Abstract
Quantum computing is an exciting field that uses quantum principles, such as quantum superposition and entanglement, to tackle complex computational problems. Superconducting quantum circuits, based on Josephson junctions, is one of the most promising physical realizations to achieve the long-term goal of building fault-tolerant quantum computers. The past decade has witnessed the rapid development of this field, where many intermediate-scale multi-qubit experiments emerged to simulate nonequilibrium quantum many-body dynamics that are challenging for classical computers. Here, we review the basic concepts of superconducting quantum simulation and their recent experimental progress in exploring exotic nonequilibrium quantum phenomena emerging in strongly interacting many-body systems, e.g., many-body localization, quantum many-body scars, and discrete time crystals. We further discuss the prospects of quantum simulation experiments to truly solve open problems in nonequilibrium many-body systems.
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Affiliation(s)
- Yunyan Yao
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, Department of Physics, Zhejiang University, Hangzhou 311200, China
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7
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Joshi LK, Franke J, Rath A, Ares F, Murciano S, Kranzl F, Blatt R, Zoller P, Vermersch B, Calabrese P, Roos CF, Joshi MK. Observing the Quantum Mpemba Effect in Quantum Simulations. PHYSICAL REVIEW LETTERS 2024; 133:010402. [PMID: 39042798 DOI: 10.1103/physrevlett.133.010402] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 03/29/2024] [Indexed: 07/25/2024]
Abstract
The nonequilibrium physics of many-body quantum systems harbors various unconventional phenomena. In this Letter, we experimentally investigate one of the most puzzling of these phenomena-the quantum Mpemba effect, where a tilted ferromagnet restores its symmetry more rapidly when it is farther from the symmetric state compared to when it is closer. We present the first experimental evidence of the occurrence of this effect in a trapped-ion quantum simulator. The symmetry breaking and restoration are monitored through entanglement asymmetry, probed via randomized measurements, and postprocessed using the classical shadows technique. Our findings are further substantiated by measuring the Frobenius distance between the experimental state and the stationary thermal symmetric theoretical state, offering direct evidence of subsystem thermalization.
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Affiliation(s)
- Lata Kh Joshi
- Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, Technikerstraße 21a, 6020 Innsbruck, Austria
- University of Innsbruck, Institute for Theoretical Physics, Technikerstraße 21a, 6020 Innsbruck, Austria
- SISSA and INFN, via Bonomea 265, 34136 Trieste, Italy
| | - Johannes Franke
- Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, Technikerstraße 21a, 6020 Innsbruck, Austria
- University of Innsbruck, Institute for Experimental Physics, Technikerstraße 25, 6020 Innsbruck, Austria
| | - Aniket Rath
- Univiversité Grenoble Alpes, CNRS, LPMMC, 38000 Grenoble, France
| | | | - Sara Murciano
- Walter Burke Institute for Theoretical Physics, and Department of Physics and IQIM, Caltech, Pasadena, California 91125, USA
| | - Florian Kranzl
- Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, Technikerstraße 21a, 6020 Innsbruck, Austria
- University of Innsbruck, Institute for Experimental Physics, Technikerstraße 25, 6020 Innsbruck, Austria
| | - Rainer Blatt
- Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, Technikerstraße 21a, 6020 Innsbruck, Austria
- University of Innsbruck, Institute for Experimental Physics, Technikerstraße 25, 6020 Innsbruck, Austria
| | - Peter Zoller
- Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, Technikerstraße 21a, 6020 Innsbruck, Austria
- University of Innsbruck, Institute for Theoretical Physics, Technikerstraße 21a, 6020 Innsbruck, Austria
| | - Benoît Vermersch
- Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, Technikerstraße 21a, 6020 Innsbruck, Austria
- University of Innsbruck, Institute for Theoretical Physics, Technikerstraße 21a, 6020 Innsbruck, Austria
- Univiversité Grenoble Alpes, CNRS, LPMMC, 38000 Grenoble, France
| | - Pasquale Calabrese
- SISSA and INFN, via Bonomea 265, 34136 Trieste, Italy
- International Centre for Theoretical Physics (ICTP), Strada Costiera 11, 34151 Trieste, Italy
| | - Christian F Roos
- Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, Technikerstraße 21a, 6020 Innsbruck, Austria
- University of Innsbruck, Institute for Experimental Physics, Technikerstraße 25, 6020 Innsbruck, Austria
| | - Manoj K Joshi
- Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, Technikerstraße 21a, 6020 Innsbruck, Austria
- University of Innsbruck, Institute for Experimental Physics, Technikerstraße 25, 6020 Innsbruck, Austria
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8
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Burke PC, Nakerst G, Haque M. Structure of the Hamiltonian of mean force. Phys Rev E 2024; 110:014111. [PMID: 39160947 DOI: 10.1103/physreve.110.014111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 06/06/2024] [Indexed: 08/21/2024]
Abstract
The Hamiltonian of mean force is an effective Hamiltonian that allows a quantum system, nonweakly coupled to an environment, to be written in an effective Gibbs state. We present results on the structure of the Hamiltonian of mean force in extended quantum systems with local interactions. We show that its spatial structure exhibits a "skin effect"-its difference from the system Hamiltonian dies off exponentially with distance from the system-environment boundary. For spin systems, we identify the terms that can appear in the Hamiltonian of mean force at different orders in the inverse temperature.
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Affiliation(s)
- Phillip C Burke
- School of Physics, University College Dublin, Belfield, Dublin 4, Ireland
- Centre for Quantum Engineering, Science, and Technology, University College Dublin, Dublin 4, Ireland
- Department of Theoretical Physics, Maynooth University, Maynooth, Kildare, W23 F2H6, Ireland
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9
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Brenes M, Min B, Anto-Sztrikacs N, Bar-Gill N, Segal D. Bath-induced interactions and transient dynamics in open quantum systems at strong coupling: Effective Hamiltonian approach. J Chem Phys 2024; 160:244106. [PMID: 38916270 DOI: 10.1063/5.0207028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Accepted: 06/05/2024] [Indexed: 06/26/2024] Open
Abstract
Understanding the dynamics of dissipative quantum systems, particularly beyond the weak coupling approximation, is central to various quantum applications. While numerically exact methods provide accurate solutions, they often lack the analytical insight provided by theoretical approaches. In this study, we employ the recently developed method dubbed the effective Hamiltonian theory to understand the dynamics of system-bath configurations without resorting to a perturbative description of the system-bath coupling energy. Through a combination of mapping steps and truncation, the effective Hamiltonian theory offers both analytical insights into signatures of strong couplings in open quantum systems and a straightforward path for numerical simulations. To validate the accuracy of the method, we apply it to two canonical models: a single spin immersed in a bosonic bath and two noninteracting spins in a common bath. In both cases, we study the transient regime and the steady state limit at nonzero temperature and spanning system-bath interactions from the weak to the strong regime. By comparing the results of the effective Hamiltonian theory with numerically exact simulations, we show that although the former overlooks non-Markovian features in the transient equilibration dynamics, it correctly captures non-perturbative bath-generated couplings between otherwise non-interacting spins, as observed in their synchronization dynamics and correlations. Altogether, the effective Hamiltonian theory offers a powerful approach for understanding strong coupling dynamics and thermodynamics, capturing the signatures of such interactions in both relaxation dynamics and in the steady state limit.
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Affiliation(s)
- Marlon Brenes
- Department of Physics and Centre for Quantum Information and Quantum Control, University of Toronto, 60 Saint George St., Toronto, Ontario M5S 1A7, Canada
| | - Brett Min
- Department of Physics and Centre for Quantum Information and Quantum Control, University of Toronto, 60 Saint George St., Toronto, Ontario M5S 1A7, Canada
| | - Nicholas Anto-Sztrikacs
- Department of Physics and Centre for Quantum Information and Quantum Control, University of Toronto, 60 Saint George St., Toronto, Ontario M5S 1A7, Canada
| | - Nir Bar-Gill
- Department of Applied Physics, The Hebrew University of Jerusalem, Jerusalem, Israel
- The Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Dvira Segal
- Department of Physics and Centre for Quantum Information and Quantum Control, University of Toronto, 60 Saint George St., Toronto, Ontario M5S 1A7, Canada
- Department of Chemistry, University of Toronto, 80 Saint George St., Toronto, Ontario M5S 3H6, Canada
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10
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Liu Y, He D. Chaotic route to classical thermalization: A real-space analysis. Phys Rev E 2024; 109:064115. [PMID: 39020962 DOI: 10.1103/physreve.109.064115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Accepted: 05/23/2024] [Indexed: 07/20/2024]
Abstract
Most of the previous studies on classical thermalization focus on the wave-vector space, encountering limitations when extended beyond quasi-integrable regions. In this study, we propose a scheme to study the thermalization of the classical Hamiltonian chain of interacting oscillators in real space by developing a thermalization indicator proposed by Parisi [Europhys. Lett. 40, 357 (1997)0295-507510.1209/epl/i1997-00471-9], which approaches zero in the thermal state. Upon reaching the steady state characterized by the generalized Gibbs ensemble for a harmonic chain, a quench protocol is implemented to change the Hamiltonian to a nonintegrable form instantaneously, thereby preparing nonequilibrium initial states. This approach enables investigations of thermalization in real space, particularly valuable for exploring regions beyond quasi-integrability. For the FPUT-β lattice, we observe that the thermalization time as a function of the nonintegrable strength follows a -2 scaling law in the quasi-integrable region and -1/4 in the strongly integrable region. Moreover, numerical results reveal the thermalization time is proportional to the Lyapunov time, which bridges microscopic chaotic dynamics and the macroscopic thermalization process.
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11
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Wu Z, Wang P, Wang T, Li Y, Liu R, Chen Y, Peng X, Liu RB. Selective Detection of Dynamics-Complete Set of Correlations via Quantum Channels. PHYSICAL REVIEW LETTERS 2024; 132:200802. [PMID: 38829065 DOI: 10.1103/physrevlett.132.200802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 02/25/2024] [Accepted: 04/01/2024] [Indexed: 06/05/2024]
Abstract
Correlations of fluctuations are essential to understanding many-body systems and key information for advancing quantum technologies. To fully describe the dynamics of a physical system, all time-ordered correlations (TOCs), i.e., the dynamics-complete set of correlations are needed. The current measurement techniques can only access a limited set of TOCs, and there has been no systematic and feasible solution for extracting the dynamic-complete set of correlations hitherto. Here we propose a platform-universal protocol to selectively detect arbitrary types of TOCs via quantum channels. In our method, the quantum channels are synthesized with various controls, and engineer the evolution of a sensor-target system along a specific path that corresponds to a desired correlation. Using nuclear magnetic resonance, we experimentally demonstrate this protocol by detecting a specific type of fourth-order TOC that has never been accessed previously. We also show that the knowledge of the TOCs can be used to significantly improve the precision of quantum optimal control. Our method provides a new toolbox for characterizing the quantum many-body states and quantum noise, and hence for advancing the fields of quantum sensing and quantum computing.
