1
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Alamo M, Petiziol F, Eckardt A. Minimal quantum heat pump based on high-frequency driving and non-Markovianity. Phys Rev E 2024; 109:064121. [PMID: 39020951 DOI: 10.1103/physreve.109.064121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 05/08/2024] [Indexed: 07/20/2024]
Abstract
We propose a minimal setup for a quantum heat pump consisting of two tunnel-coupled quantum dots, each hosting a single level and each being coupled to a different fermionic reservoir. The working principle relies on both non-Markovian system-bath coupling and driving-induced resonant coupling. We describe the system using a reaction-coordinate mapping in combination with Floquet-Born-Markov theory and characterize its performance.
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2
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Liu Y, Wang Z, Yang C, Jie J, Wang Y. Dissipation-Induced Extended-Localized Transition. PHYSICAL REVIEW LETTERS 2024; 132:216301. [PMID: 38856294 DOI: 10.1103/physrevlett.132.216301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 02/05/2024] [Accepted: 04/23/2024] [Indexed: 06/11/2024]
Abstract
A mobility edge (ME), representing the critical energy that distinguishes between extended and localized states, is a key concept in understanding the transition between extended (metallic) and localized (insulating) states in disordered and quasiperiodic systems. Here we explore the impact of dissipation on a quasiperiodic system featuring MEs by calculating steady-state density matrix and analyzing quench dynamics with sudden introduction of dissipation. We demonstrate that dissipation can lead the system into specific states predominantly characterized by either extended or localized states, irrespective of the initial state. Our results establish the use of dissipation as a new avenue for inducing transitions between extended and localized states and for manipulating dynamic behaviors of particles.
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Affiliation(s)
- Yaru Liu
- Shenzhen Key Laboratory of Ultraintense Laser and Advanced Material Technology, Center for Intense Laser Application Technology, and College of Engineering Physics, Shenzhen Technology University, Shenzhen 518118, China
- Department of Physics, Renmin University of China, Beijing 100872, China
| | - Zeqing Wang
- Department of Physics, Renmin University of China, Beijing 100872, China
| | - Chao Yang
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Jianwen Jie
- Shenzhen Key Laboratory of Ultraintense Laser and Advanced Material Technology, Center for Intense Laser Application Technology, and College of Engineering Physics, Shenzhen Technology University, Shenzhen 518118, China
| | - Yucheng Wang
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
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3
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Li S, Gong M, Li YH, Jiang H, Xie XC. High spin axion insulator. Nat Commun 2024; 15:4250. [PMID: 38762497 PMCID: PMC11102527 DOI: 10.1038/s41467-024-48542-4] [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: 11/12/2023] [Accepted: 05/03/2024] [Indexed: 05/20/2024] Open
Abstract
Axion insulators possess a quantized axion field θ = π protected by combined lattice and time-reversal symmetry, holding great potential for device applications in layertronics and quantum computing. Here, we propose a high-spin axion insulator (HSAI) defined in large spin-s representation, which maintains the same inherent symmetry but possesses a notable axion field θ = (s + 1/2)2π. Such distinct axion field is confirmed independently by the direct calculation of the axion term using hybrid Wannier functions, layer-resolved Chern numbers, as well as the topological magneto-electric effect. We show that the guaranteed gapless quasi-particle excitation is absent at the boundary of the HSAI despite its integer surface Chern number, hinting an unusual quantum anomaly violating the conventional bulk-boundary correspondence. Furthermore, we ascertain that the axion field θ can be precisely tuned through an external magnetic field, enabling the manipulation of bonded transport properties. The HSAI proposed here can be experimentally verified in ultra-cold atoms by the quantized non-reciprocal conductance or topological magnetoelectric response. Our work enriches the understanding of axion insulators in condensed matter physics, paving the way for future device applications.
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Affiliation(s)
- Shuai Li
- School of Physical Science and Technology, Soochow University, Suzhou, 215006, China
- Institute for Advanced Study, Soochow University, Suzhou, 215006, China
| | - Ming Gong
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871, China
| | - Yu-Hang Li
- School of Physics, Nankai University, Tianjin, 300071, China.
| | - Hua Jiang
- Institute for Advanced Study, Soochow University, Suzhou, 215006, China.
- Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai, 200433, China.
- Interdisciplinary Center for Theoretical Physics and Information Sciences (ICTPIS), Fudan University, Shanghai, 200433, China.
| | - X C Xie
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871, China
- Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai, 200433, China
- Interdisciplinary Center for Theoretical Physics and Information Sciences (ICTPIS), Fudan University, Shanghai, 200433, China
- Hefei National Laboratory, Hefei, 230088, China
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4
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Maksimov DN, Aksenov SV, Kolovsky AR. Non-Markovian master equation for quantum transport of fermionic carriers. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 36:045301. [PMID: 37832566 DOI: 10.1088/1361-648x/ad0351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 10/13/2023] [Indexed: 10/15/2023]
Abstract
We propose a simple, yet feasible, model for quantum transport of fermionic carriers across tight-binding chain connecting two reservoirs maintained at arbitrary temperatures and chemical potentials. The model allows for elementary derivation of the master equation for the reduced single particle density matrix (SPDM) in a closed form in both Markov and Born approximations. In the Markov approximation the master equation is solved analytically, whereas in the Born approximation the problem is reduced to an algebraic equation for the SPDM in the Redfield form. The non-Markovian equation is shown to lead to resonant transport similar to Landauer's conductance. It is shown that in the deep non-Markovian regime the transport current can be matched with that obtained by the non-equilibrium Green's function method.
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Affiliation(s)
- D N Maksimov
- IRC SQC, Siberian Federal University, 660041 Krasnoyarsk, Russia
- Kirensky Institute of Physics, Federal Research Center KSC SB RAS, 660036 Krasnoyarsk, Russia
| | - S V Aksenov
- Kirensky Institute of Physics, Federal Research Center KSC SB RAS, 660036 Krasnoyarsk, Russia
| | - A R Kolovsky
- Kirensky Institute of Physics, Federal Research Center KSC SB RAS, 660036 Krasnoyarsk, Russia
- School of Engineering Physics and Radio Electronics, Siberian Federal University, 660041 Krasnoyarsk, Russia
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5
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Gałka M, Christodoulou P, Gazo M, Karailiev A, Dogra N, Schmitt J, Hadzibabic Z. Emergence of Isotropy and Dynamic Scaling in 2D Wave Turbulence in a Homogeneous Bose Gas. PHYSICAL REVIEW LETTERS 2022; 129:190402. [PMID: 36399756 DOI: 10.1103/physrevlett.129.190402] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Revised: 08/24/2022] [Accepted: 09/14/2022] [Indexed: 06/16/2023]
Abstract
We realize a turbulent cascade of wave excitations in a homogeneous 2D Bose gas and probe on all relevant time and length scales how it builds up from small to large momenta, until the system reaches a steady state with matching energy injection and dissipation. This all-scales view directly reveals the two theoretically expected cornerstones of turbulence formation-the emergence of statistical momentum-space isotropy under anisotropic forcing and the spatiotemporal scaling of the momentum distribution at times before any energy is dissipated.
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Affiliation(s)
- Maciej Gałka
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Panagiotis Christodoulou
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Martin Gazo
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Andrey Karailiev
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Nishant Dogra
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Julian Schmitt
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
- Institut für Angewandte Physik, Universität Bonn, Wegelerstraße 8, 53115 Bonn, Germany
| | - Zoran Hadzibabic
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
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6
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Trisnadi J, Zhang M, Weiss L, Chin C. Design and construction of a quantum matter synthesizer. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:083203. [PMID: 36050064 DOI: 10.1063/5.0100088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 07/23/2022] [Indexed: 06/15/2023]
Abstract
The quantum matter synthesizer (QMS) is a new quantum simulation platform in which individual particles in a lattice can be resolved and re-arranged into arbitrary patterns. The ability to spatially manipulate ultracold atoms and control their tunneling and interactions at the single-particle level allows full control of a many-body quantum system. We present the design and characterization of the QMS, which integrates into a single ultra-stable apparatus a two-dimensional optical lattice, a moving optical tweezer array formed by a digital micromirror device, and site-resolved atomic imaging. We demonstrate excellent mechanical stability between the lattice and tweezer array with relative fluctuations below 10 nm, diffraction-limited imaging at a resolution of 655 nm, and high-speed real-time control of the tweezer array at a 2.52 kHz refresh rate, which will be adopted to realize fast rearrangement of atoms. The QMS also features new technologies and schemes, such as nanotextured anti-reflective windows and all-optical long-distance transport of atoms.
