1
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Khan G, Soomro H, Baig MU, Javed I, Chaudhry AZ. A generalized framework for the quantum Zeno and anti-Zeno effects in the strong coupling regime. Sci Rep 2022; 12:18652. [PMID: 36333438 PMCID: PMC9636234 DOI: 10.1038/s41598-022-23421-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 10/31/2022] [Indexed: 11/06/2022] Open
Abstract
It is well known that repeated projective measurements can either slow down (the Zeno effect) or speed up (the anti-Zeno effect) quantum evolution. Until now, studies of these effects for a two-level system interacting with its environment have focused on repeatedly preparing the excited state via projective measurements. In this paper, we consider the repeated preparation of an arbitrary state of a two-level system that is interacting strongly with an environment of harmonic oscillators. To handle the strong interaction, we perform a polaron transformation and then use a perturbative approach to calculate the decay rates for the system. Upon calculating the decay rates, we discover that there is a transition in their qualitative behaviors as the state being repeatedly prepared continuously moves away from the excited state and toward a uniform superposition of the ground and excited states. Our results should be useful for the quantum control of a two-level system interacting with its environment.
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2
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Klco N, Roggero A, Savage MJ. Standard model physics and the digital quantum revolution: thoughts about the interface. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2022; 85:064301. [PMID: 35213853 DOI: 10.1088/1361-6633/ac58a4] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Accepted: 02/25/2022] [Indexed: 06/14/2023]
Abstract
Advances in isolating, controlling and entangling quantum systems are transforming what was once a curious feature of quantum mechanics into a vehicle for disruptive scientific and technological progress. Pursuing the vision articulated by Feynman, a concerted effort across many areas of research and development is introducing prototypical digital quantum devices into the computing ecosystem available to domain scientists. Through interactions with these early quantum devices, the abstract vision of exploring classically-intractable quantum systems is evolving toward becoming a tangible reality. Beyond catalyzing these technological advances, entanglement is enabling parallel progress as a diagnostic for quantum correlations and as an organizational tool, both guiding improved understanding of quantum many-body systems and quantum field theories defining and emerging from the standard model. From the perspective of three domain science theorists, this article compilesthoughts about the interfaceon entanglement, complexity, and quantum simulation in an effort to contextualize recent NISQ-era progress with the scientific objectives of nuclear and high-energy physics.
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Affiliation(s)
- Natalie Klco
- Institute for Quantum Information and Matter and Walter Burke Institute for Theoretical Physics, California Institute of Technology, Pasadena CA 91125, United States of America
| | - Alessandro Roggero
- InQubator for Quantum Simulation (IQuS), Department of Physics, University of Washington, Seattle, WA 98195, United States of America
| | - Martin J Savage
- InQubator for Quantum Simulation (IQuS), Department of Physics, University of Washington, Seattle, WA 98195, United States of America
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3
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Zohar E. Quantum simulation of lattice gauge theories in more than one space dimension-requirements, challenges and methods. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2022; 380:20210069. [PMID: 34923840 PMCID: PMC8886423 DOI: 10.1098/rsta.2021.0069] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 08/18/2021] [Indexed: 05/17/2023]
Abstract
Over recent years, the relatively young field of quantum simulation of lattice gauge theories, aiming at implementing simulators of gauge theories with quantum platforms, has gone through a rapid development process. Nowadays, it is not only of interest to the quantum information and technology communities. It is also seen as a valid tool for tackling hard, non-perturbative gauge theory problems by particle and nuclear physicists. Along the theoretical progress, nowadays more and more experiments implementing such simulators are being reported, manifesting beautiful results, but mostly on [Formula: see text] dimensional physics. In this article, we review the essential ingredients and requirements of lattice gauge theories in more dimensions and discuss their meanings, the challenges they pose and how they could be dealt with, potentially aiming at the next steps of this field towards simulating challenging physical problems in analogue, or analogue-digital ways. This article is part of the theme issue 'Quantum technologies in particle physics'.
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Affiliation(s)
- Erez Zohar
- Racah Institute of Physics, The Hebrew University of Jerusalem, Givat Ram, Jerusalem 91904, Israel
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4
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Aidelsburger M, Barbiero L, Bermudez A, Chanda T, Dauphin A, González-Cuadra D, Grzybowski PR, Hands S, Jendrzejewski F, Jünemann J, Juzeliūnas G, Kasper V, Piga A, Ran SJ, Rizzi M, Sierra G, Tagliacozzo L, Tirrito E, Zache TV, Zakrzewski J, Zohar E, Lewenstein M. Cold atoms meet lattice gauge theory. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2022; 380:20210064. [PMID: 34923836 PMCID: PMC8685612 DOI: 10.1098/rsta.2021.0064] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 08/23/2021] [Indexed: 05/17/2023]
Abstract
The central idea of this review is to consider quantum field theory models relevant for particle physics and replace the fermionic matter in these models by a bosonic one. This is mostly motivated by the fact that bosons are more 'accessible' and easier to manipulate for experimentalists, but this 'substitution' also leads to new physics and novel phenomena. It allows us to gain new information about among other things confinement and the dynamics of the deconfinement transition. We will thus consider bosons in dynamical lattices corresponding to the bosonic Schwinger or [Formula: see text] Bose-Hubbard models. Another central idea of this review concerns atomic simulators of paradigmatic models of particle physics theory such as the Creutz-Hubbard ladder, or Gross-Neveu-Wilson and Wilson-Hubbard models. This article is not a general review of the rapidly growing field-it reviews activities related to quantum simulations for lattice field theories performed by the Quantum Optics Theory group at ICFO and their collaborators from 19 institutions all over the world. Finally, we will briefly describe our efforts to design experimentally friendly simulators of these and other models relevant for particle physics. This article is part of the theme issue 'Quantum technologies in particle physics'.