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Affiliation(s)
- Ze Wu
- CAS Key Laboratory of Microscale Magnetic Resonance and School of Physical Sciences, University of Science and Technology of China, Hefei 230026, China
- CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Ping Wang
- Faculty of Arts and Sciences, Beijing Normal University, Zhuhai 519087, China
- Department of Physics, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Tianyun Wang
- CAS Key Laboratory of Microscale Magnetic Resonance and School of Physical Sciences, University of Science and Technology of China, Hefei 230026, China
- CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Yuchen Li
- CAS Key Laboratory of Microscale Magnetic Resonance and School of Physical Sciences, University of Science and Technology of China, Hefei 230026, China
- CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Ran Liu
- CAS Key Laboratory of Microscale Magnetic Resonance and School of Physical Sciences, University of Science and Technology of China, Hefei 230026, China
- CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Yuquan Chen
- CAS Key Laboratory of Microscale Magnetic Resonance and School of Physical Sciences, University of Science and Technology of China, Hefei 230026, China
- CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Xinhua Peng
- CAS Key Laboratory of Microscale Magnetic Resonance and School of Physical Sciences, University of Science and Technology of China, Hefei 230026, China
- CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
| | - Ren-Bao Liu
- Department of Physics, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
- Centre for Quantum Coherence, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
- The Hong Kong Institute of Quantum Information Science and Technology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
- New Cornerstone Science Laboratory, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
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12
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Huang Z, Guo XK. Subsystem eigenstate thermalization hypothesis for translation invariant systems. Phys Rev E 2024; 109:054120. [PMID: 38907484 DOI: 10.1103/physreve.109.054120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 04/26/2024] [Indexed: 06/24/2024]
Abstract
The eigenstate thermalization hypothesis for translation invariant quantum spin systems has been proved recently by using random matrices. In this paper, we study the subsystem version of the eigenstate thermalization hypothesis for translation invariant quantum systems without referring to random matrices. We first find a relation between the quantum variance and the Belavkin-Staszewski relative entropy. Then, by showing the small upper bounds on the quantum variance and the Belavkin-Staszewski relative entropy, we prove the subsystem eigenstate thermalization hypothesis for translation invariant quantum systems with an algebraic speed of convergence in an elementary way. The proof holds for most of the translation invariant quantum lattice models with exponential or algebraic decays of correlations.
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Affiliation(s)
- Zhiqiang Huang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
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13
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Young AW, Geller S, Eckner WJ, Schine N, Glancy S, Knill E, Kaufman AM. An atomic boson sampler. Nature 2024; 629:311-316. [PMID: 38720040 DOI: 10.1038/s41586-024-07304-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 03/13/2024] [Indexed: 05/12/2024]
Abstract
A boson sampler implements a restricted model of quantum computing. It is defined by the ability to sample from the distribution resulting from the interference of identical bosons propagating according to programmable, non-interacting dynamics1. An efficient exact classical simulation of boson sampling is not believed to exist, which has motivated ground-breaking boson sampling experiments in photonics with increasingly many photons2-12. However, it is difficult to generate and reliably evolve specific numbers of photons with low loss, and thus probabilistic techniques for postselection7 or marked changes to standard boson sampling10-12 are generally used. Here, we address the above challenges by implementing boson sampling using ultracold atoms13,14 in a two-dimensional, tunnel-coupled optical lattice. This demonstration is enabled by a previously unrealized combination of tools involving high-fidelity optical cooling and imaging of atoms in a lattice, as well as programmable control of those atoms using optical tweezers. When extended to interacting systems, our work demonstrates the core abilities required to directly assemble ground and excited states in simulations of various Hubbard models15,16.
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Affiliation(s)
- Aaron W Young
- JILA, University of Colorado and National Institute of Standards and Technology and Department of Physics, University of Colorado, Boulder, CO, USA.
| | - Shawn Geller
- National Institute of Standards and Technology, Boulder, CO, USA
- Department of Physics, University of Colorado, Boulder, CO, USA
| | - William J Eckner
- JILA, University of Colorado and National Institute of Standards and Technology and Department of Physics, University of Colorado, Boulder, CO, USA
| | - Nathan Schine
- JILA, University of Colorado and National Institute of Standards and Technology and Department of Physics, University of Colorado, Boulder, CO, USA
- Joint Quantum Institute, University of Maryland Department of Physics and National Institute of Standards and Technology, College Park, MD, USA
| | - Scott Glancy
- National Institute of Standards and Technology, Boulder, CO, USA
| | - Emanuel Knill
- National Institute of Standards and Technology, Boulder, CO, USA
- Center for Theory of Quantum Matter, University of Colorado, Boulder, CO, USA
| | - Adam M Kaufman
- JILA, University of Colorado and National Institute of Standards and Technology and Department of Physics, University of Colorado, Boulder, CO, USA.
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14
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Karamlou AH, Rosen IT, Muschinske SE, Barrett CN, Di Paolo A, Ding L, Harrington PM, Hays M, Das R, Kim DK, Niedzielski BM, Schuldt M, Serniak K, Schwartz ME, Yoder JL, Gustavsson S, Yanay Y, Grover JA, Oliver WD. Probing entanglement in a 2D hard-core Bose-Hubbard lattice. Nature 2024; 629:561-566. [PMID: 38658761 PMCID: PMC11096108 DOI: 10.1038/s41586-024-07325-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 03/15/2024] [Indexed: 04/26/2024]
Abstract
Entanglement and its propagation are central to understanding many physical properties of quantum systems1-3. Notably, within closed quantum many-body systems, entanglement is believed to yield emergent thermodynamic behaviour4-7. However, a universal understanding remains challenging owing to the non-integrability and computational intractability of most large-scale quantum systems. Quantum hardware platforms provide a means to study the formation and scaling of entanglement in interacting many-body systems8-14. Here we use a controllable 4 × 4 array of superconducting qubits to emulate a 2D hard-core Bose-Hubbard (HCBH) lattice. We generate superposition states by simultaneously driving all lattice sites and extract correlation lengths and entanglement entropy across its many-body energy spectrum. We observe volume-law entanglement scaling for states at the centre of the spectrum and a crossover to the onset of area-law scaling near its edges.
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Affiliation(s)
- Amir H Karamlou
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Google Quantum AI, Santa Barbara, CA, USA.
| | - Ilan T Rosen
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Sarah E Muschinske
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Cora N Barrett
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Physics, Wellesley College, Wellesley, MA, USA
| | - Agustin Di Paolo
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Leon Ding
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Patrick M Harrington
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Max Hays
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | | | | | | | | | - Kyle Serniak
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
- MIT Lincoln Laboratory, Lexington, MA, USA
| | | | | | - Simon Gustavsson
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Yariv Yanay
- Laboratory for Physical Sciences, College Park, MD, USA
| | - Jeffrey A Grover
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - William D Oliver
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA.
- MIT Lincoln Laboratory, Lexington, MA, USA.
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15
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Fabritius P, Mohan J, Talebi M, Wili S, Zwerger W, Huang MZ, Esslinger T. Irreversible entropy transport enhanced by fermionic superfluidity. NATURE PHYSICS 2024; 20:1091-1096. [PMID: 39036649 PMCID: PMC11254751 DOI: 10.1038/s41567-024-02483-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 03/20/2024] [Indexed: 07/23/2024]
Abstract
The nature of particle and entropy flow between two superfluids is often understood in terms of reversible flow carried by an entropy-free, macroscopic wavefunction. While this wavefunction is responsible for many intriguing properties of superfluids and superconductors, its interplay with excitations in non-equilibrium situations is less understood. Here we observe large concurrent flows of both particles and entropy through a ballistic channel connecting two strongly interacting fermionic superfluids. Both currents respond nonlinearly to chemical potential and temperature biases. We find that the entropy transported per particle is much larger than the prediction of superfluid hydrodynamics in the linear regime and largely independent of changes in the channel's geometry. By contrast, the timescales of advective and diffusive entropy transport vary significantly with the channel geometry. In our setting, superfluidity counterintuitively increases the speed of entropy transport. Moreover, we develop a phenomenological model describing the nonlinear dynamics within the framework of generalized gradient dynamics. Our approach for measuring entropy currents may help elucidate mechanisms of heat transfer in superfluids and superconducting devices.
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Affiliation(s)
- Philipp Fabritius
- Institute for Quantum Electronics & Quantum Center, ETH Zurich, Zurich, Switzerland
| | - Jeffrey Mohan
- Institute for Quantum Electronics & Quantum Center, ETH Zurich, Zurich, Switzerland
| | - Mohsen Talebi
- Institute for Quantum Electronics & Quantum Center, ETH Zurich, Zurich, Switzerland
| | - Simon Wili
- Institute for Quantum Electronics & Quantum Center, ETH Zurich, Zurich, Switzerland
| | - Wilhelm Zwerger
- Physik Department, Technische Universität München, Garching, Germany
| | - Meng-Zi Huang
- Institute for Quantum Electronics & Quantum Center, ETH Zurich, Zurich, Switzerland
| | - Tilman Esslinger
- Institute for Quantum Electronics & Quantum Center, ETH Zurich, Zurich, Switzerland
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16
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Shaw AL, Chen Z, Choi J, Mark DK, Scholl P, Finkelstein R, Elben A, Choi S, Endres M. Benchmarking highly entangled states on a 60-atom analogue quantum simulator. Nature 2024; 628:71-77. [PMID: 38509372 PMCID: PMC10990925 DOI: 10.1038/s41586-024-07173-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 02/07/2024] [Indexed: 03/22/2024]
Abstract
Quantum systems have entered a competitive regime in which classical computers must make approximations to represent highly entangled quantum states1,2. However, in this beyond-classically-exact regime, fidelity comparisons between quantum and classical systems have so far been limited to digital quantum devices2-5, and it remains unsolved how to estimate the actual entanglement content of experiments6. Here, we perform fidelity benchmarking and mixed-state entanglement estimation with a 60-atom analogue Rydberg quantum simulator, reaching a high-entanglement entropy regime in which exact classical simulation becomes impractical. Our benchmarking protocol involves extrapolation from comparisons against an approximate classical algorithm, introduced here, with varying entanglement limits. We then develop and demonstrate an estimator of the experimental mixed-state entanglement6, finding our experiment is competitive with state-of-the-art digital quantum devices performing random circuit evolution2-5. Finally, we compare the experimental fidelity against that achieved by various approximate classical algorithms, and find that only the algorithm we introduce is able to keep pace with the experiment on the classical hardware we use. Our results enable a new model for evaluating the ability of both analogue and digital quantum devices to generate entanglement in the beyond-classically-exact regime, and highlight the evolving divide between quantum and classical systems.
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Affiliation(s)
- Adam L Shaw
- California Institute of Technology, Pasadena, CA, USA.
| | - Zhuo Chen
- Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
- The NSF AI Institute for Artificial Intelligence and Fundamental Interactions, Cambridge, MA, USA
| | - Joonhee Choi
- California Institute of Technology, Pasadena, CA, USA
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Daniel K Mark
- Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Pascal Scholl
- California Institute of Technology, Pasadena, CA, USA
| | | | - Andreas Elben
- California Institute of Technology, Pasadena, CA, USA
| | - Soonwon Choi
- Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, MA, USA.
| | - Manuel Endres
- California Institute of Technology, Pasadena, CA, USA.
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17
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Lee S, Kwon H, Lee JS. Estimating entanglement entropy via variational quantum circuits with classical neural networks. Phys Rev E 2024; 109:044117. [PMID: 38755883 DOI: 10.1103/physreve.109.044117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 02/22/2024] [Indexed: 05/18/2024]
Abstract
Entropy plays a crucial role in both physics and information science, encompassing classical and quantum domains. In this paper, we present the quantum neural entropy estimator (QNEE), an approach that combines classical neural network (NN) with variational quantum circuits to estimate the von Neumann and Rényi entropies of a quantum state. QNEE provides accurate estimates of entropy while also yielding the eigenvalues and eigenstates of the input density matrix. Leveraging the capabilities of classical NN, QNEE can classify different phases of quantum systems that accompany the changes of entanglement entropy. Our numerical simulation demonstrates the effectiveness of QNEE by applying it to the 1D XXZ Heisenberg model. In particular, QNEE exhibits high sensitivity in estimating entanglement entropy near the phase transition point. We expect that QNEE will serve as a valuable tool for quantum entropy estimation and phase classification.