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Affiliation(s)
- Jonathan Trisnadi
- James Franck Institute, Enrico Fermi Institute, and Department of Physics, The University of Chicago, Chicago, Illinois 60637, USA
| | - Mingjiamei Zhang
- James Franck Institute, Enrico Fermi Institute, and Department of Physics, The University of Chicago, Chicago, Illinois 60637, USA
| | - Lauren Weiss
- James Franck Institute, Enrico Fermi Institute, and Department of Physics, The University of Chicago, Chicago, Illinois 60637, USA
| | - Cheng Chin
- James Franck Institute, Enrico Fermi Institute, and Department of Physics, The University of Chicago, Chicago, Illinois 60637, USA
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7
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Sarkar S, Dubi Y. Emergence and Dynamical Stability of a Charge Time-Crystal in a Current-Carrying Quantum Dot Simulator. NANO LETTERS 2022; 22:4445-4451. [PMID: 35580301 DOI: 10.1021/acs.nanolett.2c00976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Periodically driven open quantum systems that never thermalize exhibit a discrete time-crystal behavior, a nonequilibrium quantum phenomenon that has shown promise in quantum information processing applications. Measurements of time-crystallinity are currently limited to (magneto-) optical experiments in atom-cavity systems and spin-systems making it an indirect measurement. We theoretically show that time-crystallinity can be measured directly in the charge-current from a spin-less Hubbard ladder, which can be simulated on a quantum-dot array. We demonstrate that one can dynamically tune the system out and then back on a time-crystal phase, proving its robustness against external forcings. These findings motivate further theoretical and experimental efforts to simulate the time-crystal phenomena in current-carrying nanoscale systems.
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Affiliation(s)
- Subhajit Sarkar
- Department of Chemistry, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
- School of Electrical and Computer Engineering, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Yonatan Dubi
- Department of Chemistry, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
- Ilse Katz Center for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
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8
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Riera-Campeny A, Sanpera A, Strasberg P. Open quantum systems coupled to finite baths: A hierarchy of master equations. Phys Rev E 2022; 105:054119. [PMID: 35706239 DOI: 10.1103/physreve.105.054119] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 04/26/2022] [Indexed: 06/15/2023]
Abstract
An open quantum system in contact with an infinite bath approaches equilibrium, while the state of the bath remains unchanged. If the bath is finite, the open system still relaxes to equilibrium but it induces a dynamical evolution of the bath state. In this paper, we study the dynamics of open quantum systems in contact with finite baths. We obtain a hierarchy of master equations that improve their accuracy by including more dynamical information of the bath. For instance, as the least accurate but simplest description in the hierarchy, we obtain the conventional Born-Markov-secular master equation. Remarkably, our framework works even if the measurements of the bath energy are imperfect, which not only is more realistic but also unifies the theoretical description. Also, we discuss this formalism in detail for a particular noninteracting environment where the Boltzmann temperature and the Kubo-Martin-Schwinger relation naturally arise. Finally, we apply our hierarchy of master equations to study the central spin model.
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Affiliation(s)
- Andreu Riera-Campeny
- Física Teòrica: Informació i Fenòmens Quàntics, Departament de Física, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Anna Sanpera
- Física Teòrica: Informació i Fenòmens Quàntics, Departament de Física, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
- ICREA, Psg. Lluís Companys 23, 08001 Barcelona, Spain
| | - Philipp Strasberg
- Física Teòrica: Informació i Fenòmens Quàntics, Departament de Física, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
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9
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Lee CH. Exceptional Bound States and Negative Entanglement Entropy. PHYSICAL REVIEW LETTERS 2022; 128:010402. [PMID: 35061451 DOI: 10.1103/physrevlett.128.010402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 11/29/2021] [Indexed: 06/14/2023]
Abstract
This Letter introduces a new class of robust states known as exceptional bound (EB) states, which are distinct from the well-known topological and non-Hermitian skin boundary states. EB states occur in the presence of exceptional points, which are non-Hermitian critical points where eigenstates coalesce and fail to span the Hilbert space. This eigenspace defectiveness not only limits the accessibility of state information but also interplays with long-range order to give rise to singular propagators only possible in non-Hermitian settings. Their resultant EB eigenstates are characterized by robust anomalously large or negative occupation probabilities, unlike ordinary Fermi sea states whose probabilities lie between 0 and 1. EB states remain robust after a variety of quantum quenches and give rise to enigmatic negative entanglement entropy contributions. Through suitable perturbations, the coefficient of the logarithmic entanglement entropy scaling can be continuously tuned. EB states represent a new avenue for robustness arising from geometric defectiveness, independent of topological protection or nonreciprocal pumping.
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Affiliation(s)
- Ching Hua Lee
- Department of Physics, National University of Singapore, Singapore 117542, Singapore
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10
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Strasberg P, Díaz MG, Riera-Campeny A. Clausius inequality for finite baths reveals universal efficiency improvements. Phys Rev E 2021; 104:L022103. [PMID: 34525673 DOI: 10.1103/physreve.104.l022103] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 08/04/2021] [Indexed: 06/13/2023]
Abstract
We study entropy production in nanoscale devices, which are coupled to finite heat baths. This situation is of growing experimental relevance, but most theoretical approaches rely on a formulation of the second law valid only for infinite baths. We fix this problem by pointing out that Clausius' paper from 1865 already contains an adequate formulation of the second law for finite heat baths, which can be also rigorously derived from a microscopic quantum description. This Clausius inequality shows that nonequilibrium processes are less irreversible than previously thought. We use it to correctly extend Landauer's principle to finite baths and we demonstrate that any heat engine in contact with finite baths has a higher efficiency than previously thought. Importantly, our results are easy to study, requiring only the knowledge of the average bath energy.
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Affiliation(s)
- Philipp Strasberg
- Física Teòrica: Informació i Fenòmens Quàntics, Departament de Física, Universitat Autònoma de Barcelona, 08193 Bellaterra (Barcelona), Spain
| | - María García Díaz
- Física Teòrica: Informació i Fenòmens Quàntics, Departament de Física, Universitat Autònoma de Barcelona, 08193 Bellaterra (Barcelona), Spain
| | - Andreu Riera-Campeny
- Física Teòrica: Informació i Fenòmens Quàntics, Departament de Física, Universitat Autònoma de Barcelona, 08193 Bellaterra (Barcelona), Spain
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11
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White DH, Haase TA, Brown DJ, Hoogerland MD, Najafabadi MS, Helm JL, Gies C, Schumayer D, Hutchinson DAW. Observation of two-dimensional Anderson localisation of ultracold atoms. Nat Commun 2020; 11:4942. [PMID: 33009375 PMCID: PMC7532155 DOI: 10.1038/s41467-020-18652-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Accepted: 09/01/2020] [Indexed: 11/29/2022] Open
Abstract
Anderson localisation -the inhibition of wave propagation in disordered media- is a surprising interference phenomenon which is particularly intriguing in two-dimensional (2D) systems. While an ideal, non-interacting 2D system of infinite size is always localised, the localisation length-scale may be too large to be unambiguously observed in an experiment. In this sense, 2D is a marginal dimension between one-dimension, where all states are strongly localised, and three-dimensions, where a well-defined phase transition between localisation and delocalisation exists as the energy is increased. Here, we report the results of an experiment measuring the 2D transport of ultracold atoms between two reservoirs, which are connected by a channel containing pointlike disorder. The design overcomes many of the technical challenges that have hampered observation of localisation in previous works. We experimentally observe exponential localisation in a 2D ultracold atom system.