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Affiliation(s)
- Monika Aidelsburger
- Fakultät für Physik, Ludwig-Maximilians-Universität München, Munich 80799, Germany
- Munich Center for Quantum Science and Technology (MCQST), München 80799, Germany
| | - Luca Barbiero
- ICFO—Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona 08860, Spain
- Institute for Condensed Matter Physics and Complex Systems, DISAT, Politecnico di Torino, I-10129 Torino, Italy
| | - Alejandro Bermudez
- Departamento de Física Teorica, Universidad Complutense, Madrid 28040, Spain
| | - Titas Chanda
- Institute of Theoretical Physics, Jagiellonian University in Kraków, Kraków 30-348, Poland
- The Abdus Salam International Centre for Theoretical Physics (ICTP), Strada Costiera 11, 34151 Trieste, Italy
| | - Alexandre Dauphin
- ICFO—Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona 08860, Spain
| | - Daniel González-Cuadra
- ICFO—Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona 08860, Spain
| | - Przemysław R. Grzybowski
- Institute of Spintronics and Quantum Information, Faculty of Physics, Adam Mickiewicz University in Poznań, Poznań, Poland
| | - Simon Hands
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea SA28PP, UK
- Department of Mathematical Sciences, University of Liverpool, Liverpool L69 3BX, UK
| | - Fred Jendrzejewski
- Kirchhoff-Institut für Physik, Universität Heidelberg, Heidelberg 69120, Germany
| | - Johannes Jünemann
- Institut für Physik, Johannes Gutenberg-Universität, Mainz 55128, Germany
| | - Gediminas Juzeliūnas
- Institute of Theoretical Physics and Astronomy, Vilnius University, Vilnius 10257, Lithuania
| | - Valentin Kasper
- ICFO—Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona 08860, Spain
| | - Angelo Piga
- ICFO—Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona 08860, Spain
- Departament of Chemical Engineering, Universitat Rovira I Virgili, 43007, Tarragona, Catalonia, Spain
| | - Shi-Ju Ran
- Department of Physics, Capital Normal University, Beijing 100048, People’s Republic of China
| | - Matteo Rizzi
- Forschungszentrum Jülich GmbH, Institute of Quantum Control, Peter Grünberg Institut (PGI-8), Jülich 52425, Germany
- Institute for Theoretical Physics, University of Cologne, Köln 50937, Germany
| | - Germán Sierra
- Instituto de Física Teórica, UAM/CSIC, Universidad Autònoma de Madrid, Madrid, Spain
| | - Luca Tagliacozzo
- Departament de Física Quàntica i Astrofísica and Institut de Ciències del Cosmos (ICCUB), Universitat de Barcelona, Barcelona, Catalonia 08028, Spain
| | - Emanuele Tirrito
- International School for Advanced Studies (SISSA), Trieste 34136, Italy
| | - Torsten V. Zache
- Center for Quantum Physics, University of Innsbruck, Innsbruck 6020, Austria
- Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, Innsbruck 6020, Austria
| | - Jakub Zakrzewski
- Institute of Theoretical Physics, Jagiellonian University in Kraków, Kraków 30-348, Poland
| | - Erez Zohar
- Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Maciej Lewenstein
- ICFO—Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona 08860, Spain
- ICREA, Passeig Lluis Companys 23, Barcelona 08010, Spain
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5
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Armon T, Ashkenazi S, García-Moreno G, González-Tudela A, Zohar E. Photon-Mediated Stroboscopic Quantum Simulation of a Z_{2} Lattice Gauge Theory. PHYSICAL REVIEW LETTERS 2021; 127:250501. [PMID: 35029424 DOI: 10.1103/physrevlett.127.250501] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 11/15/2021] [Indexed: 06/14/2023]
Abstract
Quantum simulation of lattice gauge theories, aiming at tackling nonperturbative particle and condensed matter physics, has recently received a lot of interest and attention, resulting in many theoretical proposals as well as several experimental implementations. One of the current challenges is to go beyond 1+1 dimensions, where four-body (plaquette) interactions, not contained naturally in quantum simulating devices, appear. In this Letter, we propose a method to obtain them based on a combination of stroboscopic optical atomic control and the nonlocal photon-mediated interactions appearing in nanophotonic or cavity QED setups. We illustrate the method for a Z_{2} lattice gauge theory. We also show how to prepare the ground state and measure Wilson loops using state-of-the-art techniques in atomic physics.
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Affiliation(s)
- Tsafrir Armon
- Racah Institute of Physics, Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Shachar Ashkenazi
- Racah Institute of Physics, Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Gerardo García-Moreno
- Institute of Fundamental Physics IFF-CSIC, Calle Serrano 113b, 28006 Madrid, Spain, Departamento de Física Teórica and IPARCOS, Universidad Complutense de Madrid, 28040 Madrid, Spain, and Instituto de Astrofísica de Andalucía (IAA-CSIC), Glorieta de la Astronomía, 18008 Granada, Spain
| | | | - Erez Zohar
- Racah Institute of Physics, Hebrew University of Jerusalem, Jerusalem 91904, Israel
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6
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Atas YY, Zhang J, Lewis R, Jahanpour A, Haase JF, Muschik CA. SU(2) hadrons on a quantum computer via a variational approach. Nat Commun 2021; 12:6499. [PMID: 34764262 PMCID: PMC8586147 DOI: 10.1038/s41467-021-26825-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 10/13/2021] [Indexed: 11/24/2022] Open
Abstract
Quantum computers have the potential to create important new opportunities for ongoing essential research on gauge theories. They can provide simulations that are unattainable on classical computers such as sign-problem afflicted models or time evolutions. In this work, we variationally prepare the low-lying eigenstates of a non-Abelian gauge theory with dynamically coupled matter on a quantum computer. This enables the observation of hadrons and the calculation of their associated masses. The SU(2) gauge group considered here represents an important first step towards ultimately studying quantum chromodynamics, the theory that describes the properties of protons, neutrons and other hadrons. Our calculations on an IBM superconducting platform utilize a variational quantum eigensolver to study both meson and baryon states, hadrons which have never been seen in a non-Abelian simulation on a quantum computer. We develop a hybrid resource-efficient approach by combining classical and quantum computing, that not only allows the study of an SU(2) gauge theory with dynamical matter fields on present-day quantum hardware, but further lays out the premises for future quantum simulations that will address currently unanswered questions in particle and nuclear physics.
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Affiliation(s)
- Yasar Y Atas
- Institute for Quantum Computing, University of Waterloo, Waterloo, ON, Canada, N2L 3G1.
- Department of Physics & Astronomy, University of Waterloo, Waterloo, ON, Canada, N2L 3G1.
| | - Jinglei Zhang
- Institute for Quantum Computing, University of Waterloo, Waterloo, ON, Canada, N2L 3G1.
- Department of Physics & Astronomy, University of Waterloo, Waterloo, ON, Canada, N2L 3G1.
| | - Randy Lewis
- Department of Physics and Astronomy, York University, Toronto, ON, Canada, M3J 1P3
| | - Amin Jahanpour
- Institute for Quantum Computing, University of Waterloo, Waterloo, ON, Canada, N2L 3G1
- Department of Physics & Astronomy, University of Waterloo, Waterloo, ON, Canada, N2L 3G1
| | - Jan F Haase
- Institute for Quantum Computing, University of Waterloo, Waterloo, ON, Canada, N2L 3G1.
- Department of Physics & Astronomy, University of Waterloo, Waterloo, ON, Canada, N2L 3G1.
- Institut für Theoretische Physik und IQST, Universität Ulm, Albert-Einstein-Allee 11, D-89069, Ulm, Germany.
| | - Christine A Muschik
- Institute for Quantum Computing, University of Waterloo, Waterloo, ON, Canada, N2L 3G1
- Department of Physics & Astronomy, University of Waterloo, Waterloo, ON, Canada, N2L 3G1
- Perimeter Institute for Theoretical Physics, Waterloo, ON, Canada, N2L 2Y5
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7
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The quantum Zeno and anti-Zeno effects with driving fields in the weak and strong coupling regimes. Sci Rep 2021; 11:1836. [PMID: 33469109 PMCID: PMC7815882 DOI: 10.1038/s41598-021-81424-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Accepted: 01/01/2021] [Indexed: 11/08/2022] Open
Abstract
Repeated measurements in quantum mechanics can freeze (the quantum Zeno effect) or enhance (the quantum anti-Zeno effect) the time-evolution of a quantum system. In this paper, we present a general treatment of the quantum Zeno and anti-Zeno effects for arbitrary driven open quantum systems, assuming only that the system–environment coupling is weak. In particular, we obtain a general expression for the effective decay rate of a two-level system subjected to arbitrary driving fields as well as periodic measurements. We demonstrate that the driving fields change the decay rate, and hence the quantum Zeno and anti-Zeno behavior, both qualitatively and quantitatively. We also extend our results to systems consisting of more than one two-level system, as well as a two-level system strongly coupled to an environment of harmonic oscillators, to further illustrate the non-trivial effect of the driving fields on the quantum Zeno and anti-Zeno effects.