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Affiliation(s)
- Sangyun Lee
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, USA
- School of Physics, Korea Institute for Advanced Study, Seoul, 02455, Korea
| | - Hyukjoon Kwon
- School of Computational Sciences, Korea Institute for Advanced Study, Seoul 02455, Korea
| | - Jae Sung Lee
- School of Physics, Korea Institute for Advanced Study, Seoul, 02455, Korea
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18
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Mi X, Michailidis AA, Shabani S, Miao KC, Klimov PV, Lloyd J, Rosenberg E, Acharya R, Aleiner I, Andersen TI, Ansmann M, Arute F, Arya K, Asfaw A, Atalaya J, Bardin JC, Bengtsson A, Bortoli G, Bourassa A, Bovaird J, Brill L, Broughton M, Buckley BB, Buell DA, Burger T, Burkett B, Bushnell N, Chen Z, Chiaro B, Chik D, Chou C, Cogan J, Collins R, Conner P, Courtney W, Crook AL, Curtin B, Dau AG, Debroy DM, Del Toro Barba A, Demura S, Di Paolo A, Drozdov IK, Dunsworth A, Erickson C, Faoro L, Farhi E, Fatemi R, Ferreira VS, Burgos LF, Forati E, Fowler AG, Foxen B, Genois É, Giang W, Gidney C, Gilboa D, Giustina M, Gosula R, Gross JA, Habegger S, Hamilton MC, Hansen M, Harrigan MP, Harrington SD, Heu P, Hoffmann MR, Hong S, Huang T, Huff A, Huggins WJ, Ioffe LB, Isakov SV, Iveland J, Jeffrey E, Jiang Z, Jones C, Juhas P, Kafri D, Kechedzhi K, Khattar T, Khezri M, Kieferová M, Kim S, Kitaev A, Klots AR, Korotkov AN, Kostritsa F, Kreikebaum JM, Landhuis D, Laptev P, Lau KM, Laws L, Lee J, Lee KW, Lensky YD, Lester BJ, Lill AT, Liu W, Locharla A, Malone FD, Martin O, McClean JR, McEwen M, Mieszala A, Montazeri S, Morvan A, Movassagh R, Mruczkiewicz W, Neeley M, Neill C, Nersisyan A, Newman M, Ng JH, Nguyen A, Nguyen M, Niu MY, O'Brien TE, Opremcak A, Petukhov A, Potter R, Pryadko LP, Quintana C, Rocque C, Rubin NC, Saei N, Sank D, Sankaragomathi K, Satzinger KJ, Schurkus HF, Schuster C, Shearn MJ, Shorter A, Shutty N, Shvarts V, Skruzny J, Smith WC, Somma R, Sterling G, Strain D, Szalay M, Torres A, Vidal G, Villalonga B, Heidweiller CV, White T, Woo BWK, Xing C, Yao ZJ, Yeh P, Yoo J, Young G, Zalcman A, Zhang Y, Zhu N, Zobrist N, Neven H, Babbush R, Bacon D, Boixo S, Hilton J, Lucero E, Megrant A, Kelly J, Chen Y, Roushan P, Smelyanskiy V, Abanin DA. Stable quantum-correlated many-body states through engineered dissipation. Science 2024; 383:1332-1337. [PMID: 38513021 DOI: 10.1126/science.adh9932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 02/13/2024] [Indexed: 03/23/2024]
Abstract
Engineered dissipative reservoirs have the potential to steer many-body quantum systems toward correlated steady states useful for quantum simulation of high-temperature superconductivity or quantum magnetism. Using up to 49 superconducting qubits, we prepared low-energy states of the transverse-field Ising model through coupling to dissipative auxiliary qubits. In one dimension, we observed long-range quantum correlations and a ground-state fidelity of 0.86 for 18 qubits at the critical point. In two dimensions, we found mutual information that extends beyond nearest neighbors. Lastly, by coupling the system to auxiliaries emulating reservoirs with different chemical potentials, we explored transport in the quantum Heisenberg model. Our results establish engineered dissipation as a scalable alternative to unitary evolution for preparing entangled many-body states on noisy quantum processors.
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Affiliation(s)
- X Mi
- Google Research, Mountain View, CA, USA
| | - A A Michailidis
- Department of Theoretical Physics, University of Geneva, Geneva, Switzerland
| | - S Shabani
- Google Research, Mountain View, CA, USA
| | - K C Miao
- Google Research, Mountain View, CA, USA
| | | | - J Lloyd
- Department of Theoretical Physics, University of Geneva, Geneva, Switzerland
| | | | - R Acharya
- Google Research, Mountain View, CA, USA
| | - I Aleiner
- Google Research, Mountain View, CA, USA
| | | | - M Ansmann
- Google Research, Mountain View, CA, USA
| | - F Arute
- Google Research, Mountain View, CA, USA
| | - K Arya
- Google Research, Mountain View, CA, USA
| | - A Asfaw
- Google Research, Mountain View, CA, USA
| | - J Atalaya
- Google Research, Mountain View, CA, USA
| | - J C Bardin
- Google Research, Mountain View, CA, USA
- Department of Electrical and Computer Engineering, University of Massachusetts, Amherst, MA, USA
| | | | - G Bortoli
- Google Research, Mountain View, CA, USA
| | | | - J Bovaird
- Google Research, Mountain View, CA, USA
| | - L Brill
- Google Research, Mountain View, CA, USA
| | | | | | - D A Buell
- Google Research, Mountain View, CA, USA
| | - T Burger
- Google Research, Mountain View, CA, USA
| | - B Burkett
- Google Research, Mountain View, CA, USA
| | | | - Z Chen
- Google Research, Mountain View, CA, USA
| | - B Chiaro
- Google Research, Mountain View, CA, USA
| | - D Chik
- Google Research, Mountain View, CA, USA
| | - C Chou
- Google Research, Mountain View, CA, USA
| | - J Cogan
- Google Research, Mountain View, CA, USA
| | - R Collins
- Google Research, Mountain View, CA, USA
| | - P Conner
- Google Research, Mountain View, CA, USA
| | | | - A L Crook
- Google Research, Mountain View, CA, USA
| | - B Curtin
- Google Research, Mountain View, CA, USA
| | - A G Dau
- Google Research, Mountain View, CA, USA
| | | | | | - S Demura
- Google Research, Mountain View, CA, USA
| | | | | | | | | | - L Faoro
- Google Research, Mountain View, CA, USA
| | - E Farhi
- Google Research, Mountain View, CA, USA
| | - R Fatemi
- Google Research, Mountain View, CA, USA
| | | | | | - E Forati
- Google Research, Mountain View, CA, USA
| | | | - B Foxen
- Google Research, Mountain View, CA, USA
| | - É Genois
- Google Research, Mountain View, CA, USA
| | - W Giang
- Google Research, Mountain View, CA, USA
| | - C Gidney
- Google Research, Mountain View, CA, USA
| | - D Gilboa
- Google Research, Mountain View, CA, USA
| | | | - R Gosula
- Google Research, Mountain View, CA, USA
| | - J A Gross
- Google Research, Mountain View, CA, USA
| | | | - M C Hamilton
- Google Research, Mountain View, CA, USA
- Department of Electrical and Computer Engineering, Auburn University, Auburn, AL, USA
| | - M Hansen
- Google Research, Mountain View, CA, USA
| | | | | | - P Heu
- Google Research, Mountain View, CA, USA
| | | | - S Hong
- Google Research, Mountain View, CA, USA
| | - T Huang
- Google Research, Mountain View, CA, USA
| | - A Huff
- Google Research, Mountain View, CA, USA
| | | | - L B Ioffe
- Google Research, Mountain View, CA, USA
| | | | - J Iveland
- Google Research, Mountain View, CA, USA
| | - E Jeffrey
- Google Research, Mountain View, CA, USA
| | - Z Jiang
- Google Research, Mountain View, CA, USA
| | - C Jones
- Google Research, Mountain View, CA, USA
| | - P Juhas
- Google Research, Mountain View, CA, USA
| | - D Kafri
- Google Research, Mountain View, CA, USA
| | | | - T Khattar
- Google Research, Mountain View, CA, USA
| | - M Khezri
- Google Research, Mountain View, CA, USA
| | - M Kieferová
- Google Research, Mountain View, CA, USA
- Centre for Quantum Software and Information (QSI), Faculty of Engineering and Information Technology, University of Technology Sydney, Sydney, NSW, Australia
| | - S Kim
- Google Research, Mountain View, CA, USA
| | - A Kitaev
- Google Research, Mountain View, CA, USA
| | - A R Klots
- Google Research, Mountain View, CA, USA
| | - A N Korotkov
- Google Research, Mountain View, CA, USA
- Department of Electrical and Computer Engineering, University of California, Riverside, CA, USA
| | | | | | | | - P Laptev
- Google Research, Mountain View, CA, USA
| | - K-M Lau
- Google Research, Mountain View, CA, USA
| | - L Laws
- Google Research, Mountain View, CA, USA
| | - J Lee
- Google Research, Mountain View, CA, USA
- Department of Chemistry, Columbia University, New York, NY, USA
| | - K W Lee
- Google Research, Mountain View, CA, USA
| | | | | | - A T Lill
- Google Research, Mountain View, CA, USA
| | - W Liu
- Google Research, Mountain View, CA, USA
| | | | | | - O Martin
- Google Research, Mountain View, CA, USA
| | | | - M McEwen
- Google Research, Mountain View, CA, USA
| | | | | | - A Morvan
- Google Research, Mountain View, CA, USA
| | | | | | - M Neeley
- Google Research, Mountain View, CA, USA
| | - C Neill
- Google Research, Mountain View, CA, USA
| | | | - M Newman
- Google Research, Mountain View, CA, USA
| | - J H Ng
- Google Research, Mountain View, CA, USA
| | - A Nguyen
- Google Research, Mountain View, CA, USA
| | - M Nguyen
- Google Research, Mountain View, CA, USA
| | - M Y Niu
- Google Research, Mountain View, CA, USA
| | | | | | | | - R Potter
- Google Research, Mountain View, CA, USA
| | - L P Pryadko
- Google Research, Mountain View, CA, USA
- Department of Physics and Astronomy, University of California, Riverside, CA, USA
| | | | - C Rocque
- Google Research, Mountain View, CA, USA
| | - N C Rubin
- Google Research, Mountain View, CA, USA
| | - N Saei
- Google Research, Mountain View, CA, USA
| | - D Sank
- Google Research, Mountain View, CA, USA
| | | | | | | | | | | | - A Shorter
- Google Research, Mountain View, CA, USA
| | - N Shutty
- Google Research, Mountain View, CA, USA
| | - V Shvarts
- Google Research, Mountain View, CA, USA
| | - J Skruzny
- Google Research, Mountain View, CA, USA
| | - W C Smith
- Google Research, Mountain View, CA, USA
| | - R Somma
- Google Research, Mountain View, CA, USA
| | | | - D Strain
- Google Research, Mountain View, CA, USA
| | - M Szalay
- Google Research, Mountain View, CA, USA
| | - A Torres
- Google Research, Mountain View, CA, USA
| | - G Vidal
- Google Research, Mountain View, CA, USA
| | | | | | - T White
- Google Research, Mountain View, CA, USA
| | - B W K Woo
- Google Research, Mountain View, CA, USA
| | - C Xing
- Google Research, Mountain View, CA, USA
| | - Z J Yao
- Google Research, Mountain View, CA, USA
| | - P Yeh
- Google Research, Mountain View, CA, USA
| | - J Yoo
- Google Research, Mountain View, CA, USA
| | - G Young
- Google Research, Mountain View, CA, USA
| | - A Zalcman
- Google Research, Mountain View, CA, USA
| | - Y Zhang
- Google Research, Mountain View, CA, USA
| | - N Zhu
- Google Research, Mountain View, CA, USA
| | - N Zobrist
- Google Research, Mountain View, CA, USA
| | - H Neven
- Google Research, Mountain View, CA, USA
| | - R Babbush
- Google Research, Mountain View, CA, USA
| | - D Bacon
- Google Research, Mountain View, CA, USA
| | - S Boixo
- Google Research, Mountain View, CA, USA
| | - J Hilton
- Google Research, Mountain View, CA, USA
| | - E Lucero
- Google Research, Mountain View, CA, USA
| | - A Megrant
- Google Research, Mountain View, CA, USA
| | - J Kelly
- Google Research, Mountain View, CA, USA
| | - Y Chen
- Google Research, Mountain View, CA, USA
| | - P Roushan
- Google Research, Mountain View, CA, USA
| | | | - D A Abanin
- Google Research, Mountain View, CA, USA
- Department of Theoretical Physics, University of Geneva, Geneva, Switzerland
- Department of Physics, Princeton University, Princeton, NJ, USA
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19
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Kumar V, Roy D. Many-body quantum chaos in mixtures of multiple species. Phys Rev E 2024; 109:L032201. [PMID: 38632778 DOI: 10.1103/physreve.109.l032201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 02/15/2024] [Indexed: 04/19/2024]
Abstract
We study spectral correlations in many-body quantum mixtures of fermions, bosons, and qubits with periodically kicked spreading and mixing of species. We take two types of mixing, namely, Jaynes-Cummings and Rabi, respectively, satisfying and breaking the conservation of a total number of species. We analytically derive the generating Hamiltonians whose spectral properties determine the spectral form factor in the leading order. We further analyze the system-size (L) scaling of Thouless time t^{*}, beyond which the spectral form factor follows the prediction of random matrix theory. The L dependence of t^{*} crosses over from lnL to L^{2} with an increasing Jaynes-Cummings mixing between qubits and fermions or bosons in a finite-size chain, and it finally settles to t^{*}∝O(L^{2}) in the thermodynamic limit for any mixing strength. The Rabi mixing between qubits and fermions leads to t^{*}∝O(lnL), previously predicted for single species of qubits or fermions without total-number conservation.