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Affiliation(s)
- Donald H White
- Dodd-Walls Centre for Photonic and Quantum Technologies, Department of Physics, University of Auckland, Auckland, New Zealand
- Waseda Research Institute for Science and Engineering, Waseda University, Shinjuku, Tokyo, Japan
| | - Thomas A Haase
- Dodd-Walls Centre for Photonic and Quantum Technologies, Department of Physics, University of Auckland, Auckland, New Zealand
| | - Dylan J Brown
- Dodd-Walls Centre for Photonic and Quantum Technologies, Department of Physics, University of Auckland, Auckland, New Zealand
- Light-Matter Interactions for Quantum Technologies Unit, Okinawa Institute of Science and Technology, Tancha, Onna, Okinawa, Japan
| | - Maarten D Hoogerland
- Dodd-Walls Centre for Photonic and Quantum Technologies, Department of Physics, University of Auckland, Auckland, New Zealand.
| | - Mojdeh S Najafabadi
- Dodd-Walls Centre for Photonic and Quantum Technologies, Department of Physics, University of Auckland, Auckland, New Zealand
- Dodd-Walls Centre for Photonic and Quantum Technologies, Department of Physics, University of Otago, Dunedin, New Zealand
| | - John L Helm
- Dodd-Walls Centre for Photonic and Quantum Technologies, Department of Physics, University of Auckland, Auckland, New Zealand
- Dodd-Walls Centre for Photonic and Quantum Technologies, Department of Physics, University of Otago, Dunedin, New Zealand
| | - Christopher Gies
- Institut für Theoretische Physik, Universität Bremen, Bremen, Germany
| | - Daniel Schumayer
- Dodd-Walls Centre for Photonic and Quantum Technologies, Department of Physics, University of Auckland, Auckland, New Zealand
- Dodd-Walls Centre for Photonic and Quantum Technologies, Department of Physics, University of Otago, Dunedin, New Zealand
| | - David A W Hutchinson
- Dodd-Walls Centre for Photonic and Quantum Technologies, Department of Physics, University of Auckland, Auckland, New Zealand.
- Dodd-Walls Centre for Photonic and Quantum Technologies, Department of Physics, University of Otago, Dunedin, New Zealand.
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12
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Kolovsky AR. Quantum entanglement and the Born-Markov approximation for an open quantum system. Phys Rev E 2020; 101:062116. [PMID: 32688548 DOI: 10.1103/physreve.101.062116] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 05/22/2020] [Indexed: 11/07/2022]
Abstract
We revisit the Born-Markov approximation for an open quantum system by considering a microscopic model of the bath, namely, the Bose-Hubbard chain in the parameter region where it is chaotic in the sense of quantum chaos. It is shown that strong ergodic properties of the bath justify all approximations required for deriving the Markovian master equation from the first principles.
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Affiliation(s)
- Andrey R Kolovsky
- Kirensky Institute of Physics, 660036 Krasnoyarsk, Russia and Siberian Federal University, 660041 Krasnoyarsk, Russia
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13
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Bychek AA, Muraev PS, Maksimov DN, Kolovsky AR. Open Bose-Hubbard chain: Pseudoclassical approach. Phys Rev E 2020; 101:012208. [PMID: 32069667 DOI: 10.1103/physreve.101.012208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Indexed: 06/10/2023]
Abstract
We analyze the stationary current of bosonic carriers in the Bose-Hubbard chain of length L where the first and the last sites of the chain are attached to reservoirs of Bose particles acting as a particle source and sink, respectively. The analysis is carried out by using the pseudoclassical approach which reduces the original quantum problem to the classical problem for L coupled nonlinear oscillators. It is shown that an increase of oscillator nonlinearity (which is determined by the strength of interparticle interactions) results in a transition from the ballistic transport regime, where the stationary current is independent of the chain length, to the diffusive regime, where the current is inversely proportional to L.
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Affiliation(s)
- A A Bychek
- Kirensky Institute of Physics, 660036 Krasnoyarsk, Russia
| | - P S Muraev
- School of Engineering Physics and Radio Electronics, Siberian Federal University, 660041 Krasnoyarsk, Russia
| | - D N Maksimov
- Kirensky Institute of Physics, 660036 Krasnoyarsk, Russia
- School of Engineering Physics and Radio Electronics, Siberian Federal University, 660041 Krasnoyarsk, Russia
| | - A R Kolovsky
- Kirensky Institute of Physics, 660036 Krasnoyarsk, Russia
- School of Engineering Physics and Radio Electronics, Siberian Federal University, 660041 Krasnoyarsk, Russia
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14
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Gauthier G, Szigeti SS, Reeves MT, Baker M, Bell TA, Rubinsztein-Dunlop H, Davis MJ, Neely TW. Quantitative Acoustic Models for Superfluid Circuits. PHYSICAL REVIEW LETTERS 2019; 123:260402. [PMID: 31951434 DOI: 10.1103/physrevlett.123.260402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Indexed: 06/10/2023]
Abstract
We experimentally realize a highly tunable superfluid oscillator circuit in a quantum gas of ultracold atoms and develop and verify a simple lumped-element description of this circuit. At low oscillator currents, we demonstrate that the circuit is accurately described as a Helmholtz resonator, a fundamental element of acoustic circuits. At larger currents, the breakdown of the Helmholtz regime is heralded by a turbulent shedding of vortices and density waves. Although a simple phase-slip model offers qualitative insights into the circuit's resistive behavior, our results indicate deviations from the phase-slip model. A full understanding of the dissipation in superfluid circuits will thus require the development of empirical models of the turbulent dynamics in this system, as have been developed for classical acoustic systems.
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Affiliation(s)
- Guillaume Gauthier
- ARC Centre of Excellence for Engineered Quantum Systems, School of Mathematics and Physics, University of Queensland, Brisbane, QLD 4072, Australia
| | - Stuart S Szigeti
- ARC Centre of Excellence for Engineered Quantum Systems, School of Mathematics and Physics, University of Queensland, Brisbane, QLD 4072, Australia
- Department of Quantum Science, Research School of Physics, The Australian National University, Canberra 2601, Australia
| | - Matthew T Reeves
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies, School of Mathematics and Physics, University of Queensland, Brisbane, QLD 4072, Australia
| | - Mark Baker
- ARC Centre of Excellence for Engineered Quantum Systems, School of Mathematics and Physics, University of Queensland, Brisbane, QLD 4072, Australia
| | - Thomas A Bell
- ARC Centre of Excellence for Engineered Quantum Systems, School of Mathematics and Physics, University of Queensland, Brisbane, QLD 4072, Australia
| | - Halina Rubinsztein-Dunlop
- ARC Centre of Excellence for Engineered Quantum Systems, School of Mathematics and Physics, University of Queensland, Brisbane, QLD 4072, Australia
| | - Matthew J Davis
- ARC Centre of Excellence for Engineered Quantum Systems, School of Mathematics and Physics, University of Queensland, Brisbane, QLD 4072, Australia
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies, School of Mathematics and Physics, University of Queensland, Brisbane, QLD 4072, Australia
| | - Tyler W Neely
- ARC Centre of Excellence for Engineered Quantum Systems, School of Mathematics and Physics, University of Queensland, Brisbane, QLD 4072, Australia
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15
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Biella A, Collura M, Rossini D, De Luca A, Mazza L. Ballistic transport and boundary resistances in inhomogeneous quantum spin chains. Nat Commun 2019; 10:4820. [PMID: 31645569 PMCID: PMC6811644 DOI: 10.1038/s41467-019-12784-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 09/27/2019] [Indexed: 11/21/2022] Open
Abstract
Transport phenomena are central to physics, and transport in the many-body and fully-quantum regime is attracting an increasing amount of attention. It has been recently revealed that some quantum spin chains support ballistic transport of excitations at all energies. However, when joining two semi-infinite ballistic parts, such as the XX and XXZ spin-1/2 models, our understanding suddenly becomes less established. Employing a matrix-product-state ansatz of the wavefunction, we study the relaxation dynamics in this latter case. Here we show that it takes place inside a light cone, within which two qualitatively different regions coexist: an inner one with a strong tendency towards thermalization, and an outer one supporting ballistic transport. We comment on the possibility that even at infinite time the system supports stationary currents and displays a non-zero Kapitza boundary resistance. Our study paves the way to the analysis of the interplay between transport, integrability, and local defects.