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8
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Zippilli S, Vitali D. Dissipative Engineering of Gaussian Entangled States in Harmonic Lattices with a Single-Site Squeezed Reservoir. PHYSICAL REVIEW LETTERS 2021; 126:020402. [PMID: 33512179 DOI: 10.1103/physrevlett.126.020402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 12/18/2020] [Indexed: 06/12/2023]
Abstract
We study the dissipative preparation of many-body entangled Gaussian states in bosonic lattice models which could be relevant for quantum technology applications. We assume minimal resources, represented by systems described by particle-conserving quadratic Hamiltonians, with a single localized squeezed reservoir. We show that in this way it is possible to prepare, in the steady state, the wide class of pure states which can be generated by applying a generic passive Gaussian transformation on a set of equally squeezed modes. This includes nontrivial multipartite entangled states such as cluster states suitable for measurement-based quantum computation.
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Affiliation(s)
- Stefano Zippilli
- School of Science and Technology, Physics Division, University of Camerino, I-62032 Camerino (MC), Italy
| | - David Vitali
- School of Science and Technology, Physics Division, University of Camerino, I-62032 Camerino (MC), Italy
- INFN, Sezione di Perugia, I-06123 Perugia, Italy
- CNR-INO, L.go Enrico Fermi 6, I-50125 Firenze, Italy
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9
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Halimeh JC, Hauke P. Reliability of Lattice Gauge Theories. PHYSICAL REVIEW LETTERS 2020; 125:030503. [PMID: 32745395 DOI: 10.1103/physrevlett.125.030503] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 05/25/2020] [Accepted: 06/15/2020] [Indexed: 05/29/2023]
Abstract
Currently, there are intense experimental efforts to realize lattice gauge theories in quantum simulators. Except for specific models, however, practical quantum simulators can never be fine-tuned to perfect local gauge invariance. There is thus a strong need for a rigorous understanding of gauge-invariance violation and how to reliably protect against it. As we show through analytic and numerical evidence, in the presence of a gauge invariance-breaking term the gauge violation accumulates only perturbatively at short times before proliferating only at very long times. This proliferation can be suppressed up to infinite times by energetically penalizing processes that drive the dynamics away from the initial gauge-invariant sector. Our results provide a theoretical basis that highlights a surprising robustness of gauge-theory quantum simulators.
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Affiliation(s)
- Jad C Halimeh
- Kirchhoff Institute for Physics, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany
- Institute for Theoretical Physics, Ruprecht-Karls-Universität Heidelberg, Philosophenweg 16, 69120 Heidelberg, Germany
- INO-CNR BEC Center and Department of Physics, University of Trento, Via Sommarive 14, I-38123 Trento, Italy
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Straße 38, 01187 Dresden, Germany
| | - Philipp Hauke
- Kirchhoff Institute for Physics, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany
- Institute for Theoretical Physics, Ruprecht-Karls-Universität Heidelberg, Philosophenweg 16, 69120 Heidelberg, Germany
- INO-CNR BEC Center and Department of Physics, University of Trento, Via Sommarive 14, I-38123 Trento, Italy
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10
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Gong Z, Yoshioka N, Shibata N, Hamazaki R. Universal Error Bound for Constrained Quantum Dynamics. PHYSICAL REVIEW LETTERS 2020; 124:210606. [PMID: 32530663 DOI: 10.1103/physrevlett.124.210606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 03/13/2020] [Accepted: 05/01/2020] [Indexed: 06/11/2023]
Abstract
It is well known in quantum mechanics that a large energy gap between a Hilbert subspace of specific interest and the remainder of the spectrum can suppress transitions from the quantum states inside the subspace to those outside due to additional couplings that mix these states, and thus approximately lead to a constrained dynamics within the subspace. While this statement has widely been used to approximate quantum dynamics in various contexts, a general and quantitative justification stays lacking. Here we establish an observable-based error bound for such a constrained-dynamics approximation in generic gapped quantum systems. This universal bound is a linear function of time that only involves the energy gap and coupling strength, provided that the latter is much smaller than the former. We demonstrate that either the intercept or the slope in the bound is asymptotically saturable by simple models. We generalize the result to quantum many-body systems with local interactions, for which the coupling strength diverges in the thermodynamic limit while the error is found to grow no faster than a power law t^{d+1} in d dimensions. Our work establishes a universal and rigorous result concerning nonequilibrium quantum dynamics.
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Affiliation(s)
- Zongping Gong
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Nobuyuki Yoshioka
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Reserach (CPR), Wako-shi, Saitama 351-0198, Japan
| | - Naoyuki Shibata
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Ryusuke Hamazaki
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- Nonequilibrium Quantum Statistical Mechanics RIKEN Hakubi Research Team, RIKEN Cluster for Pioneering Research (CPR), RIKEN iTHEMS, Wako, Saitama 351-0198, Japan
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11
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Klco N, Savage MJ, Stryker JR. SU(2) non-Abelian gauge field theory in one dimension on digital quantum computers. Int J Clin Exp Med 2020. [DOI: 10.1103/physrevd.101.074512] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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12
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Cardarelli L, Greschner S, Santos L. Deconfining Disordered Phase in Two-Dimensional Quantum Link Models. PHYSICAL REVIEW LETTERS 2020; 124:123601. [PMID: 32281853 DOI: 10.1103/physrevlett.124.123601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 03/03/2020] [Indexed: 06/11/2023]
Abstract
We explore the ground-state physics of two-dimensional spin-1/2 U(1) quantum link models, one of the simplest nontrivial lattice gauge theories with fermionic matter within experimental reach for quantum simulations. Whereas in the large mass limit we observe Neél-like vortex-antivortex and striped crystalline phases, for small masses there is a transition from the striped phases into a disordered phase whose properties resemble those at the Rokhsar-Kivelson point of the quantum dimer model. This phase is characterized on ladders by boundary Haldane-like properties, such as vanishing parity and finite string ordering. Moreover, from studies of the string tension between gauge charges, we find that, whereas the striped phases are confined, the novel disordered phase present clear indications of being deconfined. Our results open exciting perspectives of studying highly nontrivial physics in quantum simulators, such as spin-liquid behavior and confinement-deconfinement transitions, without the need of explicitly engineering plaquette terms.
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Affiliation(s)
- Lorenzo Cardarelli
- Institut für Theoretische Physik, Leibniz Universität Hannover, Appelstr. 2, DE-30167 Hannover, Germany
| | - Sebastian Greschner
- Department of Quantum Matter Physics, University of Geneva, CH-1211 Geneva, Switzerland
| | - Luis Santos
- Institut für Theoretische Physik, Leibniz Universität Hannover, Appelstr. 2, DE-30167 Hannover, Germany
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13
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Mil A, Zache TV, Hegde A, Xia A, Bhatt RP, Oberthaler MK, Hauke P, Berges J, Jendrzejewski F. A scalable realization of local U(1) gauge invariance in cold atomic mixtures. Science 2020; 367:1128-1130. [PMID: 32139542 DOI: 10.1126/science.aaz5312] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 02/04/2020] [Indexed: 11/02/2022]
Abstract
In the fundamental laws of physics, gauge fields mediate the interaction between charged particles. An example is the quantum theory of electrons interacting with the electromagnetic field, based on U(1) gauge symmetry. Solving such gauge theories is in general a hard problem for classical computational techniques. Although quantum computers suggest a way forward, large-scale digital quantum devices for complex simulations are difficult to build. We propose a scalable analog quantum simulator of a U(1) gauge theory in one spatial dimension. Using interspecies spin-changing collisions in an atomic mixture, we achieve gauge-invariant interactions between matter and gauge fields with spin- and species-independent trapping potentials. We experimentally realize the elementary building block as a key step toward a platform for quantum simulations of continuous gauge theories.