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Affiliation(s)
- Vijay Kumar
- Raman Research Institute, Bangalore 560080, India
| | - Dibyendu Roy
- Raman Research Institute, Bangalore 560080, India
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20
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Lim LK, Lou C, Tian C. Mesoscopic fluctuations in entanglement dynamics. Nat Commun 2024; 15:1775. [PMID: 38413673 PMCID: PMC10899636 DOI: 10.1038/s41467-024-46078-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 02/12/2024] [Indexed: 02/29/2024] Open
Abstract
Understanding fluctuation phenomena plays a dominant role in the development of many-body physics. The time evolution of entanglement is essential to a broad range of subjects in many-body physics, ranging from exotic quantum matter to quantum thermalization. Stemming from various dynamical processes of information, fluctuations in entanglement evolution differ conceptually from out-of-equilibrium fluctuations of traditional physical quantities. Their studies remain elusive. Here we uncover an emergent random structure in the evolution of the many-body wavefunction in two classes of integrable-either interacting or noninteracting-lattice models. It gives rise to out-of-equilibrium entanglement fluctuations which fall into the paradigm of mesoscopic fluctuations of wave interference origin. Specifically, the entanglement entropy variance obeys a universal scaling law in each class, and the full distribution displays a sub-Gaussian upper and a sub-Gamma lower tail. These statistics are independent of both the system's microscopic details and the choice of entanglement probes, and broaden the class of mesoscopic universalities. They have practical implications for controlling entanglement in mesoscopic devices.
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Affiliation(s)
- Lih-King Lim
- School of Physics, Zhejiang University, 310027, Hangzhou, Zhejiang, China
| | - Cunzhong Lou
- School of Physics, Zhejiang University, 310027, Hangzhou, Zhejiang, China
| | - Chushun Tian
- CAS Key Laboratory of Theoretical Physics and Institute of Theoretical Physics, Chinese Academy of Sciences, 100190, Beijing, China.
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21
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Bluvstein D, Evered SJ, Geim AA, Li SH, Zhou H, Manovitz T, Ebadi S, Cain M, Kalinowski M, Hangleiter D, Bonilla Ataides JP, Maskara N, Cong I, Gao X, Sales Rodriguez P, Karolyshyn T, Semeghini G, Gullans MJ, Greiner M, Vuletić V, Lukin MD. Logical quantum processor based on reconfigurable atom arrays. Nature 2024; 626:58-65. [PMID: 38056497 PMCID: PMC10830422 DOI: 10.1038/s41586-023-06927-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Accepted: 12/01/2023] [Indexed: 12/08/2023]
Abstract
Suppressing errors is the central challenge for useful quantum computing1, requiring quantum error correction (QEC)2-6 for large-scale processing. However, the overhead in the realization of error-corrected 'logical' qubits, in which information is encoded across many physical qubits for redundancy2-4, poses substantial 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. Using logical-level control and a zoned architecture in reconfigurable neutral-atom arrays7, our system combines high two-qubit gate fidelities8, arbitrary connectivity7,9, as well as fully programmable single-qubit rotations and mid-circuit readout10-15. Operating this logical processor with various types of encoding, we demonstrate improvement of a two-qubit logic gate by scaling surface-code6 distance from d = 3 to d = 7, preparation of colour-code qubits with break-even fidelities5, fault-tolerant creation of logical Greenberger-Horne-Zeilinger (GHZ) states and feedforward entanglement teleportation, as well as operation of 40 colour-code qubits. Finally, using 3D [[8,3,2]] code blocks16,17, we realize computationally complex sampling circuits18 with up to 48 logical qubits entangled with hypercube connectivity19 with 228 logical two-qubit gates and 48 logical CCZ gates20. 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 scrambling21,22. These results herald the advent of early error-corrected quantum computation and chart a path towards large-scale logical processors.
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Affiliation(s)
- Dolev Bluvstein
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Simon J Evered
- Department of Physics, Harvard University, Cambridge, MA, USA
| | | | - Sophie H Li
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Hengyun Zhou
- Department of Physics, Harvard University, Cambridge, MA, USA
- QuEra Computing Inc., Boston, MA, USA
| | - Tom Manovitz
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Sepehr Ebadi
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Madelyn Cain
- Department of Physics, Harvard University, Cambridge, MA, USA
| | | | - Dominik Hangleiter
- Joint Center for Quantum Information and Computer Science, NIST/University of Maryland, College Park, MD, USA
| | | | - Nishad Maskara
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Iris Cong
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Xun Gao
- Department of Physics, Harvard University, Cambridge, MA, USA
| | | | | | - Giulia Semeghini
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Michael J Gullans
- Joint Center for Quantum Information and Computer Science, NIST/University of Maryland, College Park, MD, USA
| | - Markus Greiner
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Vladan Vuletić
- Department of Physics and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Mikhail D Lukin
- Department of Physics, Harvard University, Cambridge, MA, USA.
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22
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Maletskii EA, Iakovlev IA, Mazurenko VV. Quantifying spatiotemporal patterns in classical and quantum systems out of equilibrium. Phys Rev E 2024; 109:024105. [PMID: 38491697 DOI: 10.1103/physreve.109.024105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 12/28/2023] [Indexed: 03/18/2024]
Abstract
A rich variety of nonequilibrium dynamical phenomena and processes unambiguously calls for the development of general numerical techniques to probe and estimate a complex interplay between spatial and temporal degrees of freedom in many-body systems of completely different nature. In this work we provide a solution to this problem by adopting a structural complexity measure to quantify spatiotemporal patterns in the time-dependent digital representation of a system. On the basis of very limited amount of data our approach allows us to distinguish different dynamical regimes and define critical parameters in both classical and quantum systems. By the example of the discrete time crystal realized in nonequilibrium quantum systems we provide a complete low-level characterization of this nontrivial dynamical phase with only processing bitstrings, which can be considered as a valuable alternative to previous studies based on the calculations of qubit correlation functions.
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Affiliation(s)
- E A Maletskii
- Theoretical Physics and Applied Mathematics Department, Ural Federal University, Mira Street 19, 620002 Ekaterinburg, Russia
| | - I A Iakovlev
- Theoretical Physics and Applied Mathematics Department, Ural Federal University, Mira Street 19, 620002 Ekaterinburg, Russia
| | - V V Mazurenko
- Theoretical Physics and Applied Mathematics Department, Ural Federal University, Mira Street 19, 620002 Ekaterinburg, Russia
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23
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Sinha S, Ray S, Sinha S. Classical route to ergodicity and scarring in collective quantum systems. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:163001. [PMID: 38190726 DOI: 10.1088/1361-648x/ad1bf5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2023] [Accepted: 01/08/2024] [Indexed: 01/10/2024]
Abstract
Ergodicity, a fundamental concept in statistical mechanics, is not yet a fully understood phenomena for closed quantum systems, particularly its connection with the underlying chaos. In this review, we consider a few examples of collective quantum systems to unveil the intricate relationship of ergodicity as well as its deviation due to quantum scarring phenomena with their classical counterpart. A comprehensive overview of classical and quantum chaos is provided, along with the tools essential for their detection. Furthermore, we survey recent theoretical and experimental advancements in the domain of ergodicity and its violations. This review aims to illuminate the classical perspective of quantum scarring phenomena in interacting quantum systems.
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Affiliation(s)
- Sudip Sinha
- Indian Institute of Science Education and Research Kolkata, Mohanpur, Nadia 741246, India
| | - Sayak Ray
- Physikalisches Institut, Universität Bonn, Nußallee 12, 53115 Bonn, Germany
| | - Subhasis Sinha
- Indian Institute of Science Education and Research Kolkata, Mohanpur, Nadia 741246, India
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24
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Bao Y, Block M, Altman E. Finite-Time Teleportation Phase Transition in Random Quantum Circuits. PHYSICAL REVIEW LETTERS 2024; 132:030401. [PMID: 38307063 DOI: 10.1103/physrevlett.132.030401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Accepted: 12/19/2023] [Indexed: 02/04/2024]
Abstract
How long does it take to entangle two distant qubits in a quantum circuit evolved by generic unitary dynamics? We show that if the time evolution is followed by measurements of all but two infinitely separated test qubits, then the entanglement between them can undergo a phase transition and become nonzero at a finite critical time t_{c}. The fidelity of teleporting a quantum state from an input qubit to an infinitely distant output qubit shows the same critical onset. Specifically, these finite-time transitions occur in short-range interacting two-dimensional random unitary circuits and in sufficiently long-range interacting one-dimensional circuits. The phase transition is understood by mapping the random continuous-time evolution to a finite-temperature thermal state of an effective spin Hamiltonian, where the inverse temperature equals the evolution time in the circuit. In this framework, the entanglement between two distant qubits at times t>t_{c} corresponds to the emergence of long-range ferromagnetic spin correlations below the critical temperature. We verify these predictions using numerical simulation of Clifford circuits and propose potential realizations in existing platforms for quantum simulation.
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Affiliation(s)
- Yimu Bao
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - Maxwell Block
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - Ehud Altman
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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25
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Di Carli A, Parsonage C, La Rooij A, Koehn L, Ulm C, Duncan CW, Daley AJ, Haller E, Kuhr S. Commensurate and incommensurate 1D interacting quantum systems. Nat Commun 2024; 15:474. [PMID: 38212298 PMCID: PMC10784295 DOI: 10.1038/s41467-023-44610-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 12/19/2023] [Indexed: 01/13/2024] Open
Abstract
Single-atom imaging resolution of many-body quantum systems in optical lattices is routinely achieved with quantum-gas microscopes. Key to their great versatility as quantum simulators is the ability to use engineered light potentials at the microscopic level. Here, we employ dynamically varying microscopic light potentials in a quantum-gas microscope to study commensurate and incommensurate 1D systems of interacting bosonic Rb atoms. Such incommensurate systems are analogous to doped insulating states that exhibit atom transport and compressibility. Initially, a commensurate system with unit filling and fixed atom number is prepared between two potential barriers. We deterministically create an incommensurate system by dynamically changing the position of the barriers such that the number of available lattice sites is reduced while retaining the atom number. Our systems are characterised by measuring the distribution of particles and holes as a function of the lattice filling, and interaction strength, and we probe the particle mobility by applying a bias potential. Our work provides the foundation for preparation of low-entropy states with controlled filling in optical-lattice experiments.