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Affiliation(s)
- Alberto Biella
- Université de Paris, Laboratoire Matériaux et Phénomènes Quantiques, CNRS, F-75013, Paris, France.
| | - Mario Collura
- Theoretische Physik, Universität des Saarlandes, D-66123, Saarbrücken, Germany
- Dipartimento di Fisica e Astronomia "G. Galilei", Università di Padova, I-35131, Padova, Italy
- SISSA - International School for Advanced Studies, I-34136, Trieste, Italy
| | - Davide Rossini
- Dipartimento di Fisica, Università di Pisa and INFN, Largo Pontecorvo 3, I-56127, Pisa, Italy
| | - Andrea De Luca
- The Rudolf Peierls Centre for Theoretical Physics, Oxford University, Oxford, OX1 3NP, UK
- Laboratoire de Physique Théorique et Modélisation (CNRS UMR 8089), Université de Cergy-Pontoise, F-95302, Cergy-Pontoise, France
| | - Leonardo Mazza
- LPTMS, UMR 8626, CNRS, Université Paris-Sud, Université Paris-Saclay, 91405, Orsay, France
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16
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Quantum State of the Fermionic Carriers in a Transport Channel Connecting Particle Reservoirs. CONDENSED MATTER 2019. [DOI: 10.3390/condmat4040085] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We analyze the quantum state of fermionic carriers in a transport channel attached to a particle reservoir. The analysis is done from first principles by considering microscopic models of the reservoir and transport channel. In the case of infinite effective temperature of the reservoir we demonstrate a full agreement between the results of straightforward numerical simulations of the system dynamics and the solution of the master equation on the single-particle density matrix of the carriers in the channel. This allows us to predict the quantum state of carriers in the case where the transport channel connects two reservoirs with different chemical potentials.
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17
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Pandey S, Mas H, Drougakis G, Thekkeppatt P, Bolpasi V, Vasilakis G, Poulios K, von Klitzing W. Hypersonic Bose-Einstein condensates in accelerator rings. Nature 2019; 570:205-209. [PMID: 31168098 DOI: 10.1038/s41586-019-1273-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 04/05/2019] [Indexed: 11/09/2022]
Abstract
Some of the most sensitive and precise measurements-for example, of inertia1, gravity2 and rotation3-are based on matter-wave interferometry with free-falling atomic clouds. To achieve very high sensitivities, the interrogation time has to be very long, and consequently the experimental apparatus needs to be very tall (in some cases reaching ten or even one hundred metres) or the experiments must be performed in microgravity in space4-7. Cancelling gravitational acceleration (for example, in atomtronic circuits8,9 and matter-wave guides10) is expected to result in compact devices with extended interrogation times and therefore increased sensitivity. Here we demonstrate smooth and controllable matter-wave guides by transporting Bose-Einstein condensates (BECs) over macroscopic distances. We use a neutral-atom accelerator ring to bring BECs to very high speeds (16 times their sound velocity) and transport them in a magnetic matter-wave guide for 15 centimetres while fully preserving their internal coherence. The resulting high angular momentum of more than 40,000ħ per atom (where ħ is the reduced Planck constant) gives access to the higher Landau levels of quantum Hall states, and the hypersonic velocities achieved, combined with our ability to control potentials with picokelvin precision, will facilitate the study of superfluidity and give rise to tunnelling and a large range of transport regimes of ultracold atoms11-13. Coherent matter-wave guides are expected to enable interaction times of several seconds in highly compact devices and lead to portable guided-atom interferometers for applications such as inertial navigation and gravity mapping.
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Affiliation(s)
- Saurabh Pandey
- Institute of Electronic Structure and Laser, Foundation for Research and Technology - Hellas, Heraklion, Greece.,Department of Materials Science and Technology, University of Crete, Heraklion, Greece
| | - Hector Mas
- Institute of Electronic Structure and Laser, Foundation for Research and Technology - Hellas, Heraklion, Greece.,Department of Physics, University of Crete, Heraklion, Greece
| | - Giannis Drougakis
- Institute of Electronic Structure and Laser, Foundation for Research and Technology - Hellas, Heraklion, Greece.,Department of Materials Science and Technology, University of Crete, Heraklion, Greece
| | - Premjith Thekkeppatt
- Institute of Electronic Structure and Laser, Foundation for Research and Technology - Hellas, Heraklion, Greece
| | - Vasiliki Bolpasi
- Institute of Electronic Structure and Laser, Foundation for Research and Technology - Hellas, Heraklion, Greece
| | - Georgios Vasilakis
- Institute of Electronic Structure and Laser, Foundation for Research and Technology - Hellas, Heraklion, Greece
| | - Konstantinos Poulios
- Institute of Electronic Structure and Laser, Foundation for Research and Technology - Hellas, Heraklion, Greece.,School of Physics and Astronomy, University of Nottingham, Nottingham, UK
| | - Wolf von Klitzing
- Institute of Electronic Structure and Laser, Foundation for Research and Technology - Hellas, Heraklion, Greece.
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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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Zwolak M. Communication: Gibbs phenomenon and the emergence of the steady-state in quantum transport. J Chem Phys 2018; 149:241102. [PMID: 30599719 PMCID: PMC6602063 DOI: 10.1063/1.5061759] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Simulations are increasingly employing explicit reservoirs-internal, finite regions-to drive electronic or particle transport. This naturally occurs in simulations of transport via ultracold atomic gases. Whether the simulation is numerical or physical, these approaches rely on the rapid development of the steady state. We demonstrate that steady state formation is a manifestation of the Gibbs phenomenon well-known in signal processing and in truncated discrete Fourier expansions. Each particle separately develops into an individual steady state due to the spreading of its wave packet in energy. The rise to the steady state for an individual particle depends on the particle energy-and thus can be slow-and ringing oscillations appear due to filtering of the response through the electronic bandwidth. However, the rise to the total steady state-the one from all particles-is rapid, with time scale π/W, where W is the bandwidth. Ringing oscillations are now also filtered through the bias window, and they decay with a higher power. The Gibbs constant-the overshoot of the first ring-can appear in the simulation error. These results shed light on the formation of the steady state and support the practical use of explicit reservoirs to simulate transport at the nanoscale or using ultracold atomic lattices.
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Affiliation(s)
- Michael Zwolak
- Biophysics Group, Microsystems and Nanotechnology Division, Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
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20
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Brown PT, Mitra D, Guardado-Sanchez E, Nourafkan R, Reymbaut A, Hébert CD, Bergeron S, Tremblay AMS, Kokalj J, Huse DA, Schauß P, Bakr WS. Bad metallic transport in a cold atom Fermi-Hubbard system. Science 2018; 363:379-382. [PMID: 30523078 DOI: 10.1126/science.aat4134] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 10/30/2018] [Indexed: 11/03/2022]
Abstract
Strong interactions in many-body quantum systems complicate the interpretation of charge transport in such materials. To shed light on this problem, we study transport in a clean quantum system: ultracold lithium-6 in a two-dimensional optical lattice, a testing ground for strong interaction physics in the Fermi-Hubbard model. We determine the diffusion constant by measuring the relaxation of an imposed density modulation and modeling its decay hydrodynamically. The diffusion constant is converted to a resistivity by using the Nernst-Einstein relation. That resistivity exhibits a linear temperature dependence and shows no evidence of saturation, two characteristic signatures of a bad metal. The techniques we developed in this study may be applied to measurements of other transport quantities, including the optical conductivity and thermopower.