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Affiliation(s)
- Alexander Mil
- Kirchhoff-Institut für Physik, Heidelberg University, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany.
| | - Torsten V Zache
- Institut für Theoretische Physik, Heidelberg University, Philosophenweg 16, 69120 Heidelberg, Germany
| | - Apoorva Hegde
- Kirchhoff-Institut für Physik, Heidelberg University, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany
| | - Andy Xia
- Kirchhoff-Institut für Physik, Heidelberg University, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany
| | - Rohit P Bhatt
- Kirchhoff-Institut für Physik, Heidelberg University, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany
| | - Markus K Oberthaler
- Kirchhoff-Institut für Physik, Heidelberg University, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany
| | - Philipp Hauke
- Kirchhoff-Institut für Physik, Heidelberg University, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany.,Institut für Theoretische Physik, Heidelberg University, Philosophenweg 16, 69120 Heidelberg, Germany.,INO-CNR BEC Center and Department of Physics, University of Trento, Via Sommarive 14, I-38123 Trento, Italy
| | - Jürgen Berges
- Institut für Theoretische Physik, Heidelberg University, Philosophenweg 16, 69120 Heidelberg, Germany
| | - Fred Jendrzejewski
- Kirchhoff-Institut für Physik, Heidelberg University, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany
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14
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Carmen Bañuls M, Cichy K. Review on novel methods for lattice gauge theories. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2020; 83:024401. [PMID: 31846938 DOI: 10.1088/1361-6633/ab6311] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Formulating gauge theories on a lattice offers a genuinely non-perturbative way of studying quantum field theories, and has led to impressive achievements. In particular, it significantly deepened our understanding of quantum chromodynamics. Yet, some very relevant problems remain inherently challenging, such as real time evolution, or the presence of a chemical potential, cases in which Monte Carlo simulations are hindered by a sign problem. In the last few years, a number of possible alternatives have been put forward, based on quantum information ideas, which could potentially open the access to areas of research that have so far eluded more standard methods. They include tensor network calculations, quantum simulations with different physical platforms and quantum computations, and constitute nowadays a vibrant research area. Experts from different fields, including experimental and theoretical high energy physics, condensed matter, and quantum information, are turning their attention to these interdisciplinary possibilities, and driving the progress of the field. The aim of this article is to review the status and perspectives of these new avenues for the exploration of lattice gauge theories.
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Affiliation(s)
- Mari Carmen Bañuls
- Max-Planck Institut, für Quantenoptik, Garching 85748, Germany. Munich Center for Quantum Science and Technology (MCQST), Schellingstr. 4, Munich 80799, Germany
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15
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A new approach to study the Zeno effect for a macroscopic quantum system under frequent interactions with a harmonic environment. Sci Rep 2019; 9:15265. [PMID: 31649291 PMCID: PMC6813307 DOI: 10.1038/s41598-019-51729-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 10/07/2019] [Indexed: 11/16/2022] Open
Abstract
Quantum Zeno and anti-Zeno behaviors of a two-level macroscopic quantum system in interaction with a harmonic environment are studied using the perturbation theory. The system-environment interactions are applied in a successive and step-by-step way. A new expression for the probability of surviving the macrosystem in its initial state, after the Nth interaction step, is derived through a different method of calculation. It is shown that multiple transitions between Zeno and anti-Zeno behaviors can be found in our approach. We have shown that in addition to the environmental parameters like the Ohmicity, the macroscopic trait of the system also has a notable effect on the decay rate Γ(τ). Moreover, we have investigated how the decay rate Γ(τ) varies as the parameter of the macroscopicity of the system \documentclass[12pt]{minimal}
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16
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Cian ZP, Zhu G, Chu SK, Seif A, DeGottardi W, Jiang L, Hafezi M. Photon Pair Condensation by Engineered Dissipation. PHYSICAL REVIEW LETTERS 2019; 123:063602. [PMID: 31491141 DOI: 10.1103/physrevlett.123.063602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Indexed: 06/10/2023]
Abstract
Dissipation can usually induce detrimental decoherence in a quantum system. However, engineered dissipation can be used to prepare and stabilize coherent quantum many-body states. Here, we show that, by engineering dissipators containing photon pair operators, one can stabilize an exotic dark state, which is a condensate of photon pairs with a phase-nematic order. In this system, the usual superfluid order parameter, i.e., single-photon correlation, is absent, while the photon pair correlation exhibits long-range order. Although the dark state is not unique due to multiple parity sectors, we devise an additional type of dissipators to stabilize the dark state in a particular parity sector via a diffusive annihilation process which obeys Glauber dynamics in an Ising model. Furthermore, we propose an implementation of these photon pair dissipators in circuit-QED architecture.
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Affiliation(s)
- Ze-Pei Cian
- Department of Physics, University of Maryland, College Park, Maryland 20742, USA
- Joint Quantum Institute, NIST/University of Maryland, College Park, Maryland 20742, USA
| | - Guanyu Zhu
- Joint Quantum Institute, NIST/University of Maryland, College Park, Maryland 20742, USA
| | - Su-Kuan Chu
- Department of Physics, University of Maryland, College Park, Maryland 20742, USA
- Joint Quantum Institute, NIST/University of Maryland, College Park, Maryland 20742, USA
- Joint Center for Quantum Information and Computer Science, NIST/University of Maryland, College Park, Maryland 20742, USA
| | - Alireza Seif
- Department of Physics, University of Maryland, College Park, Maryland 20742, USA
- Joint Quantum Institute, NIST/University of Maryland, College Park, Maryland 20742, USA
| | - Wade DeGottardi
- Joint Quantum Institute, NIST/University of Maryland, College Park, Maryland 20742, USA
- Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742, USA
| | - Liang Jiang
- Departments of Applied Physics and Physics, Yale University, New Haven, Connecticut 06511, USA
- Yale Quantum Institute, Yale University, New Haven, Connecticut 06511, USA
| | - Mohammad Hafezi
- Department of Physics, University of Maryland, College Park, Maryland 20742, USA
- Joint Quantum Institute, NIST/University of Maryland, College Park, Maryland 20742, USA
- Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742, USA
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17
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Huang YP, Banerjee D, Heyl M. Dynamical Quantum Phase Transitions in U(1) Quantum Link Models. PHYSICAL REVIEW LETTERS 2019; 122:250401. [PMID: 31347880 DOI: 10.1103/physrevlett.122.250401] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 03/15/2019] [Indexed: 06/10/2023]
Abstract
Quantum link models (QLMs) are extensions of Wilson-type lattice gauge theories which realize exact gauge invariance with finite-dimensional Hilbert spaces. QLMs not only reproduce standard features of Wilson lattice gauge theories in equilibrium, but can also host new phenomena such as crystalline confined phases. The local constraints due to gauge invariance also provide kinetic restrictions that can influence substantially the real-time dynamics in these systems. We aim to characterize the nonequilibrium evolution in lattice gauge theories through the lens of dynamical quantum phase transitions, which provide general principles for real-time dynamics in quantum many-body systems. Specifically, we study quantum quenches for two representative cases, U(1) QLMs in (1+1)D and (2+1)D, for initial conditions exhibiting long-range order. Finally, we discuss the connection to the high-energy perspective and the experimental feasibility to observe the discussed phenomena in recent quantum simulator settings such as trapped ions, ultracold atoms, and Rydberg atoms.