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Affiliation(s)
- Andrea Di Carli
- Department of Physics, SUPA, University of Strathclyde, Glasgow, G4 0NG, United Kingdom
| | - Christopher Parsonage
- Department of Physics, SUPA, University of Strathclyde, Glasgow, G4 0NG, United Kingdom
| | - Arthur La Rooij
- Department of Physics, SUPA, University of Strathclyde, Glasgow, G4 0NG, United Kingdom
| | - Lennart Koehn
- Department of Physics, SUPA, University of Strathclyde, Glasgow, G4 0NG, United Kingdom
| | - Clemens Ulm
- Department of Physics, SUPA, University of Strathclyde, Glasgow, G4 0NG, United Kingdom
| | - Callum W Duncan
- Department of Physics, SUPA, University of Strathclyde, Glasgow, G4 0NG, United Kingdom
| | - Andrew J Daley
- Department of Physics, SUPA, University of Strathclyde, Glasgow, G4 0NG, United Kingdom
| | - Elmar Haller
- Department of Physics, SUPA, University of Strathclyde, Glasgow, G4 0NG, United Kingdom
| | - Stefan Kuhr
- Department of Physics, SUPA, University of Strathclyde, Glasgow, G4 0NG, United Kingdom.
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26
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Reichl LE, Estrella F. Particle-hole thermalization in a composite superconducting and normal-conducting nanowire. Phys Rev E 2024; 109:014226. [PMID: 38366481 DOI: 10.1103/physreve.109.014226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 01/03/2024] [Indexed: 02/18/2024]
Abstract
The mechanisms by which isolated condensed matter systems thermalize is a topic of growing interest. Thermalization is known to be linked to the emergence of chaos in the dynamics of a system. We show that a solid state scattering system, containing superconducting elements, can thermalize scattered states without affecting the degree of entanglement of the scattered states. We consider a composite NSNSNSNSN nanowire composed of Bi_{2}Sr_{2}CaCu_{2}O_{8+x} superconducting segments (S) and normal conducting segments (N). We consider parameter regimes where all current flow is due to tunneling currents that are facilitated by quasibound state resonances inside the SNSNSNS structure. At certain energies, scattered pure states approach ergodicity, even though they remain pure.
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Affiliation(s)
- L E Reichl
- Center for Complex Quantum Systems and Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA
| | - F Estrella
- Center for Complex Quantum Systems and Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA
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27
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Ogunnaike O, Feldmeier J, Lee JY. Unifying Emergent Hydrodynamics and Lindbladian Low-Energy Spectra across Symmetries, Constraints, and Long-Range Interactions. PHYSICAL REVIEW LETTERS 2023; 131:220403. [PMID: 38101343 DOI: 10.1103/physrevlett.131.220403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 08/30/2023] [Accepted: 10/23/2023] [Indexed: 12/17/2023]
Abstract
We identify emergent hydrodynamics governing charge transport in Brownian random time evolution with various symmetries, constraints, and ranges of interactions. This is accomplished via a mapping between the averaged dynamics and the low-energy spectrum of a Lindblad operator, which acts as an effective Hamiltonian in a doubled Hilbert space. By explicitly constructing dispersive excited states of this effective Hamiltonian using a single-mode approximation, we provide a comprehensive understanding of diffusive, subdiffusive, and superdiffusive relaxation in many-body systems with conserved multipole moments and variable interaction ranges. Our approach further allows us to identify exotic Krylov-space-resolved diffusive relaxation despite the presence of dipole conservation, which we verify numerically. Therefore, we provide a general and versatile framework to qualitatively understand the dynamics of conserved operators under random unitary time evolution.
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Affiliation(s)
- Olumakinde Ogunnaike
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Johannes Feldmeier
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Jong Yeon Lee
- Kavli Institute for Theoretical Physics, University of California, Santa Barbara, California 93106, USA
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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28
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Mitra A, Srivastava SCL. Sunburst quantum Ising model under interaction quench: Entanglement and role of initial state coherence. Phys Rev E 2023; 108:054114. [PMID: 38115417 DOI: 10.1103/physreve.108.054114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 10/13/2023] [Indexed: 12/21/2023]
Abstract
We study the nonequilibrium dynamics of an isolated bipartite quantum system, the sunburst quantum Ising model, under interaction quench. The prequench limit of this model is two noninteracting integrable systems, namely a transverse Ising chain and finite number of isolated qubits. As a function of interaction strength, the spectral fluctuation property goes from Poisson to Wigner-Dyson statistics. We chose entanglement entropy as a probe to study the approach to thermalization or lack of it in postquench dynamics. In the near-integrable limit, as expected, the linear entropy displays oscillatory behavior, while in the chaotic limit it saturates. Along with the chaotic nature of the time evolution generator, we show the importance of the role played by the coherence of the initial state in deciding the nature of thermalization. We further show that these findings are general by replacing the Ising ring with a disordered XXZ model with disorder strength putting it in the many-body localized phase.
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Affiliation(s)
- Akash Mitra
- Variable Energy Cyclotron Centre, 1/AF Bidhannagar, Kolkata 700064, India and Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai 400094, India
| | - Shashi C L Srivastava
- Variable Energy Cyclotron Centre, 1/AF Bidhannagar, Kolkata 700064, India and Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai 400094, India
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29
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Roscilde T, Comparin T, Mezzacapo F. Entangling Dynamics from Effective Rotor-Spin-Wave Separation in U(1)-Symmetric Quantum Spin Models. PHYSICAL REVIEW LETTERS 2023; 131:160403. [PMID: 37925736 DOI: 10.1103/physrevlett.131.160403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 07/14/2023] [Accepted: 09/05/2023] [Indexed: 11/07/2023]
Abstract
The nonequilibrium dynamics of quantum spin models is a most challenging topic, due to the exponentiality of Hilbert space, and it is central to the understanding of the many-body entangled states that can be generated by state-of-the-art quantum simulators. A particularly important class of evolutions is the one governed by U(1)-symmetric Hamiltonians, initialized in a state that breaks the U(1) symmetry-the paradigmatic example being the evolution of the so-called one-axis-twisting (OAT) model, featuring infinite-range interactions between spins. In this Letter, we show that the dynamics of the OAT model can be closely reproduced by systems with power-law-decaying interactions, thanks to an effective separation between the zero-momentum degrees of freedom, associated with the so-called Anderson tower of states, and reconstructing an OAT model, as well as finite-momentum ones, associated with spin-wave excitations. This mechanism explains quantitatively the recent numerical observation of spin squeezing and Schrödinger cat-state generation in the dynamics of dipolar Hamiltonians, and it paves the way for the extension of this observation to a much larger class of models of immediate relevance for quantum simulations.
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Affiliation(s)
- Tommaso Roscilde
- Univ Lyon, Ens de Lyon, CNRS, Laboratoire de Physique, F-69342 Lyon, France
| | - Tommaso Comparin
- Univ Lyon, Ens de Lyon, CNRS, Laboratoire de Physique, F-69342 Lyon, France
| | - Fabio Mezzacapo
- Univ Lyon, Ens de Lyon, CNRS, Laboratoire de Physique, F-69342 Lyon, France
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30
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Gärttner M, Haas T, Noll J. General Class of Continuous Variable Entanglement Criteria. PHYSICAL REVIEW LETTERS 2023; 131:150201. [PMID: 37897784 DOI: 10.1103/physrevlett.131.150201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 08/30/2023] [Indexed: 10/30/2023]
Abstract
We present a general class of entanglement criteria for continuous variable systems. Our criteria are based on the Husimi Q distribution and allow for optimization over the set of all concave functions rendering them extremely general and versatile. We show that several entropic criteria and second moment criteria are obtained as special cases. Our criteria reveal entanglement of families of states undetected by any commonly used criteria and provide clear advantages under typical experimental constraints such as finite detector resolution and measurement statistics.
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Affiliation(s)
- Martin Gärttner
- Institut für Theoretische Physik, Universität Heidelberg, Philosophenweg 16, 69120 Heidelberg, Germany
- Physikalisches Institut, Universität Heidelberg, Im Neuenheimer Feld 226, 69120 Heidelberg, Germany
- Kirchhoff-Institut für Physik, Universität Heidelberg, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany
- Institute of Condensed Matter Theory and Optics, Friedrich-Schiller-University Jena, Max-Wien-Platz 1, D-07743 Jena, Germany
| | - Tobias Haas
- Centre for Quantum Information and Communication, École polytechnique de Bruxelles, CP 165, Université libre de Bruxelles, 1050 Brussels, Belgium
| | - Johannes Noll
- Kirchhoff-Institut für Physik, Universität Heidelberg, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany
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31
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Chatterjee P, Modak R. One-dimensional Lévy quasicrystal. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 35:505602. [PMID: 37708897 DOI: 10.1088/1361-648x/acf9d4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Accepted: 09/14/2023] [Indexed: 09/16/2023]
Abstract
Space-fractional quantum mechanics (SFQM) is a generalization of the standard quantum mechanics when the Brownian trajectories in Feynman path integrals are replaced by Lévy flights. We introduce Lévy quasicrystal by discretizing the space-fractional Schrödinger equation using the Grünwald-Letnikov derivatives and adding on-site quasiperiodic potential. The discretized version of the usual Schrödinger equation maps to the Aubry-André (AA) Hamiltonian, which supports localization-delocalization transition even in one dimension. We find the similarities between Lévy quasicrystal and the AA model with power-law hopping, and show that the Lévy quasicrystal supports a delocalization-localization transition as one tunes the quasiperiodic potential strength and shows the coexistence of localized and delocalized states separated by mobility edge. Hence, a possible realization of SFQM in optical experiments should be a new experimental platform to test the predictions of AA models in the presence of power-law hopping.
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Affiliation(s)
- Pallabi Chatterjee
- Department of Physics, Indian Institute of Technology Tirupati, Tirupati 517619, India
| | - Ranjan Modak
- Department of Physics, Indian Institute of Technology Tirupati, Tirupati 517619, India
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32
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Mark DK, Choi J, Shaw AL, Endres M, Choi S. Benchmarking Quantum Simulators Using Ergodic Quantum Dynamics. PHYSICAL REVIEW LETTERS 2023; 131:110601. [PMID: 37774308 DOI: 10.1103/physrevlett.131.110601] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 08/15/2023] [Indexed: 10/01/2023]
Abstract
We propose and analyze a sample-efficient protocol to estimate the fidelity between an experimentally prepared state and an ideal target state, applicable to a wide class of analog quantum simulators without advanced spatiotemporal control. Our protocol relies on universal fluctuations emerging from generic Hamiltonian dynamics, which we discover in the present work. It does not require fine-tuned control over state preparation, quantum evolution, or readout capability, while achieving near optimal sample complexity: a percent-level precision is obtained with ∼10^{3} measurements, independent of system size. Furthermore, the accuracy of our fidelity estimation improves exponentially with increasing system size. We numerically demonstrate our protocol in a variety of quantum simulator platforms, including quantum gas microscopes, trapped ions, and Rydberg atom arrays. We discuss applications of our method for tasks such as multiparameter estimation of quantum states and processes.