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Affiliation(s)
- Peter T Brown
- Department of Physics, Princeton University, Princeton, NJ 08544, USA
| | - Debayan Mitra
- Department of Physics, Princeton University, Princeton, NJ 08544, USA
| | | | - Reza Nourafkan
- Département de Physique, Institut Quantique, and Regroupement Québécois sur les Matériaux de Pointe, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada
| | - Alexis Reymbaut
- Département de Physique, Institut Quantique, and Regroupement Québécois sur les Matériaux de Pointe, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada
| | - Charles-David Hébert
- Département de Physique, Institut Quantique, and Regroupement Québécois sur les Matériaux de Pointe, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada
| | - Simon Bergeron
- Département de Physique, Institut Quantique, and Regroupement Québécois sur les Matériaux de Pointe, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada
| | - A-M S Tremblay
- Département de Physique, Institut Quantique, and Regroupement Québécois sur les Matériaux de Pointe, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada.,Canadian Institute for Advanced Research, Toronto, Ontario M5G 1Z8, Canada
| | - Jure Kokalj
- Faculty of Civil and Geodetic Engineering, University of Ljubljana, SI-1000 Ljubljana, Slovenia.,Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia
| | - David A Huse
- Department of Physics, Princeton University, Princeton, NJ 08544, USA
| | - Peter Schauß
- Department of Physics, Princeton University, Princeton, NJ 08544, USA
| | - Waseem S Bakr
- Department of Physics, Princeton University, Princeton, NJ 08544, USA.
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21
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Scherg S, Kohlert T, Herbrych J, Stolpp J, Bordia P, Schneider U, Heidrich-Meisner F, Bloch I, Aidelsburger M. Nonequilibrium Mass Transport in the 1D Fermi-Hubbard Model. PHYSICAL REVIEW LETTERS 2018; 121:130402. [PMID: 30312049 DOI: 10.1103/physrevlett.121.130402] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 08/21/2018] [Indexed: 06/08/2023]
Abstract
We experimentally and numerically investigate the sudden expansion of fermions in a homogeneous one-dimensional optical lattice. For initial states with an appreciable amount of doublons, we observe a dynamical phase separation between rapidly expanding singlons and slow doublons remaining in the trap center, realizing the key aspect of fermionic quantum distillation in the strongly interacting limit. For initial states without doublons, we find a reduced interaction dependence of the asymptotic expansion speed compared to bosons, which is explained by the interaction energy produced in the quench.
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Affiliation(s)
- S Scherg
- Fakultät für Physik, Ludwig-Maximilians-Universität München, Munich, Germany
- Max-Planck-Institut für Quantenoptik, 85748 Garching, Germany
| | - T Kohlert
- Fakultät für Physik, Ludwig-Maximilians-Universität München, Munich, Germany
- Max-Planck-Institut für Quantenoptik, 85748 Garching, Germany
| | - J Herbrych
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
- Materials Science and Technology Division Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - J Stolpp
- Fakultät für Physik, Ludwig-Maximilians-Universität München, Munich, Germany
- Institute for Theoretical Physics, Georg-August-Universität Göttingen, 37077 Göttingen, Germany
- Arnold Sommerfeld Center for Theoretical Physics, Ludwig-Maximilians-Universität München, 80333 Munich, Germany
| | - P Bordia
- Fakultät für Physik, Ludwig-Maximilians-Universität München, Munich, Germany
- Max-Planck-Institut für Quantenoptik, 85748 Garching, Germany
| | - U Schneider
- Fakultät für Physik, Ludwig-Maximilians-Universität München, Munich, Germany
- Max-Planck-Institut für Quantenoptik, 85748 Garching, Germany
- Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - F Heidrich-Meisner
- Institute for Theoretical Physics, Georg-August-Universität Göttingen, 37077 Göttingen, Germany
| | - I Bloch
- Fakultät für Physik, Ludwig-Maximilians-Universität München, Munich, Germany
- Max-Planck-Institut für Quantenoptik, 85748 Garching, Germany
| | - M Aidelsburger
- Fakultät für Physik, Ludwig-Maximilians-Universität München, Munich, Germany
- Max-Planck-Institut für Quantenoptik, 85748 Garching, Germany
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22
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Gänger B, Phieler J, Nagler B, Widera A. A versatile apparatus for fermionic lithium quantum gases based on an interference-filter laser system. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:093105. [PMID: 30278689 DOI: 10.1063/1.5045827] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 08/25/2018] [Indexed: 06/08/2023]
Abstract
We report on the design and construction of a versatile setup for experiments with ultracold lithium (Li) gases. We discuss our methods to prepare an atomic beam and laser cool it in a Zeeman slower and a subsequent magneto-optical trap, which rely on established methods. We focus on our laser system based on a stable interference-filter-stabilized, linear-extended-cavity diode laser, so far unreported for lithium wavelengths. Moreover, we describe our optical setup to combine various laser frequencies for cooling, manipulation, and detection of Li atoms. We characterize the performance of our system preparing degenerate samples of Li atoms via forced evaporation in a hybrid crossed-beam optical-dipole trap plus confining magnetic trap. Our apparatus allows one to produce quantum gases of N ≈ 105…106 fermionic lithium-6 atoms at nanokelvin temperatures in cycle times below 10 s. Our optical system is particularly suited to study the dynamics of fermionic superfluids in engineered optical potentials.
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Affiliation(s)
- Benjamin Gänger
- Department of Physics and Research Center OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Jan Phieler
- Department of Physics and Research Center OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Benjamin Nagler
- Department of Physics and Research Center OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Artur Widera
- Department of Physics and Research Center OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany
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23
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Li L, Lee CH, Gong J. Realistic Floquet Semimetal with Exotic Topological Linkages between Arbitrarily Many Nodal Loops. PHYSICAL REVIEW LETTERS 2018; 121:036401. [PMID: 30085783 DOI: 10.1103/physrevlett.121.036401] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Indexed: 06/08/2023]
Abstract
Valence and conduction bands in nodal loop semimetals (NLSMs) touch along closed loops in momentum space. If such loops can proliferate and link intricately, NLSMs become exotic topological phases, which require nonlocal hopping and are therefore unrealistic in conventional quantum materials or cold atom systems alike. In this Letter, we show how this hurdle can be surmounted through an experimentally feasible periodic driving scheme. In particular, by tuning the period of a two-step periodic driving or certain experimentally accessible parameters, we can generate arbitrarily many nodal loops that are linked with various levels of complexity. Furthermore, we propose to use both a Berry-phase related winding number and the Alexander polynomial topological invariant to characterize the fascinating linkages among the nodal loops. This Letter thus presents a class of exotic Floquet topological phases that has hitherto not been proposed in any realistic setup. Possible experimental confirmation of such exotic topological phases is also discussed.
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Affiliation(s)
- Linhu Li
- Department of Physics, National University of Singapore, Singapore 117551, Republic of Singapore
| | - Ching Hua Lee
- Department of Physics, National University of Singapore, Singapore 117551, Republic of Singapore
- Institute of High Performance Computing, Singapore 138632, Republic of Singapore
| | - Jiangbin Gong
- Department of Physics, National University of Singapore, Singapore 117551, Republic of Singapore
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24
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Pereira E. Heat, work, and energy currents in the boundary-driven XXZ spin chain. Phys Rev E 2018; 97:022115. [PMID: 29548096 DOI: 10.1103/physreve.97.022115] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Indexed: 06/08/2023]
Abstract
We address the detailed study of the energy current and its components, heat and work, in the boundary-driven one-dimensional XXZ quantum model. We carry out the investigation by considering two different approaches present in the literature. First, we take the repeated interaction scheme and derive the expressions for the currents of heat and work, exchanged between system and baths. Then we perform the derivation of the energy current by means of a Lindblad master equation together with a continuity equation, another approach which is recurrently used. A comparison between the obtained expressions allows us to show the consistency of both approaches, and, in the latter expression derived from the Lindblad equation, it allows us to split the energy, which comes from the baths to the system, into heat and work. The recognition of work in the process, which is recurrently ignored in studies of transport, enables us to understand thermodynamical aspects and to solve some imbroglios in the physics behind the energy current in the XXZ spin chain.