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Affiliation(s)
- Yi-Ping Huang
- Max-Planck-Institut fur Physik komplexer Systeme, Nöthnitzer Strasse 38, 01187 Dresden, Germany
| | - Debasish Banerjee
- Max-Planck-Institut fur Physik komplexer Systeme, Nöthnitzer Strasse 38, 01187 Dresden, Germany
| | - Markus Heyl
- Max-Planck-Institut fur Physik komplexer Systeme, Nöthnitzer Strasse 38, 01187 Dresden, Germany
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18
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Tonielli F, Fazio R, Diehl S, Marino J. Orthogonality Catastrophe in Dissipative Quantum Many-Body Systems. PHYSICAL REVIEW LETTERS 2019; 122:040604. [PMID: 30768302 DOI: 10.1103/physrevlett.122.040604] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 01/09/2019] [Indexed: 06/09/2023]
Abstract
We present an analog of the phenomenon of orthogonality catastrophe in quantum many-body systems subject to a local dissipative impurity. We show that the fidelity F(t), giving a measure for distance of the time-evolved state from the initial one, displays a universal scaling form F(t)∝t^{θ}e^{-γt}, when the system supports long-range correlations, in a fashion reminiscent of traditional instances of orthogonality catastrophe in condensed matter. An exponential falloff at rate γ signals the onset of environmental decoherence, which is critically slowed down by the additional algebraic contribution to the fidelity. This picture is derived within a second-order cumulant expansion suited for Liouvillian dynamics, and substantiated for the one-dimensional transverse field quantum Ising model subject to a local dephasing jump operator, as well as for XY and XX quantum spin chains, and for the two-dimensional Bose gas deep in the superfluid phase with local particle heating. Our results hint that local sources of dissipation can be used to inspect real-time correlations and to induce a delay of decoherence in open quantum many-body systems.
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Affiliation(s)
- F Tonielli
- Institut für Theoretische Physik, Universität zu Köln, D-50937 Cologne, Germany
| | - R Fazio
- Abdus Salam ICTP, Strada Costiera 11, I-34151 Trieste, Italy and NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR, I-56126 Pisa, Italy
| | - S Diehl
- Institut für Theoretische Physik, Universität zu Köln, D-50937 Cologne, Germany
- Kavli Institute for Theoretical Physics, University of California, Santa Barbara, California 93106-4030, USA
| | - J Marino
- Kavli Institute for Theoretical Physics, University of California, Santa Barbara, California 93106-4030, USA
- Department of Physics, Harvard University, Cambridge Massachusetts 02138, USA and Department of Quantum Matter Physics, University of Geneva, 1211 Geneve, Switzerland
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19
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Majeed M, Chaudhry AZ. The quantum Zeno and anti-Zeno effects with non-selective projective measurements. Sci Rep 2018; 8:14887. [PMID: 30291274 PMCID: PMC6173781 DOI: 10.1038/s41598-018-33181-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 09/25/2018] [Indexed: 11/12/2022] Open
Abstract
In studies of the quantum Zeno and anti-Zeno effects, it is usual to consider rapid projective measurements with equal time intervals being performed on the system to check whether or not the system is in the initial state. These projective measurements are selective measurements in the sense that the measurement results are read out and only the case where all the measurement results correspond to the initial state is considered in the analysis of the effect of the measurements. In this paper, we extend such a treatment to consider the effect of repeated non-selective projective measurements – only the final measurement is required to correspond to the initial state, while we do not know the results of the intermediate measurements. We present a general formalism to derive the effective decay rate of the initial quantum state with such nonselective measurements. Importantly, we show that there is a difference between using non-selective projective measurements and the usual approach of considering only selective measurements only if we go beyond the weak system-environment coupling regime in models other than the usual population decay models. As such, we then apply our formalism to investigate the quantum Zeno and anti-Zeno effects for three exactly solvable system-environment models: a single two-level system undergoing dephasing, a single two-level system interacting with an environment of two-level systems and a large spin undergoing dephasing. Our results show that the quantum Zeno and anti-Zeno effects in the presence of non-selective projective measurements can differ very significantly as compared to the repeated selective measurement scenario.
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Affiliation(s)
- Mehwish Majeed
- School of Science & Engineering, Lahore University of Management Sciences (LUMS), Opposite Sector U, D.H.A, Lahore, 54792, Pakistan
| | - Adam Zaman Chaudhry
- School of Science & Engineering, Lahore University of Management Sciences (LUMS), Opposite Sector U, D.H.A, Lahore, 54792, Pakistan.
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20
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Ashida Y, Ueda M. Full-Counting Many-Particle Dynamics: Nonlocal and Chiral Propagation of Correlations. PHYSICAL REVIEW LETTERS 2018; 120:185301. [PMID: 29775368 DOI: 10.1103/physrevlett.120.185301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Indexed: 06/08/2023]
Abstract
The ability to measure single quanta allows the complete characterization of small quantum systems known as full-counting statistics. Quantum gas microscopy enables one to observe many-body systems at the single-atom precision. We extend the idea of full-counting statistics to nonequilibrium open many-particle dynamics and apply it to discuss the quench dynamics. By way of illustration, we consider an exactly solvable model to demonstrate the emergence of unique phenomena such as nonlocal and chiral propagation of correlations, leading to a concomitant oscillatory entanglement growth. We find that correlations can propagate beyond the conventional maximal speed, known as the Lieb-Robinson bound, at the cost of probabilistic nature of quantum measurement. These features become most prominent at the real-to-complex spectrum transition point of an underlying parity-time-symmetric effective non-Hermitian Hamiltonian. A possible experimental situation with quantum gas microscopy is discussed.
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Affiliation(s)
- Yuto Ashida
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Masahito Ueda
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
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21
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Tomita T, Nakajima S, Danshita I, Takasu Y, Takahashi Y. Observation of the Mott insulator to superfluid crossover of a driven-dissipative Bose-Hubbard system. SCIENCE ADVANCES 2017; 3:e1701513. [PMID: 29291246 PMCID: PMC5744470 DOI: 10.1126/sciadv.1701513] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 11/20/2017] [Indexed: 05/25/2023]
Abstract
Dissipation is ubiquitous in nature and plays a crucial role in quantum systems such as causing decoherence of quantum states. Recently, much attention has been paid to an intriguing possibility of dissipation as an efficient tool for the preparation and manipulation of quantum states. We report the realization of successful demonstration of a novel role of dissipation in a quantum phase transition using cold atoms. We realize an engineered dissipative Bose-Hubbard system by introducing a controllable strength of two-body inelastic collision via photoassociation for ultracold bosons in a three-dimensional optical lattice. In the dynamics subjected to a slow ramp-down of the optical lattice, we find that strong on-site dissipation favors the Mott insulating state: The melting of the Mott insulator is delayed, and the growth of the phase coherence is suppressed. The controllability of the dissipation is highlighted by quenching the dissipation, providing a novel method for investigating a quantum many-body state and its nonequilibrium dynamics.