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Affiliation(s)
- Daniel K Mark
- Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Joonhee Choi
- California Institute of Technology, Pasadena, California 91125, USA
| | - Adam L Shaw
- California Institute of Technology, Pasadena, California 91125, USA
| | - Manuel Endres
- California Institute of Technology, Pasadena, California 91125, USA
| | - Soonwon Choi
- Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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33
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Eckner WJ, Darkwah Oppong N, Cao A, Young AW, Milner WR, Robinson JM, Ye J, Kaufman AM. Realizing spin squeezing with Rydberg interactions in an optical clock. Nature 2023; 621:734-739. [PMID: 37648865 DOI: 10.1038/s41586-023-06360-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 06/22/2023] [Indexed: 09/01/2023]
Abstract
Neutral-atom arrays trapped in optical potentials are a powerful platform for studying quantum physics, combining precise single-particle control and detection with a range of tunable entangling interactions1-3. For example, these capabilities have been leveraged for state-of-the-art frequency metrology4,5 as well as microscopic studies of entangled many-particle states6-11. Here we combine these applications to realize spin squeezing-a widely studied operation for producing metrologically useful entanglement-in an optical atomic clock based on a programmable array of interacting optical qubits. In this demonstration of Rydberg-mediated squeezing with a neutral-atom optical clock, we generate states that have almost four decibels of metrological gain. In addition, we perform a synchronous frequency comparison between independent squeezed states and observe a fractional-frequency stability of 1.087(1) × 10-15 at one-second averaging time, which is 1.94(1) decibels below the standard quantum limit and reaches a fractional precision at the 10-17 level during a half-hour measurement. We further leverage the programmable control afforded by optical tweezer arrays to apply local phase shifts to explore spin squeezing in measurements that operate beyond the relative coherence time with the optical local oscillator. The realization of this spin-squeezing protocol in a programmable atom-array clock will enable a wide range of quantum-information-inspired techniques for optimal phase estimation and Heisenberg-limited optical atomic clocks12-16.
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Affiliation(s)
- William J Eckner
- JILA, University of Colorado and National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, Colorado, USA
| | - Nelson Darkwah Oppong
- JILA, University of Colorado and National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, Colorado, USA
| | - Alec Cao
- JILA, University of Colorado and National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, Colorado, USA
| | - Aaron W Young
- JILA, University of Colorado and National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, Colorado, USA
| | - William R Milner
- JILA, University of Colorado and National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, Colorado, USA
| | - John M Robinson
- JILA, University of Colorado and National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, Colorado, USA
| | - Jun Ye
- JILA, University of Colorado and National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, Colorado, USA
| | - Adam M Kaufman
- JILA, University of Colorado and National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, Colorado, USA.
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34
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Heitmann T, Richter J, Herbrych J, Gemmer J, Steinigeweg R. Real-time broadening of bath-induced density profiles from closed-system correlation functions. Phys Rev E 2023; 108:024102. [PMID: 37723681 DOI: 10.1103/physreve.108.024102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 07/08/2023] [Indexed: 09/20/2023]
Abstract
The Lindblad master equation is one of the main approaches to open quantum systems. While it has been widely applied in the context of condensed matter systems to study properties of steady states in the limit of long times, the actual route to such steady states has attracted less attention yet. Here, we investigate the nonequilibrium dynamics of spin chains with a local coupling to a single Lindblad bath and analyze the transport properties of the induced magnetization. Combining typicality and equilibration arguments with stochastic unraveling, we unveil for the case of weak driving that the dynamics in the open system can be constructed on the basis of correlation functions in the closed system, which establishes a connection between the Lindblad approach and linear response theory at finite times. In this way, we provide a particular example where closed and open approaches to quantum transport agree strictly. We demonstrate this fact numerically for the spin-1/2 XXZ chain at the isotropic point and in the easy-axis regime, where superdiffusive and diffusive scaling is observed, respectively.
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Affiliation(s)
- Tjark Heitmann
- Department of Mathematics/Computer Science/Physics, University of Osnabrück, D-49076 Osnabrück, Germany
| | - Jonas Richter
- Department of Physics, Stanford University, Stanford, California 94305, USA
- Institut für Theoretische Physik, Leibniz Universität Hannover, Appelstraße 2, D-30167 Hannover, Germany
| | - Jacek Herbrych
- Institute of Theoretical Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, 50-370 Wrocław, Poland
| | - Jochen Gemmer
- Department of Mathematics/Computer Science/Physics, University of Osnabrück, D-49076 Osnabrück, Germany
| | - Robin Steinigeweg
- Department of Mathematics/Computer Science/Physics, University of Osnabrück, D-49076 Osnabrück, Germany
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35
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Alruqi AB, Khalil E, Abdel-Khalek S, Abd-Rabbou M. Visualization of the interaction dynamics between a two-level atom and a graphene sheet covered by a laser field. ALEXANDRIA ENGINEERING JOURNAL 2023; 77:309-317. [DOI: 10.1016/j.aej.2023.06.075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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36
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Koutný D, Ginés L, Moczała-Dusanowska M, Höfling S, Schneider C, Predojević A, Ježek M. Deep learning of quantum entanglement from incomplete measurements. SCIENCE ADVANCES 2023; 9:eadd7131. [PMID: 37467336 DOI: 10.1126/sciadv.add7131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 06/16/2023] [Indexed: 07/21/2023]
Abstract
The quantification of the entanglement present in a physical system is of paramount importance for fundamental research and many cutting-edge applications. Now, achieving this goal requires either a priori knowledge on the system or very demanding experimental procedures such as full state tomography or collective measurements. Here, we demonstrate that, by using neural networks, we can quantify the degree of entanglement without the need to know the full description of the quantum state. Our method allows for direct quantification of the quantum correlations using an incomplete set of local measurements. Despite using undersampled measurements, we achieve a quantification error of up to an order of magnitude lower than the state-of-the-art quantum tomography. Furthermore, we achieve this result using networks trained using exclusively simulated data. Last, we derive a method based on a convolutional network input that can accept data from various measurement scenarios and perform, to some extent, independently of the measurement device.
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Affiliation(s)
- Dominik Koutný
- Department of Optics, Faculty of Science, Palacký University, 17. listopadu 12, 77146 Olomouc, Czechia
| | - Laia Ginés
- Department of Physics, Stockholm University, 10691 Stockholm, Sweden
| | | | - Sven Höfling
- Technische Physik, Physikalisches Institut and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | | | - Ana Predojević
- Department of Physics, Stockholm University, 10691 Stockholm, Sweden
| | - Miroslav Ježek
- Department of Optics, Faculty of Science, Palacký University, 17. listopadu 12, 77146 Olomouc, Czechia
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37
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Somhorst FHB, van der Meer R, Correa Anguita M, Schadow R, Snijders HJ, de Goede M, Kassenberg B, Venderbosch P, Taballione C, Epping JP, van den Vlekkert HH, Timmerhuis J, Bulmer JFF, Lugani J, Walmsley IA, Pinkse PWH, Eisert J, Walk N, Renema JJ. Quantum simulation of thermodynamics in an integrated quantum photonic processor. Nat Commun 2023; 14:3895. [PMID: 37393275 DOI: 10.1038/s41467-023-38413-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 05/02/2023] [Indexed: 07/03/2023] Open
Abstract
One of the core questions of quantum physics is how to reconcile the unitary evolution of quantum states, which is information-preserving and time-reversible, with evolution following the second law of thermodynamics, which, in general, is neither. The resolution to this paradox is to recognize that global unitary evolution of a multi-partite quantum state causes the state of local subsystems to evolve towards maximum-entropy states. In this work, we experimentally demonstrate this effect in linear quantum optics by simultaneously showing the convergence of local quantum states to a generalized Gibbs ensemble constituting a maximum-entropy state under precisely controlled conditions, while introducing an efficient certification method to demonstrate that the state retains global purity. Our quantum states are manipulated by a programmable integrated quantum photonic processor, which simulates arbitrary non-interacting Hamiltonians, demonstrating the universality of this phenomenon. Our results show the potential of photonic devices for quantum simulations involving non-Gaussian states.
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Affiliation(s)
- F H B Somhorst
- MESA+ Institute for Nanotechnology, University of Twente, P. O. box 217, 7500 AE, Enschede, The Netherlands
| | - R van der Meer
- MESA+ Institute for Nanotechnology, University of Twente, P. O. box 217, 7500 AE, Enschede, The Netherlands
| | - M Correa Anguita
- MESA+ Institute for Nanotechnology, University of Twente, P. O. box 217, 7500 AE, Enschede, The Netherlands
| | - R Schadow
- Dahlem Center for Complex Quantum Systems, Freie Universität Berlin, 14195, Berlin, Germany
| | - H J Snijders
- QuiX Quantum B.V., Hengelosestraat 500, 7521 AN, Enschede, The Netherlands
| | - M de Goede
- QuiX Quantum B.V., Hengelosestraat 500, 7521 AN, Enschede, The Netherlands
| | - B Kassenberg
- QuiX Quantum B.V., Hengelosestraat 500, 7521 AN, Enschede, The Netherlands
| | - P Venderbosch
- QuiX Quantum B.V., Hengelosestraat 500, 7521 AN, Enschede, The Netherlands
| | - C Taballione
- QuiX Quantum B.V., Hengelosestraat 500, 7521 AN, Enschede, The Netherlands
| | - J P Epping
- QuiX Quantum B.V., Hengelosestraat 500, 7521 AN, Enschede, The Netherlands
| | | | - J Timmerhuis
- MESA+ Institute for Nanotechnology, University of Twente, P. O. box 217, 7500 AE, Enschede, The Netherlands
| | - J F F Bulmer
- Quantum Engineering Technology Labs, University of Bristol, Bristol, UK
| | - J Lugani
- Center for Sensors, Instrumentation and Cyber Physical System Engineering, IIT Delhi, New Delhi, 110 016, India
| | - I A Walmsley
- Department of Physics, Imperial College London, Prince Consort Rd., London, SW7 2AZ, UK
- Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU, UK
| | - P W H Pinkse
- MESA+ Institute for Nanotechnology, University of Twente, P. O. box 217, 7500 AE, Enschede, The Netherlands
| | - J Eisert
- Dahlem Center for Complex Quantum Systems, Freie Universität Berlin, 14195, Berlin, Germany.
- Helmholtz-Zentrum Berlin für Materialien und Energie, 14109, Berlin, Germany.
- Fraunhofer Heinrich Hertz Institute, 10587, Berlin, Germany.
| | - N Walk
- Dahlem Center for Complex Quantum Systems, Freie Universität Berlin, 14195, Berlin, Germany.
| | - J J Renema
- MESA+ Institute for Nanotechnology, University of Twente, P. O. box 217, 7500 AE, Enschede, The Netherlands.
- QuiX Quantum B.V., Hengelosestraat 500, 7521 AN, Enschede, The Netherlands.
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38
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Hales J, Bajpai U, Liu T, Baykusheva DR, Li M, Mitrano M, Wang Y. Witnessing light-driven entanglement using time-resolved resonant inelastic X-ray scattering. Nat Commun 2023; 14:3512. [PMID: 37316515 DOI: 10.1038/s41467-023-38540-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2022] [Accepted: 05/03/2023] [Indexed: 06/16/2023] Open
Abstract
Characterizing and controlling entanglement in quantum materials is crucial for the development of next-generation quantum technologies. However, defining a quantifiable figure of merit for entanglement in macroscopic solids is theoretically and experimentally challenging. At equilibrium the presence of entanglement can be diagnosed by extracting entanglement witnesses from spectroscopic observables and a nonequilibrium extension of this method could lead to the discovery of novel dynamical phenomena. Here, we propose a systematic approach to quantify the time-dependent quantum Fisher information and entanglement depth of transient states of quantum materials with time-resolved resonant inelastic x-ray scattering. Using a quarter-filled extended Hubbard model as an example, we benchmark the efficiency of this approach and predict a light-enhanced many-body entanglement due to the proximity to a phase boundary. Our work sets the stage for experimentally witnessing and controlling entanglement in light-driven quantum materials via ultrafast spectroscopic measurements.