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Affiliation(s)
- Emmanuel Pereira
- Departamento de Física-Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, CP 702, 30.161-970 Belo Horizonte MG, Brazil
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25
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Gruss D, Chien CC, Barreiro JT, Di Ventra M, Zwolak M. An energy-resolved atomic scanning probe. NEW JOURNAL OF PHYSICS 2018; 20:10.1088/1367-2630/aaedcf. [PMID: 31093010 PMCID: PMC6512978 DOI: 10.1088/1367-2630/aaedcf] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We propose a method to probe the local density of states (LDOS) of atomic systems that provides both spatial and energy resolution. The method combines atomic and tunneling techniques to supply a simple, yet quantitative and operational, definition of the LDOS for both interacting and non-interacting systems: It is the rate at which particles can be siphoned from the system of interest by a narrow energy band of non-interacting states contacted locally to the many-body system of interest. Ultracold atoms in optical lattices are a natural platform for implementing this broad concept to visualize the energy and spatial dependence of the atom density in interacting, inhomogeneous lattices. This includes models of strongly correlated condensed matter systems, as well as ones with non-trivial topologies.
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Affiliation(s)
- Daniel Gruss
- Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD 20899
- Maryland NanoCenter, University of Maryland, College Park, MD 20742
- Department of Physics, Oregon State University, Corvallis, OR 97331
| | - Chih-Chun Chien
- School of Natural Sciences, University of California, Merced, CA 95343
| | - Julio T Barreiro
- Department of Physics, University of California, San Diego, CA, 92093
| | | | - Michael Zwolak
- Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD 20899
- Biophysics Group, Microsystems & Nanotechnology Division, Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899
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26
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D'Errico C, Abbate SS, Modugno G. Quantum phase slips: from condensed matter to ultracold quantum gases. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2017; 375:20160425. [PMID: 29084890 PMCID: PMC5665781 DOI: 10.1098/rsta.2016.0425] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 07/25/2017] [Indexed: 06/07/2023]
Abstract
Quantum phase slips (QPS) are the primary excitations in one-dimensional superfluids and superconductors at low temperatures. They have been well characterized in most condensed-matter systems, and signatures of their existence have been recently observed in superfluids based on quantum gases too. In this review, we briefly summarize the main results obtained on the investigation of phase slips from superconductors to quantum gases. In particular, we focus our attention on recent experimental results of the dissipation in one-dimensional Bose superfluids flowing along a shallow periodic potential, which show signatures of QPS.This article is part of the themed issue 'Breakdown of ergodicity in quantum systems: from solids to synthetic matter'.
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Affiliation(s)
- C D'Errico
- Istituto Nazionale di Ottica, CNR, 50019 Sesto Fiorentino, Italy
- LENS and Dipartimento di Fisica e Astronomia, Università di Firenze, 50019 Sesto Fiorentino, Italy
| | - S Scaffidi Abbate
- LENS and Dipartimento di Fisica e Astronomia, Università di Firenze, 50019 Sesto Fiorentino, Italy
| | - G Modugno
- Istituto Nazionale di Ottica, CNR, 50019 Sesto Fiorentino, Italy
- LENS and Dipartimento di Fisica e Astronomia, Università di Firenze, 50019 Sesto Fiorentino, Italy
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27
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Mueller EJ. Review of pseudogaps in strongly interacting Fermi gases. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2017; 80:104401. [PMID: 28686169 DOI: 10.1088/1361-6633/aa7e53] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A central challenge in modern condensed matter physics is developing the tools for understanding nontrivial yet unordered states of matter. One important idea to emerge in this context is that of a 'pseudogap': the fact that under appropriate circumstances the normal state displays a suppression of the single particle spectral density near the Fermi level, reminiscent of the gaps seen in ordered states of matter. While these concepts arose in a solid state context, they are now being explored in cold gases. This article reviews the current experimental and theoretical understanding of the normal state of strongly interacting Fermi gases, with particular focus on the phenomonology which is traditionally associated with the pseudogap.
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Affiliation(s)
- Erich J Mueller
- Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca NY 14853, United States of America
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28
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Krinner S, Esslinger T, Brantut JP. Two-terminal transport measurements with cold atoms. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:343003. [PMID: 28749788 DOI: 10.1088/1361-648x/aa74a1] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In recent years, the ability of cold atom experiments to explore condensed-matter-related questions has dramatically progressed. Transport experiments, in particular, have expanded to the point in which conductance and other transport coefficients can now be measured in a way that is directly analogous to solid-state physics, extending cold-atom-based quantum simulations into the domain of quantum electronic devices. In this topical review, we describe the transport experiments performed with cold gases in the two-terminal configuration, with an emphasis on the specific features of cold atomic gases compared to solid-state physics. We present the experimental techniques and the main experimental findings, focusing on-but not restricted to-the recent experiments performed by our group. We finally discuss the perspectives opened up by this approach, the main technical and conceptual challenges for future developments, and potential applications in quantum simulation for transport phenomena and mesoscopic physics problems.
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Affiliation(s)
- Sebastian Krinner
- Institute for Quantum Electronics, ETH Zurich, 8093 Zurich, Switzerland
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29
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Yan M, Hui HY, Rigol M, Scarola VW. Equilibration Dynamics of Strongly Interacting Bosons in 2D Lattices with Disorder. PHYSICAL REVIEW LETTERS 2017; 119:073002. [PMID: 28949694 DOI: 10.1103/physrevlett.119.073002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Indexed: 06/07/2023]
Abstract
Motivated by recent optical lattice experiments [J.-y. Choi et al., Science 352, 1547 (2016)SCIEAS0036-807510.1126/science.aaf8834], we study the dynamics of strongly interacting bosons in the presence of disorder in two dimensions. We show that Gutzwiller mean-field theory (GMFT) captures the main experimental observations, which are a result of the competition between disorder and interactions. Our findings highlight the difficulty in distinguishing glassy dynamics, which can be captured by GMFT, and many-body localization, which cannot be captured by GMFT, and indicate the need for further experimental studies of this system.
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Affiliation(s)
- Mi Yan
- Department of Physics, Virginia Tech, Blacksburg, Virginia 24061, USA
| | - Hoi-Yin Hui
- Department of Physics, Virginia Tech, Blacksburg, Virginia 24061, USA
| | - Marcos Rigol
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - V W Scarola
- Department of Physics, Virginia Tech, Blacksburg, Virginia 24061, USA
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30
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Tran DT, Dauphin A, Grushin AG, Zoller P, Goldman N. Probing topology by "heating": Quantized circular dichroism in ultracold atoms. SCIENCE ADVANCES 2017; 3:e1701207. [PMID: 28835930 PMCID: PMC5562418 DOI: 10.1126/sciadv.1701207] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2017] [Accepted: 07/16/2017] [Indexed: 05/30/2023]
Abstract
We reveal an intriguing manifestation of topology, which appears in the depletion rate of topological states of matter in response to an external drive. This phenomenon is presented by analyzing the response of a generic two-dimensional (2D) Chern insulator subjected to a circular time-periodic perturbation. Because of the system's chiral nature, the depletion rate is shown to depend on the orientation of the circular shake; taking the difference between the rates obtained from two opposite orientations of the drive, and integrating over a proper drive-frequency range, provides a direct measure of the topological Chern number (ν) of the populated band: This "differential integrated rate" is directly related to the strength of the driving field through the quantized coefficient η0 = ν/ℏ2, where h = 2π ℏ is Planck's constant. Contrary to the integer quantum Hall effect, this quantized response is found to be nonlinear with respect to the strength of the driving field, and it explicitly involves interband transitions. We investigate the possibility of probing this phenomenon in ultracold gases and highlight the crucial role played by edge states in this effect. We extend our results to 3D lattices, establishing a link between depletion rates and the nonlinear photogalvanic effect predicted for Weyl semimetals. The quantized circular dichroism revealed in this work designates depletion rate measurements as a universal probe for topological order in quantum matter.