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Affiliation(s)
- Takafumi Tomita
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Shuta Nakajima
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Ippei Danshita
- Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502, Japan
| | - Yosuke Takasu
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Yoshiro Takahashi
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
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22
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Analyzing the Quantum Zeno and anti-Zeno effects using optimal projective measurements. Sci Rep 2017; 7:11766. [PMID: 28924194 PMCID: PMC5603598 DOI: 10.1038/s41598-017-11787-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 08/30/2017] [Indexed: 11/09/2022] Open
Abstract
Measurements in quantum mechanics can not only effectively freeze the quantum system (the quantum Zeno effect) but also accelerate the time evolution of the system (the quantum anti-Zeno effect). In studies of these effects, a quantum state is prepared repeatedly by projecting the quantum state onto the initial state. In this paper, we repeatedly prepare the initial quantum state in a different manner. Instead of only performing projective measurements, we allow unitary operations to be performed, on a very short time-scale, after each measurement. We can then repeatedly prepare the initial state by performing some projective measurement and then, after each measurement, we perform a suitable unitary operation to end up with the same initial state as before. Our objective is to find the projective measurements that minimize the effective decay rate of the quantum state. We find such optimal measurements and the corresponding decay rates for a variety of system-environment models such as the pure dephasing model and the spin-boson model. We find that there can be considerable differences between this optimized effective decay rate and the usual decay rate obtained by repeatedly projecting onto the initial state. In particular, the Zeno and anti-Zeno regimes can be considerably modified.
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23
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Gong Z, Higashikawa S, Ueda M. Zeno Hall Effect. PHYSICAL REVIEW LETTERS 2017; 118:200401. [PMID: 28581785 DOI: 10.1103/physrevlett.118.200401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Indexed: 06/07/2023]
Abstract
We show that the quantum Zeno effect gives rise to the Hall effect by tailoring the Hilbert space of a two-dimensional lattice system into a single Bloch band with a nontrivial Berry curvature. Consequently, a wave packet undergoes transverse motion in response to a potential gradient-a phenomenon we call the Zeno Hall effect to highlight its quantum Zeno origin. The Zeno Hall effect leads to retroreflection at the edge of the system due to an interplay between the band flatness and the nontrivial Berry curvature. We propose an experimental implementation of this effect with ultracold atoms in an optical lattice.
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Affiliation(s)
- Zongping Gong
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Sho Higashikawa
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Masahito Ueda
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
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24
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Chaudhry AZ. The quantum Zeno and anti-Zeno effects with strong system-environment coupling. Sci Rep 2017; 7:1741. [PMID: 28496109 PMCID: PMC5431853 DOI: 10.1038/s41598-017-01844-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 04/04/2017] [Indexed: 11/25/2022] Open
Abstract
To date, studies of the quantum Zeno and anti-Zeno effects focus on quantum systems that are weakly interacting with their environment. In this paper, we investigate what happens to a quantum system under the action of repeated measurements if the quantum system is strongly interacting with its environment. We consider as the quantum system a single two-level system coupled strongly to a collection of harmonic oscillators. A so-called polaron transformation is then used to make the problem in the strong system-environment coupling regime tractable. We find that the strong coupling case exhibits quantitative and qualitative differences as compared with the weak coupling case. In particular, the effective decay rate does not depend linearly on the spectral density of the environment. This then means that, in the strong coupling regime that we investigate, increasing the system-environment coupling strength can actually decrease the effective decay rate. We also consider a collection of two-level atoms coupled strongly with a common environment. In this case, we find that there are further differences between the weak and strong coupling cases since the two-level atoms can now indirectly interact with one another due to the common environment.
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Affiliation(s)
- Adam Zaman Chaudhry
- School of Science & Engineering, Lahore University of Management Sciences (LUMS), Opposite Sector U, D.H.A, Lahore, 54792, Pakistan.
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25
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Zohar E, Farace A, Reznik B, Cirac JI. Digital Quantum Simulation of Z_{2} Lattice Gauge Theories with Dynamical Fermionic Matter. PHYSICAL REVIEW LETTERS 2017; 118:070501. [PMID: 28256852 DOI: 10.1103/physrevlett.118.070501] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Indexed: 05/29/2023]
Abstract
We propose a scheme for digital quantum simulation of lattice gauge theories with dynamical fermions. Using a layered optical lattice with ancilla atoms that can move and interact with the other atoms (simulating the physical degrees of freedom), we obtain a stroboscopic dynamics which yields the four-body plaquette interactions, arising in models with (2+1) and higher dimensions, without the use of perturbation theory. As an example we show how to simulate a Z_{2} model in (2+1) dimensions.
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Affiliation(s)
- Erez Zohar
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Straße 1, 85748 Garching, Germany
| | - Alessandro Farace
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Straße 1, 85748 Garching, Germany
| | - Benni Reznik
- School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel-Aviv 69978, Israel
| | - J Ignacio Cirac
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Straße 1, 85748 Garching, Germany
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26
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Zohar E, Farace A, Reznik B, Cirac JI. Digital Quantum Simulation of Z_{2} Lattice Gauge Theories with Dynamical Fermionic Matter. PHYSICAL REVIEW LETTERS 2017; 118:070501. [PMID: 28256852 DOI: 10.1103/physreva.95.023604] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Indexed: 05/29/2023]
Abstract
We propose a scheme for digital quantum simulation of lattice gauge theories with dynamical fermions. Using a layered optical lattice with ancilla atoms that can move and interact with the other atoms (simulating the physical degrees of freedom), we obtain a stroboscopic dynamics which yields the four-body plaquette interactions, arising in models with (2+1) and higher dimensions, without the use of perturbation theory. As an example we show how to simulate a Z_{2} model in (2+1) dimensions.
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Affiliation(s)
- Erez Zohar
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Straße 1, 85748 Garching, Germany
| | - Alessandro Farace
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Straße 1, 85748 Garching, Germany
| | - Benni Reznik
- School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel-Aviv 69978, Israel
| | - J Ignacio Cirac
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Straße 1, 85748 Garching, Germany
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27
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Brennen GK, Pupillo G, Rico E, Stace TM, Vodola D. Loops and Strings in a Superconducting Lattice Gauge Simulator. PHYSICAL REVIEW LETTERS 2016; 117:240504. [PMID: 28009201 DOI: 10.1103/physrevlett.117.240504] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Indexed: 06/06/2023]
Abstract
We propose an architecture for an analog quantum simulator of electromagnetism in 2+1 dimensions, based on an array of superconducting fluxonium devices. The encoding is in the integer (spin-1) representation of the quantum link model formulation of compact U(1) lattice gauge theory. We show how to engineer Gauss' law via an ancilla mediated gadget construction, and how to tune between the strongly coupled and intermediately coupled regimes. The witnesses to the existence of the predicted confining phase of the model are provided by nonlocal order parameters from Wilson loops and disorder parameters from 't Hooft strings. We show how to construct such operators in this model and how to measure them nondestructively via dispersive coupling of the fluxonium islands to a microwave cavity mode. Numerical evidence is found for the existence of the confined phase in the ground state of the simulation Hamiltonian on a ladder geometry.