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Affiliation(s)
- Jordyn Hales
- Department of Physics and Astronomy, Clemson University, Clemson, SC, 29634, USA
| | - Utkarsh Bajpai
- Department of Physics and Astronomy, Clemson University, Clemson, SC, 29634, USA
| | - Tongtong Liu
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | | | - Mingda Li
- Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Matteo Mitrano
- Department of Physics, Harvard University, Cambridge, MA, 02138, USA.
| | - Yao Wang
- Department of Physics and Astronomy, Clemson University, Clemson, SC, 29634, USA.
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39
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Martin LS, Zhou H, Leitao NT, Maskara N, Makarova O, Gao H, Zhu QZ, Park M, Tyler M, Park H, Choi S, Lukin MD. Controlling Local Thermalization Dynamics in a Floquet-Engineered Dipolar Ensemble. PHYSICAL REVIEW LETTERS 2023; 130:210403. [PMID: 37295118 DOI: 10.1103/physrevlett.130.210403] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 05/03/2023] [Indexed: 06/12/2023]
Abstract
Understanding the microscopic mechanisms of thermalization in closed quantum systems is among the key challenges in modern quantum many-body physics. We demonstrate a method to probe local thermalization in a large-scale many-body system by exploiting its inherent disorder and use this to uncover the thermalization mechanisms in a three-dimensional, dipolar-interacting spin system with tunable interactions. Utilizing advanced Hamiltonian engineering techniques to explore a range of spin Hamiltonians, we observe a striking change in the characteristic shape and timescale of local correlation decay as we vary the engineered exchange anisotropy. We show that these observations originate from the system's intrinsic many-body dynamics and reveal the signatures of conservation laws within localized clusters of spins, which do not readily manifest using global probes. Our method provides an exquisite lens into the tunable nature of local thermalization dynamics and enables detailed studies of scrambling, thermalization, and hydrodynamics in strongly interacting quantum systems.
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Affiliation(s)
- Leigh S Martin
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Hengyun Zhou
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Nathaniel T Leitao
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Nishad Maskara
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Oksana Makarova
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Haoyang Gao
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Qian-Ze Zhu
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Mincheol Park
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Matthew Tyler
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Hongkun Park
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Soonwon Choi
- Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Mikhail D Lukin
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
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40
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Šafránek D, Rosa D, Binder FC. Work Extraction from Unknown Quantum Sources. PHYSICAL REVIEW LETTERS 2023; 130:210401. [PMID: 37295083 DOI: 10.1103/physrevlett.130.210401] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 04/07/2023] [Indexed: 06/12/2023]
Abstract
Energy extraction is a central task in thermodynamics. In quantum physics, ergotropy measures the amount of work extractable under cyclic Hamiltonian control. As its full extraction requires perfect knowledge of the initial state, however, it does not characterize the work value of unknown or untrusted quantum sources. Fully characterizing such sources would require quantum tomography, which is prohibitively costly in experiments due to the exponential growth of required measurements and operational limitations. Here, we therefore derive a new notion of ergotropy applicable when nothing is known about the quantum states produced by the source, apart from what can be learned by performing only a single type of coarse-grained measurement. We find that in this case the extracted work is defined by the Boltzmann and observational entropy in cases where the measurement outcomes are, or are not, used in the work extraction, respectively. This notion of ergotropy represents a realistic measure of extractable work, which can be used as the relevant figure of merit to characterize a quantum battery.
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Affiliation(s)
- Dominik Šafránek
- Center for Theoretical Physics of Complex Systems, Institute for Basic Science (IBS), Daejeon - 34126, Korea
| | - Dario Rosa
- Center for Theoretical Physics of Complex Systems, Institute for Basic Science (IBS), Daejeon - 34126, Korea
- Basic Science Program, Korea University of Science and Technology (UST), Daejeon-34113, Korea
| | - Felix C Binder
- School of Physics, Trinity College Dublin, Dublin 2, Ireland
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41
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Ray S, Alsing PM, Cafaro C, Jacinto HS. A Differential-Geometric Approach to Quantum Ignorance Consistent with Entropic Properties of Statistical Mechanics. ENTROPY (BASEL, SWITZERLAND) 2023; 25:e25050788. [PMID: 37238543 DOI: 10.3390/e25050788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 05/03/2023] [Accepted: 05/07/2023] [Indexed: 05/28/2023]
Abstract
In this paper, we construct the metric tensor and volume for the manifold of purifications associated with an arbitrary reduced density operator ρS. We also define a quantum coarse-graining (CG) to study the volume where macrostates are the manifolds of purifications, which we call surfaces of ignorance (SOI), and microstates are the purifications of ρS. In this context, the volume functions as a multiplicity of the macrostates that quantifies the amount of information missing from ρS. Using examples where the SOI are generated using representations of SU(2), SO(3), and SO(N), we show two features of the CG: (1) A system beginning in an atypical macrostate of smaller volume evolves to macrostates of greater volume until it reaches the equilibrium macrostate in a process in which the system and environment become strictly more entangled, and (2) the equilibrium macrostate takes up the vast majority of the coarse-grained space especially as the dimension of the total system becomes large. Here, the equilibrium macrostate corresponds to a maximum entanglement between the system and the environment. To demonstrate feature (1) for the examples considered, we show that the volume behaves like the von Neumann entropy in that it is zero for pure states, maximal for maximally mixed states, and is a concave function with respect to the purity of ρS. These two features are essential to typicality arguments regarding thermalization and Boltzmann's original CG.
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Affiliation(s)
- Shannon Ray
- Air Force Research Laboratory, Rome, NY 13441, USA
- Griffiss Institute, Rome, NY 13441, USA
| | | | - Carlo Cafaro
- Department of Mathematics and Physics, SUNY Polytechnic Institute, Albany, NY 12203, USA
| | - H S Jacinto
- Air Force Research Laboratory, Rome, NY 13441, USA
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42
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Bauer NP, Budich JC, Trauzettel B, Calzona A. Quench-Probe Setup as Analyzer of Fractionalized Entanglement Spreading. PHYSICAL REVIEW LETTERS 2023; 130:190401. [PMID: 37243652 DOI: 10.1103/physrevlett.130.190401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 04/11/2023] [Indexed: 05/29/2023]
Abstract
We propose a novel spatially inhomogeneous setup for revealing quench-induced fractionalized excitations in entanglement dynamics. In this quench-probe setting, the region undergoing a quantum quench is tunnel coupled to a static region, the probe. Subsequently, the time-dependent entanglement signatures of a tunable subset of excitations propagating to the probe are monitored by energy selectivity. We exemplify the power of this generic approach by identifying a unique dynamical signature associated with the presence of an isolated Majorana zero mode in the postquench Hamiltonian. In this case excitations emitted from the topological part of the system give rise to a fractionalized jump of log(2)/2 in the entanglement entropy of the probe. This dynamical effect is highly sensitive to the localized nature of the Majorana zero mode, but does not require the preparation of a topological initial state.
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Affiliation(s)
- Nicolas P Bauer
- Institute of Theoretical Physics and Astrophysics, University of Würzburg, 97074 Würzburg, Germany
- Würzburg-Dresden Cluster of Excellence ct.qmat, Germany
| | - Jan Carl Budich
- Würzburg-Dresden Cluster of Excellence ct.qmat, Germany
- Institute of Theoretical Physics, Technische Universität Dresden, 01062 Dresden, Germany
| | - Björn Trauzettel
- Institute of Theoretical Physics and Astrophysics, University of Würzburg, 97074 Würzburg, Germany
- Würzburg-Dresden Cluster of Excellence ct.qmat, Germany
| | - Alessio Calzona
- Institute of Theoretical Physics and Astrophysics, University of Würzburg, 97074 Würzburg, Germany
- Würzburg-Dresden Cluster of Excellence ct.qmat, Germany
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43
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Liu T, Liu S, Li H, Li H, Huang K, Xiang Z, Song X, Xu K, Zheng D, Fan H. Observation of entanglement transition of pseudo-random mixed states. Nat Commun 2023; 14:1971. [PMID: 37031244 PMCID: PMC10082798 DOI: 10.1038/s41467-023-37511-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 03/17/2023] [Indexed: 04/10/2023] Open
Abstract
Random quantum states serve as a powerful tool in various scientific fields, including quantum supremacy and black hole physics. It has been theoretically predicted that entanglement transitions may happen for different partitions of multipartite random quantum states; however, the experimental observation of these transitions is still absent. Here, we experimentally demonstrate the entanglement transitions witnessed by negativity on a fully connected superconducting processor. We apply parallel entangling operations, that significantly decrease the depth of the pseudo-random circuits, to generate pseudo-random pure states of up to 15 qubits. By quantum state tomography of the reduced density matrix of six qubits, we measure the negativity spectra. Then, by changing the sizes of the environment and subsystems, we observe the entanglement transitions that are directly identified by logarithmic entanglement negativities based on the negativity spectra. In addition, we characterize the randomness of our circuits by measuring the distance between the distribution of output bit-string probabilities and the Porter-Thomas distribution. Our results show that superconducting processors with all-to-all connectivity constitute a promising platform for generating random states and understanding the entanglement structure of multipartite quantum systems.
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Affiliation(s)
- Tong Liu
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Shang Liu
- Kavli Institute for Theoretical Physics, University of California, Santa Barbara, CA, 93106, USA
| | - Hekang Li
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Hao Li
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Kaixuan Huang
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Beijing Academy of Quantum Information Sciences, Beijing, 100193, China
| | - Zhongcheng Xiang
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
- Beijing Academy of Quantum Information Sciences, Beijing, 100193, China
- Hefei National Laboratory, Hefei, 230088, China
- CAS Center of Excellence for Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing, 100190, China
- Songshan Lake Materials Laboratory, Dongguan, 523808, Guangdong, China
| | - Xiaohui Song
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
- Beijing Academy of Quantum Information Sciences, Beijing, 100193, China
- Hefei National Laboratory, Hefei, 230088, China
- CAS Center of Excellence for Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing, 100190, China
- Songshan Lake Materials Laboratory, Dongguan, 523808, Guangdong, China
| | - Kai Xu
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China.
- Beijing Academy of Quantum Information Sciences, Beijing, 100193, China.
- Hefei National Laboratory, Hefei, 230088, China.
- CAS Center of Excellence for Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing, 100190, China.
- Songshan Lake Materials Laboratory, Dongguan, 523808, Guangdong, China.
| | - Dongning Zheng
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China.
- Beijing Academy of Quantum Information Sciences, Beijing, 100193, China.
- Hefei National Laboratory, Hefei, 230088, China.
- CAS Center of Excellence for Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing, 100190, China.
- Songshan Lake Materials Laboratory, Dongguan, 523808, Guangdong, China.
| | - Heng Fan
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China.
- Beijing Academy of Quantum Information Sciences, Beijing, 100193, China.
- Hefei National Laboratory, Hefei, 230088, China.
- CAS Center of Excellence for Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing, 100190, China.
- Songshan Lake Materials Laboratory, Dongguan, 523808, Guangdong, China.