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Affiliation(s)
- Duc Thanh Tran
- Center for Nonlinear Phenomena and Complex Systems, Université Libre de Bruxelles, CP 231, Campus Plaine, B-1050 Brussels, Belgium
| | - Alexandre Dauphin
- ICFO–Institut de Ciencies Fotoniques, Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain
| | - Adolfo G. Grushin
- Department of Physics, University of California, Berkeley, CA 94720, USA
- Institut Néel, CNRS and Université Grenoble Alpes, F-38042 Grenoble, France
| | - Peter Zoller
- International Solvay Institutes, Université Libre de Bruxelles, Campus Plaine, B-1050 Brussels, Belgium
- Institute for Theoretical Physics, University of Innsbruck, A-6020 Innsbruck, Austria
- Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, A-6020 Innsbruck, Austria
| | - Nathan Goldman
- Center for Nonlinear Phenomena and Complex Systems, Université Libre de Bruxelles, CP 231, Campus Plaine, B-1050 Brussels, Belgium
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31
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Häusler S, Nakajima S, Lebrat M, Husmann D, Krinner S, Esslinger T, Brantut JP. Scanning Gate Microscope for Cold Atomic Gases. PHYSICAL REVIEW LETTERS 2017; 119:030403. [PMID: 28777599 DOI: 10.1103/physrevlett.119.030403] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Indexed: 06/07/2023]
Abstract
We present a scanning probe microscopy technique for spatially resolving transport in cold atomic gases, in close analogy with scanning gate microscopy in semiconductor physics. The conductance of a quantum point contact connected to two atomic reservoirs is measured in the presence of a tightly focused laser beam acting as a local perturbation that can be precisely positioned in space. By scanning its position and recording the subsequent variations of conductance, we retrieve a high-resolution map of transport through a quantum point contact. We demonstrate a spatial resolution comparable to the extent of the transverse wave function of the atoms inside the channel and a position sensitivity below 10 nm. Our measurements agree well with an analytical model and ab initio numerical simulations, allowing us to identify a regime in transport where tunneling dominates over thermal effects. Our technique opens new perspectives for the high-resolution observation and manipulation of cold atomic gases.
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Affiliation(s)
- Samuel Häusler
- Department of Physics, ETH Zurich, 8093 Zurich, Switzerland
| | - Shuta Nakajima
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Martin Lebrat
- Department of Physics, ETH Zurich, 8093 Zurich, Switzerland
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32
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Uchino S, Ueda M. Anomalous Transport in the Superfluid Fluctuation Regime. PHYSICAL REVIEW LETTERS 2017; 118:105303. [PMID: 28339264 DOI: 10.1103/physrevlett.118.105303] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Indexed: 06/06/2023]
Abstract
Motivated by a recent experiment in ultracold atoms [S. Krinner et al., Proc. Natl. Acad. Sci. U.S.A. 113, 8144 (2016)PNASA60027-842410.1073/pnas.1601812113], we analyze transport of attractively interacting fermions through a one-dimensional wire near the superfluid transition. We show that in a ballistic regime where the conductance is quantized in the absence of interaction, the conductance is renormalized by superfluid fluctuations in reservoirs. In particular, the particle conductance is strongly enhanced, and the conductance plateau is blurred by emergent bosonic pair transport. For spin transport, in addition to the contact resistance, the wire itself is resistive, leading to a suppression of the measured spin conductance. Our results are qualitatively consistent with the experimental observations.
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Affiliation(s)
- Shun Uchino
- RIKEN Center for Emergent Matter Science, Wako, Saitama 351-0198, Japan
| | - Masahito Ueda
- RIKEN Center for Emergent Matter Science, Wako, Saitama 351-0198, Japan
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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33
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Eich FG, Di Ventra M, Vignale G. Functional theories of thermoelectric phenomena. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:063001. [PMID: 27991434 DOI: 10.1088/1361-648x/29/6/063001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We review the progress that has been recently made in the application of time-dependent density functional theory to thermoelectric phenomena. As the field is very young, we emphasize open problems and fundamental issues. We begin by introducing the formal structure of thermal density functional theory, a density functional theory with two basic variables-the density and the energy density-and two conjugate fields-the ordinary scalar potential and Luttinger's thermomechanical potential. The static version of this theory is contrasted with the familiar finite-temperature density functional theory, in which only the density is a variable. We then proceed to constructing the full time-dependent non equilibrium theory, including the practically important Kohn-Sham equations that go with it. The theory is shown to recover standard results of the Landauer theory for thermal transport in the steady state, while showing greater flexibility by allowing a description of fast thermal response, temperature oscillations and related phenomena. Several results are presented here for the first time, i.e. the proof of invertibility of the thermal response function in the linear regime, the full expression of the thermal currents in the presence of Luttinger's thermomechanical potential, an explicit prescription for the evaluation of the Kohn-Sham potentials in the adiabatic local density approximation, a detailed discussion of the leading dissipative corrections to the adiabatic local density approximation and the thermal corrections to the resistivity that follow from it.
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Affiliation(s)
- F G Eich
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, D-22761 Hamburg, Germany. Department of Physics, University of Missouri-Columbia, Columbia, MO 65211, USA
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Challenges and constraints of dynamically emerged source and sink in atomtronic circuits: From closed-system to open-system approaches. Sci Rep 2016; 6:37256. [PMID: 27849034 PMCID: PMC5110959 DOI: 10.1038/srep37256] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 10/26/2016] [Indexed: 11/08/2022] Open
Abstract
While batteries offer electronic source and sink for electronic devices, atomic analogues of source and sink and their theoretical descriptions have been a challenge in cold-atom systems. Here we consider dynamically emerged local potentials as controllable source and sink for bosonic atoms. Although a sink potential can collect bosons in equilibrium and indicate its usefulness in the adiabatic limit, sudden switching of the potential exhibits low effectiveness in pushing bosons into it. This is due to conservation of energy and particle in isolated systems such as cold atoms. By varying the potential depth and interaction strength, the systems can further exhibit averse response, where a deeper emerged potential attracts less bosonic atoms into it. To explore possibilities for improving the effectiveness, we investigate what types of system-environment coupling can help bring bosons into a dynamically emerged sink, and a Lindblad operator corresponding to local cooling is found to serve the purpose.
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35
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Finite-temperature fluid-insulator transition of strongly interacting 1D disordered bosons. Proc Natl Acad Sci U S A 2016; 113:E4455-9. [PMID: 27436894 DOI: 10.1073/pnas.1606908113] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We consider the many-body localization-delocalization transition for strongly interacting one-dimensional disordered bosons and construct the full picture of finite temperature behavior of this system. This picture shows two insulator-fluid transitions at any finite temperature when varying the interaction strength. At weak interactions, an increase in the interaction strength leads to insulator [Formula: see text] fluid transition, and, for large interactions, there is a reentrance to the insulator regime. It is feasible to experimentally verify these predictions by tuning the interaction strength with the use of Feshbach or confinement-induced resonances, for example, in (7)Li or (39)K.