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Affiliation(s)
- G K Brennen
- Centre for Engineered Quantum Systems, Department of Physics and Astronomy, Macquarie University, Sydney, NSW 2109, Australia
| | - G Pupillo
- icFRC, IPCMS (UMR 7504) and ISIS (UMR 7006), Universite de Strasbourg and CNRS,67000 Strasbourg, France
| | - E Rico
- Department of Physical Chemistry, University of the Basque Country UPV/EHU, Apartado 644, E-48080 Bilbao, Spain
- IKERBASQUE, Basque Foundation for Science, Maria Diaz de Haro 3, E-48013 Bilbao, Spain
| | - T M Stace
- Center for Engineered Quantum Systems, School of Mathematics and Physics, The University of Queensland, St Lucia, Queensland 4072, Australia
| | - D Vodola
- icFRC, IPCMS (UMR 7504) and ISIS (UMR 7006), Universite de Strasbourg and CNRS,67000 Strasbourg, France
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28
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Chaudhry AZ. A general framework for the Quantum Zeno and anti-Zeno effects. Sci Rep 2016; 6:29497. [PMID: 27405268 PMCID: PMC4942788 DOI: 10.1038/srep29497] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 06/20/2016] [Indexed: 01/12/2023] Open
Abstract
Repeated measurements can slow down (the quantum Zeno effect) or speed up (the quantum anti-Zeno effect) the temporal evolution of a quantum system. In this paper, a general treatment of the quantum Zeno and anti-Zeno effects is presented which is valid for an arbitrary system-environment model in the weak system-environment coupling regime. It is shown that the effective lifetime of a quantum state that is subjected to repeated projective measurements depends on the overlap of the spectral density of the environment and a generalized ‘filter function’. This filter function depends on the system-environment Hamiltonian, the state of the environment, and the measurement being performed. Our general framework is then used to study explicitly the Zeno to anti-Zeno crossover behaviour for the spin-boson model where a single two-level system is coupled to a bosonic environment. It is possible to not only reproduce results for the usual population decay case as well as for the pure dephasing model, but to also study the regime where both decay and dephasing take place. These results are then extended to many two-level systems coupled collectively to the bosonic environment to further illustrate the importance of the correct evaluation of the effective decay rate.
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Affiliation(s)
- Adam Zaman Chaudhry
- School of Science &Engineering, Lahore University of Management Sciences (LUMS), Opposite Sector U, D.H.A., Lahore 54792, Pakistan
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29
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Zohar E, Cirac JI, Reznik B. Quantum simulations of lattice gauge theories using ultracold atoms in optical lattices. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2016; 79:014401. [PMID: 26684222 DOI: 10.1088/0034-4885/79/1/014401] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Can high-energy physics be simulated by low-energy, non-relativistic, many-body systems such as ultracold atoms? Such ultracold atomic systems lack the type of symmetries and dynamical properties of high energy physics models: in particular, they manifest neither local gauge invariance nor Lorentz invariance, which are crucial properties of the quantum field theories which are the building blocks of the standard model of elementary particles. However, it turns out, surprisingly, that there are ways to configure an atomic system to manifest both local gauge invariance and Lorentz invariance. In particular, local gauge invariance can arise either as an effective low-energy symmetry, or as an exact symmetry, following from the conservation laws in atomic interactions. Hence, one could hope that such quantum simulators may lead to a new type of (table-top) experiments which will be used to study various QCD (quantum chromodynamics) phenomena, such as the confinement of dynamical quarks, phase transitions and other effects, which are inaccessible using the currently known computational methods. In this report, we review the Hamiltonian formulation of lattice gauge theories, and then describe our recent progress in constructing the quantum simulation of Abelian and non-Abelian lattice gauge theories in 1 + 1 and 2 + 1 dimensions using ultracold atoms in optical lattices.
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Affiliation(s)
- Erez Zohar
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Straß e 1, 85748 Garching, Germany
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30
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Mezzacapo A, Rico E, Sabín C, Egusquiza IL, Lamata L, Solano E. Non-Abelian SU(2) Lattice Gauge Theories in Superconducting Circuits. PHYSICAL REVIEW LETTERS 2015; 115:240502. [PMID: 26705616 DOI: 10.1103/physrevlett.115.240502] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Indexed: 06/05/2023]
Abstract
We propose a digital quantum simulator of non-Abelian pure-gauge models with a superconducting circuit setup. Within the framework of quantum link models, we build a minimal instance of a pure SU(2) gauge theory, using triangular plaquettes involving geometric frustration. This realization is the least demanding, in terms of quantum simulation resources, of a non-Abelian gauge dynamics. We present two superconducting architectures that can host the quantum simulation, estimating the requirements needed to run possible experiments. The proposal establishes a path to the experimental simulation of non-Abelian physics with solid-state quantum platforms.
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Affiliation(s)
- A Mezzacapo
- Department of Physical Chemistry, University of the Basque Country UPV/EHU, Apartado 644, 48080 Bilbao, Spain
- IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - E Rico
- Department of Physical Chemistry, University of the Basque Country UPV/EHU, Apartado 644, 48080 Bilbao, Spain
- IKERBASQUE, Basque Foundation for Science, Maria Diaz de Haro 3, 48013 Bilbao, Spain
| | - C Sabín
- School of Mathematical Sciences, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - I L Egusquiza
- Department of Theoretical Physics and History of Science, University of the Basque Country UPV/EHU, Apartado 644, 48080 Bilbao, Spain
| | - L Lamata
- Department of Physical Chemistry, University of the Basque Country UPV/EHU, Apartado 644, 48080 Bilbao, Spain
| | - E Solano
- Department of Physical Chemistry, University of the Basque Country UPV/EHU, Apartado 644, 48080 Bilbao, Spain
- IKERBASQUE, Basque Foundation for Science, Maria Diaz de Haro 3, 48013 Bilbao, Spain
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31
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Caballero-Benitez SF, Mekhov IB. Quantum Optical Lattices for Emergent Many-Body Phases of Ultracold Atoms. PHYSICAL REVIEW LETTERS 2015; 115:243604. [PMID: 26705634 DOI: 10.1103/physrevlett.115.243604] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Indexed: 06/05/2023]
Abstract
Confining ultracold gases in cavities creates a paradigm of quantum trapping potentials. We show that this allows us to bridge models with global collective and short-range interactions as novel quantum phases possess properties of both. Some phases appear solely due to quantum light-matter correlations. Because of a global, but spatially structured, interaction, the competition between quantum matter and light waves leads to multimode structures even in single-mode cavities, including delocalized dimers of matter-field coherences (bonds), beyond density orders as supersolids and density waves.
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Affiliation(s)
| | - Igor B Mekhov
- Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
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32
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Abstract
Quantum Zeno effect shows that frequent observations can slow down or even stop the unitary time evolution of an unstable quantum system. This effect can also be regarded as a physical consequence of the statistical indistinguishability of neighboring quantum states. The accessibility of quantum Zeno dynamics under unitary time evolution can be quantitatively estimated by quantum Zeno time in terms of Fisher information. In this work, we investigate the accessibility of quantum Zeno dynamics in quantum open systems by calculating noisy Fisher information when a trace preserving and completely positive map is assumed. We firstly study the consequences of non-Markovian noise on quantum Zeno effect and give the exact forms of the dissipative Fisher information and the quantum Zeno time. Then, for the operator-sum representation, an achievable upper bound of the quantum Zeno time is given with the help of the results in noisy quantum metrology. It is of significance that the noise reducing the accuracy in the entanglement-enhanced parameter estimation can conversely be favorable for the accessibility of quantum Zeno dynamics of entangled states.