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44
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Burke PC, Haque M. Entropy and temperature in finite isolated quantum systems. Phys Rev E 2023; 107:034125. [PMID: 37072955 DOI: 10.1103/physreve.107.034125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 03/01/2023] [Indexed: 04/20/2023]
Abstract
We investigate how the temperature calculated from the microcanonical entropy compares with the canonical temperature for finite isolated quantum systems. We concentrate on systems with sizes that make them accessible to numerical exact diagonalization. We thus characterize the deviations from ensemble equivalence at finite sizes. We describe multiple ways to compute the microcanonical entropy and present numerical results for the entropy and temperature computed in these various ways. We show that using an energy window whose width has a particular energy dependence results in a temperature with minimal deviations from the canonical temperature.
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Affiliation(s)
- Phillip C Burke
- Department of Theoretical Physics, Maynooth University, Maynooth, W23 F2H6 Kildare, Ireland
| | - Masudul Haque
- Department of Theoretical Physics, Maynooth University, Maynooth, W23 F2H6 Kildare, Ireland
- Institut für Theoretische Physik, Technische Universität Dresden, 01062 Dresden, Germany
- Max-Planck Institute for the Physics of Complex Systems, 01187 Dresden, Germany
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45
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Brunner E, Pausch L, Carnio EG, Dufour G, Rodríguez A, Buchleitner A. Many-Body Interference at the Onset of Chaos. PHYSICAL REVIEW LETTERS 2023; 130:080401. [PMID: 36898099 DOI: 10.1103/physrevlett.130.080401] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 01/16/2023] [Accepted: 01/27/2023] [Indexed: 06/18/2023]
Abstract
We unveil the signature of many-body interference across dynamical regimes of the Bose-Hubbard model. Increasing the particles' indistinguishability enhances the temporal fluctuations of few-body observables, with a dramatic amplification at the onset of quantum chaos. By resolving the exchange symmetries of partially distinguishable particles, we explain this amplification as the fingerprint of the initial state's coherences in the eigenbasis.
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Affiliation(s)
- Eric Brunner
- Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Straße 3, 79104, Freiburg, Germany
- EUCOR Centre for Quantum Science and Quantum Computing, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Straße 3, 79104, Freiburg, Germany
| | - Lukas Pausch
- Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Straße 3, 79104, Freiburg, Germany
- EUCOR Centre for Quantum Science and Quantum Computing, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Straße 3, 79104, Freiburg, Germany
| | - Edoardo G Carnio
- Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Straße 3, 79104, Freiburg, Germany
- EUCOR Centre for Quantum Science and Quantum Computing, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Straße 3, 79104, Freiburg, Germany
| | - Gabriel Dufour
- Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Straße 3, 79104, Freiburg, Germany
- EUCOR Centre for Quantum Science and Quantum Computing, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Straße 3, 79104, Freiburg, Germany
| | - Alberto Rodríguez
- Departamento de Física Fundamental, Universidad de Salamanca, E-37008 Salamanca, Spain
- Instituto Universitario de Física Fundamental y Matemáticas (IUFFyM), Universidad de Salamanca, E-37008 Salamanca, Spain
| | - Andreas Buchleitner
- Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Straße 3, 79104, Freiburg, Germany
- EUCOR Centre for Quantum Science and Quantum Computing, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Straße 3, 79104, Freiburg, Germany
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46
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Burke PC, Nakerst G, Haque M. Assigning temperatures to eigenstates. Phys Rev E 2023; 107:024102. [PMID: 36932575 DOI: 10.1103/physreve.107.024102] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 01/17/2023] [Indexed: 06/18/2023]
Abstract
In the study of thermalization in finite isolated quantum systems, an inescapable issue is the definition of temperature. We examine and compare different possible ways of assigning temperatures to energies or equivalently to eigenstates in such systems. A commonly used assignment of temperature in the context of thermalization is based on the canonical energy-temperature relationship, which depends only on energy eigenvalues and not on the structure of eigenstates. For eigenstates, we consider defining temperature by minimizing the distance between (full or reduced) eigenstate density matrices and canonical density matrices. We show that for full eigenstates, the minimizing temperature depends on the distance measure chosen and matches the canonical temperature for the trace distance; however, the two matrices are not close. With reduced density matrices, the minimizing temperature has fluctuations that scale with subsystem and system size but appears to be independent of distance measure. In particular limits, the two matrices become equivalent while the temperature tends to the canonical temperature.
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Affiliation(s)
- Phillip C Burke
- Department of Theoretical Physics, Maynooth University, Maynooth, Kildare, Ireland
| | - Goran Nakerst
- Department of Theoretical Physics, Maynooth University, Maynooth, Kildare, Ireland
- Institut für Theoretische Physik, Technische Universität Dresden, 01062 Dresden, Germany
| | - Masudul Haque
- Department of Theoretical Physics, Maynooth University, Maynooth, Kildare, Ireland
- Institut für Theoretische Physik, Technische Universität Dresden, 01062 Dresden, Germany
- Max-Planck Institute for the Physics of Complex Systems, Dresden, Germany
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47
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Pulikkottil JJ, Lakshminarayan A, Srivastava SCL, Kieler MFI, Bäcker A, Tomsovic S. Quantum coherence controls the nature of equilibration and thermalization in coupled chaotic systems. Phys Rev E 2023; 107:024124. [PMID: 36932552 DOI: 10.1103/physreve.107.024124] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 01/09/2023] [Indexed: 06/18/2023]
Abstract
A bipartite system whose subsystems are fully quantum chaotic and coupled by a perturbative interaction with a tunable strength is a paradigmatic model for investigating how isolated quantum systems relax toward an equilibrium. It is found that quantum coherence of the initial product states in the energy eigenbasis of the subsystems-quantified by the off-diagonal elements of the subsystem density matrices-can be viewed as a resource for equilibration and thermalization as manifested by the entanglement generated. Results are given for four distinct perturbation strength regimes, the ultraweak, weak, intermediate, and strong regimes. For each, three types of tensor product states are considered for the initial state: uniform superpositions, random superpositions, and individual subsystem eigenstates. A universal timescale is identified involving the interaction strength parameter. In particular, maximally coherent initial product states (a form of uniform superpositions) thermalize under time evolution for any perturbation strength in spite of the fact that in the ultraweak perturbative regime the underlying eigenstates of the system have a tensor product structure and are not at all thermal-like; though the time taken to thermalize tends to infinity as the interaction vanishes. Moreover, it is shown that in the ultraweak regime the initial entanglement growth of the system whose initial states are maximally coherent is quadratic-in-time, in contrast to the widely observed linear behavior.
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Affiliation(s)
- Jethin J Pulikkottil
- Department of Physics and Astronomy, Washington State University, Pullman, Washington 99164-2814, USA
| | - Arul Lakshminarayan
- Department of Physics, Indian Institute of Technology Madras, Chennai 600036, India
| | - Shashi C L Srivastava
- Variable Energy Cyclotron Centre, 1/AF Bidhannagar, Kolkata 700064, India
- Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai-400094, India
| | - Maximilian F I Kieler
- Technische Universität Dresden, Institut für Theoretische Physik and Center for Dynamics, 01062 Dresden, Germany
| | - Arnd Bäcker
- Technische Universität Dresden, Institut für Theoretische Physik and Center for Dynamics, 01062 Dresden, Germany
| | - Steven Tomsovic
- Department of Physics and Astronomy, Washington State University, Pullman, Washington 99164-2814, USA
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48
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Yurovsky VA. Exploring Integrability-Chaos Transition with a Sequence of Independent Perturbations. PHYSICAL REVIEW LETTERS 2023; 130:020404. [PMID: 36706418 DOI: 10.1103/physrevlett.130.020404] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Accepted: 12/20/2022] [Indexed: 06/18/2023]
Abstract
A gas of interacting particles is a paradigmatic example of chaotic systems. It is shown here that, even if all but one particle are fixed in generic positions, the excited states of the moving particle are chaotic. They are characterized by the number of principal components (NPC)-the number of integrable system eigenstates involved into the nonintegrable one, which increases linearly with the number of strong scatterers. This rule is a particular case of the general effect of an additional perturbation on the system chaotic properties. The perturbation independence criteria supposing the system chaoticity increase are derived here as well. The effect can be observed in experiments with photons or cold atoms as the decay of observable fluctuation variance, which is inversely proportional to NPC and, therefore, to the number of scatterers. This decay indicates that the eigenstate thermalization is approached. The results are confirmed by numerical calculations for a harmonic waveguide with zero-range scatterers along its axis.
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49
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Noh JD. Eigenstate thermalization hypothesis in two-dimensional XXZ model with or without SU(2) symmetry. Phys Rev E 2023; 107:014130. [PMID: 36797888 DOI: 10.1103/physreve.107.014130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 01/06/2023] [Indexed: 06/18/2023]
Abstract
We investigate the eigenstate thermalization properties of the spin-1/2 XXZ model in two-dimensional rectangular lattices of size L_{1}×L_{2} under periodic boundary conditions. Exploiting the symmetry property, we can perform an exact diagonalization study of the energy eigenvalues up to system size 4×7 and of the energy eigenstates up to 4×6. Numerical analysis of the Hamiltonian eigenvalue spectrum and matrix elements of an observable in the Hamiltonian eigenstate basis supports that the two-dimensional XXZ model follows the eigenstate thermalization hypothesis. When the spin interaction is isotropic, the XXZ model Hamiltonian conserves the total spin and has SU(2) symmetry. We show that the eigenstate thermalization hypothesis is still valid within each subspace where the total spin is a good quantum number.
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Affiliation(s)
- Jae Dong Noh
- Department of Physics, University of Seoul, Seoul 02504, Korea
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50
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Choi J, Shaw AL, Madjarov IS, Xie X, Finkelstein R, Covey JP, Cotler JS, Mark DK, Huang HY, Kale A, Pichler H, Brandão FGSL, Choi S, Endres M. Preparing random states and benchmarking with many-body quantum chaos. Nature 2023; 613:468-473. [PMID: 36653567 DOI: 10.1038/s41586-022-05442-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 10/13/2022] [Indexed: 01/19/2023]
Abstract
Producing quantum states at random has become increasingly important in modern quantum science, with applications being both theoretical and practical. In particular, ensembles of such randomly distributed, but pure, quantum states underlie our understanding of complexity in quantum circuits1 and black holes2, and have been used for benchmarking quantum devices3,4 in tests of quantum advantage5,6. However, creating random ensembles has necessitated a high degree of spatio-temporal control7-12 placing such studies out of reach for a wide class of quantum systems. Here we solve this problem by predicting and experimentally observing the emergence of random state ensembles naturally under time-independent Hamiltonian dynamics, which we use to implement an efficient, widely applicable benchmarking protocol. The observed random ensembles emerge from projective measurements and are intimately linked to universal correlations built up between subsystems of a larger quantum system, offering new insights into quantum thermalization13. Predicated on this discovery, we develop a fidelity estimation scheme, which we demonstrate for a Rydberg quantum simulator with up to 25 atoms using fewer than 104 experimental samples. This method has broad applicability, as we demonstrate for Hamiltonian parameter estimation, target-state generation benchmarking, and comparison of analogue and digital quantum devices. Our work has implications for understanding randomness in quantum dynamics14 and enables applications of this concept in a much wider context4,5,9,10,15-20.
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Affiliation(s)
- Joonhee Choi
- California Institute of Technology, Pasadena, CA, USA
| | - Adam L Shaw
- California Institute of Technology, Pasadena, CA, USA
| | | | - Xin Xie
- California Institute of Technology, Pasadena, CA, USA
| | | | - Jacob P Covey
- California Institute of Technology, Pasadena, CA, USA.,Department of Physics, The University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | | | - Daniel K Mark
- Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | | | | | - Hannes Pichler
- Institute for Theoretical Physics, University of Innsbruck, Innsbruck, Austria.,Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, Innsbruck, Austria
| | | | - Soonwon Choi
- Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, MA, USA. .,Department of Physics, University of California, Berkeley, CA, USA.
| | - Manuel Endres
- California Institute of Technology, Pasadena, CA, USA.
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