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33
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Schäfer F, Herrera I, Cherukattil S, Lovecchio C, Cataliotti FS, Caruso F, Smerzi A. Experimental realization of quantum zeno dynamics. Nat Commun 2015; 5:3194. [PMID: 24476716 PMCID: PMC3916840 DOI: 10.1038/ncomms4194] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 01/02/2014] [Indexed: 11/09/2022] Open
Abstract
It is generally impossible to probe a quantum system without disturbing it. However, it is possible to exploit the back action of quantum measurements and strong couplings to tailor and protect the coherent evolution of a quantum system. This is a profound and counterintuitive phenomenon known as quantum Zeno dynamics. Here we demonstrate quantum Zeno dynamics with a rubidium Bose–Einstein condensate in a five-level Hilbert space. We harness measurements and strong couplings to dynamically disconnect different groups of quantum states and constrain the atoms to coherently evolve inside a two-level subregion. In parallel to the foundational importance due to the realization of a dynamical superselection rule and the theory of quantum measurements, this is an important step forward in protecting and controlling quantum dynamics and, broadly speaking, quantum information processing. While a quantum system is always disturbed by any observation, one can exploit the back action of measurements and strong couplings to tailor the system evolution via quantum Zeno dynamics. Schäfer et al. demonstrate quantum Zeno dynamics in a five-level Hilbert space using a 87Rb Bose–Einstein condensate.
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Affiliation(s)
- F Schäfer
- 1] LENS-Università di Firenze, Via Nello Carrara 1, 50019 Sesto Fiorentino, Italy [2] Dipartimento di Fisica ed Astronomia, Via Sansone 1, 50019 Sesto Fiorentino, Italy
| | - I Herrera
- LENS-Università di Firenze, Via Nello Carrara 1, 50019 Sesto Fiorentino, Italy
| | - S Cherukattil
- LENS-Università di Firenze, Via Nello Carrara 1, 50019 Sesto Fiorentino, Italy
| | - C Lovecchio
- LENS-Università di Firenze, Via Nello Carrara 1, 50019 Sesto Fiorentino, Italy
| | - F S Cataliotti
- 1] LENS-Università di Firenze, Via Nello Carrara 1, 50019 Sesto Fiorentino, Italy [2] Dipartimento di Fisica ed Astronomia, Via Sansone 1, 50019 Sesto Fiorentino, Italy [3] QSTAR, Largo Enrico Fermi 2, 50125 Firenze, Italy
| | - F Caruso
- 1] LENS-Università di Firenze, Via Nello Carrara 1, 50019 Sesto Fiorentino, Italy [2] Dipartimento di Fisica ed Astronomia, Via Sansone 1, 50019 Sesto Fiorentino, Italy [3] QSTAR, Largo Enrico Fermi 2, 50125 Firenze, Italy
| | - A Smerzi
- 1] LENS-Università di Firenze, Via Nello Carrara 1, 50019 Sesto Fiorentino, Italy [2] QSTAR, Largo Enrico Fermi 2, 50125 Firenze, Italy [3] Istituto Nazionale di Ottica, INO-CNR, Largo Enrico Fermi 2, 50125 Firenze, Italy
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34
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Elliott TJ, Kozlowski W, Caballero-Benitez SF, Mekhov IB. Multipartite entangled spatial modes of ultracold atoms generated and controlled by quantum measurement. PHYSICAL REVIEW LETTERS 2015; 114:113604. [PMID: 25839270 DOI: 10.1103/physrevlett.114.113604] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Indexed: 06/04/2023]
Abstract
We show that the effect of measurement backaction results in the generation of multiple many-body spatial modes of ultracold atoms trapped in an optical lattice, when scattered light is detected. The multipartite mode entanglement properties and their nontrivial spatial overlap can be varied by tuning the optical geometry in a single setup. This can be used to engineer quantum states and dynamics of matter fields. We provide examples of multimode generalizations of parametric down-conversion, Dicke, and other states; investigate the entanglement properties of such states; and show how they can be transformed into a class of generalized squeezed states. Furthermore, we propose how these modes can be used to detect and measure entanglement in quantum gases.
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Affiliation(s)
- T J Elliott
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - W Kozlowski
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - S F Caballero-Benitez
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - I B Mekhov
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
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35
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Zanardi P, Campos Venuti L. Coherent quantum dynamics in steady-state manifolds of strongly dissipative systems. PHYSICAL REVIEW LETTERS 2014; 113:240406. [PMID: 25541757 DOI: 10.1103/physrevlett.113.240406] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Indexed: 06/04/2023]
Abstract
Recently, it has been realized that dissipative processes can be harnessed and exploited to the end of coherent quantum control and information processing. In this spirit, we consider strongly dissipative quantum systems admitting a nontrivial manifold of steady states. We show how one can enact adiabatic coherent unitary manipulations, e.g., quantum logical gates, inside this steady-state manifold by adding a weak, time-rescaled, Hamiltonian term into the system's Liouvillian. The effective long-time dynamics is governed by a projected Hamiltonian which results from the interplay between the weak unitary control and the fast relaxation process. The leakage outside the steady-state manifold entailed by the Hamiltonian term is suppressed by an environment-induced symmetrization of the dynamics. We present applications to quantum-computation in decoherence-free subspaces and noiseless subsystems and numerical analysis of nonadiabatic errors.
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Affiliation(s)
- Paolo Zanardi
- Department of Physics and Astronomy, and Center for Quantum Information Science and Technology, University of Southern California, Los Angeles, California 90089-0484, USA
| | - Lorenzo Campos Venuti
- Department of Physics and Astronomy, and Center for Quantum Information Science and Technology, University of Southern California, Los Angeles, California 90089-0484, USA
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36
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Burgarth DK, Facchi P, Giovannetti V, Nakazato H, Pascazio S, Yuasa K. Exponential rise of dynamical complexity in quantum computing through projections. Nat Commun 2014; 5:5173. [PMID: 25300692 PMCID: PMC4214416 DOI: 10.1038/ncomms6173] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2014] [Accepted: 09/08/2014] [Indexed: 11/22/2022] Open
Abstract
The ability of quantum systems to host exponentially complex dynamics has the potential to revolutionize science and technology. Therefore, much effort has been devoted to developing of protocols for computation, communication and metrology, which exploit this scaling, despite formidable technical difficulties. Here we show that the mere frequent observation of a small part of a quantum system can turn its dynamics from a very simple one into an exponentially complex one, capable of universal quantum computation. After discussing examples, we go on to show that this effect is generally to be expected: almost any quantum dynamics becomes universal once ‘observed’ as outlined above. Conversely, we show that any complex quantum dynamics can be ‘purified’ into a simpler one in larger dimensions. We conclude by demonstrating that even local noise can lead to an exponentially complex dynamics. It is an old adage in quantum physics that the observation of a system changes its properties, as exemplified by the quantum Zeno effect. Now, Burgarth et al. show that such repeated measurement of a quantum system actually enriches its dynamics, letting it explore a much larger algebra than it did before.
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Affiliation(s)
- Daniel Klaus Burgarth
- Institute of Mathematics, Physics and Computer Science, Aberystwyth University, Aberystwyth SY23 3BZ, UK
| | - Paolo Facchi
- 1] Dipartimento di Fisica and MECENAS, Università di Bari, I-70126 Bari, Italy [2] INFN, Sezione di Bari, I-70126 Bari, Italy
| | - Vittorio Giovannetti
- NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR, I-56126 Pisa, Italy
| | | | - Saverio Pascazio
- 1] Dipartimento di Fisica and MECENAS, Università di Bari, I-70126 Bari, Italy [2] INFN, Sezione di Bari, I-70126 Bari, Italy
| | - Kazuya Yuasa
- Department of Physics, Waseda University, Tokyo 169-8555, Japan
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