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Abstract
We study particle and spin transport in a single-mode quantum point contact, using a charge neutral, quantum degenerate Fermi gas with tunable, attractive interactions. This yields the spin and particle conductance of the point contact as a function of chemical potential or confinement. The measurements cover a regime from weak attraction, where quantized conductance is observed, to the resonantly interacting superfluid. Spin conductance exhibits a broad maximum when varying the chemical potential at moderate interactions, which signals the emergence of Cooper pairing. In contrast, the particle conductance is unexpectedly enhanced even before the gas is expected to turn into a superfluid, continuously rising from the plateau at [Formula: see text] for weak interactions to plateau-like features at nonuniversal values as high as [Formula: see text] for intermediate interactions. For strong interactions, the particle conductance plateaus disappear and the spin conductance gets suppressed, confirming the spin-insulating character of a superfluid. Our observations document the breakdown of universal conductance quantization as many-body correlations appear. The observed anomalous quantization challenges a Fermi liquid description of the normal phase, shedding new light on the nature of the strongly attractive Fermi gas.
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37
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Shpielberg O, Akkermans E. Le Chatelier Principle for Out-of-Equilibrium and Boundary-Driven Systems: Application to Dynamical Phase Transitions. PHYSICAL REVIEW LETTERS 2016; 116:240603. [PMID: 27367375 DOI: 10.1103/physrevlett.116.240603] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Indexed: 06/06/2023]
Abstract
A stability analysis is presented for boundary-driven and out-of-equilibrium systems in the framework of the hydrodynamic macroscopic fluctuation theory. A Hamiltonian description is proposed which allows us to thermodynamically interpret the additivity principle. A necessary and sufficient condition for the validity of the additivity principle is obtained as an extension of the Le Chatelier principle. These stability conditions result from a diagonal quadratic form obtained using the cumulant generating function. This approach allows us to provide a proof for the stability of the weakly asymmetric exclusion process and to reduce the search for stability to the solution of two coupled linear ordinary differential equations instead of nonlinear partial differential equations. Additional potential applications of these results are discussed in the realm of classical and quantum systems.
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Affiliation(s)
- O Shpielberg
- Department of Physics, Technion Israel Institute of Technology, Haifa 32000, Israel
| | - E Akkermans
- Department of Physics, Technion Israel Institute of Technology, Haifa 32000, Israel
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38
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Eckel S, Lee JG, Jendrzejewski F, Lobb CJ, Campbell GK, Hill WT. Contact resistance and phase slips in mesoscopic superfluid atom transport. PHYSICAL REVIEW. A 2016; 93:10.1103/PhysRevA.93.063619. [PMID: 36733381 PMCID: PMC9890817 DOI: 10.1103/physreva.93.063619] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We have experimentally measured transport of superfluid, bosonic atoms in a mesoscopic system: a small channel connecting two large reservoirs. Starting far from equilibrium (superfluid in a single reservoir), we observe first resistive flow transitioning at a critical current into superflow, characterized by oscillations. We reproduce this full evolution with a simple electronic circuit model. We compare our fitted conductance to two different microscopic phenomenological models. We also show that the oscillations are consistent with LC oscillations as estimated by the kinetic inductance and effective capacitance in our system. Our experiment provides an attractive platform to begin to probe the mesoscopic transport properties of a dilute, superfluid, Bose gas.
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39
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Ott H. Single atom detection in ultracold quantum gases: a review of current progress. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2016; 79:054401. [PMID: 27093632 DOI: 10.1088/0034-4885/79/5/054401] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The recent advances in single atom detection and manipulation in experiments with ultracold quantum gases are reviewed. The discussion starts with the basic principles of trapping, cooling and detecting single ions and atoms. The realization of single atom detection in ultracold quantum gases is presented in detail and the employed methods, which are based on light scattering, electron scattering, field ionization and direct neutral particle detection are discussed. The microscopic coherent manipulation of single atoms in a quantum gas is also covered. Various examples are given in order to highlight the power of these approaches to study many-body quantum systems.
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Affiliation(s)
- Herwig Ott
- Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern, Germany
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40
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Price HM, Zilberberg O, Ozawa T, Carusotto I, Goldman N. Four-Dimensional Quantum Hall Effect with Ultracold Atoms. PHYSICAL REVIEW LETTERS 2015; 115:195303. [PMID: 26588394 DOI: 10.1103/physrevlett.115.195303] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Indexed: 06/05/2023]
Abstract
We propose a realistic scheme to detect the 4D quantum Hall effect using ultracold atoms. Based on contemporary technology, motion along a synthetic fourth dimension can be accomplished through controlled transitions between internal states of atoms arranged in a 3D optical lattice. From a semiclassical analysis, we identify the linear and nonlinear quantized current responses of our 4D model, relating these to the topology of the Bloch bands. We then propose experimental protocols, based on current or center-of-mass-drift measurements, to extract the topological second Chern number. Our proposal sets the stage for the exploration of novel topological phases in higher dimensions.
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Affiliation(s)
- H M Price
- INO-CNR BEC Center and Dipartimento di Fisica, Università di Trento, I-38123 Povo, Italy
| | - O Zilberberg
- Institute for Theoretical Physics, ETH Zurich, 8093 Zürich, Switzerland
| | - T Ozawa
- INO-CNR BEC Center and Dipartimento di Fisica, Università di Trento, I-38123 Povo, Italy
| | - I Carusotto
- INO-CNR BEC Center and Dipartimento di Fisica, Università di Trento, I-38123 Povo, Italy
| | - N Goldman
- CENOLI, Faculté des Sciences, Université Libre de Bruxelles (U.L.B.), B-1050 Brussels, Belgium
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41
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Labouvie R, Santra B, Heun S, Wimberger S, Ott H. Negative Differential Conductivity in an Interacting Quantum Gas. PHYSICAL REVIEW LETTERS 2015; 115:050601. [PMID: 26274404 DOI: 10.1103/physrevlett.115.050601] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Indexed: 06/04/2023]
Abstract
We report on the observation of negative differential conductivity (NDC) in a quantum transport device for neutral atoms employing a multimode tunneling junction. The system is realized with a Bose-Einstein condensate loaded in a one-dimensional optical lattice with high site occupancy. We induce an initial difference in chemical potential at one site by local atom removal. The ensuing transport dynamics are governed by the interplay between the tunneling coupling, the interaction energy, and intrinsic collisions, which turn the coherent coupling into a hopping process. The resulting current-voltage characteristics exhibit NDC, for which we identify atom number-dependent tunneling as a new microscopic mechanism. Our study opens new ways for the future implementation and control of complex neutral atom quantum circuits.
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Affiliation(s)
- Ralf Labouvie
- Research Center OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany
- Graduate School Materials Science in Mainz, Staudinger Weg 9, 55128 Mainz, Germany
| | - Bodhaditya Santra
- Research Center OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Simon Heun
- Research Center OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Sandro Wimberger
- DiFeST, Università di Parma, Via G. P. Usberti 7/a, 43124 Parma, Italy
- INFN, Sezione di Milano Bicocca, Gruppo Collegato di Parma, 43124 Parma, Italy
| | - Herwig Ott
- Research Center OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany
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42
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Krinner S, Stadler D, Meineke J, Brantut JP, Esslinger T. Observation of a Fragmented, Strongly Interacting Fermi Gas. PHYSICAL REVIEW LETTERS 2015; 115:045302. [PMID: 26252691 DOI: 10.1103/physrevlett.115.045302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Indexed: 06/04/2023]
Abstract
We study the emergence of a fragmented state in a strongly interacting Fermi gas subject to a tunable disorder. We investigate its properties using a combination of high-resolution in situ imaging and conductance measurements. The fragmented state exhibits saturated density modulations, a strongly reduced density percolation threshold, lower than the average density, and a resistance equal to that of a noninteracting Fermi gas in the same potential landscape. The transport measurements further indicate that this state is connected to the superfluid state as disorder is reduced. We propose that the fragmented state consists of unpercolated islands of bound pairs, whose binding energy is enhanced by the disorder.
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Affiliation(s)
| | - David Stadler
- Department of Physics, ETH Zurich, 8093 Zurich, Switzerland
| | - Jakob Meineke
- Department of Physics, ETH Zurich, 8093 Zurich, Switzerland
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43
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Mendoza-Arenas JJ, Clark SR, Jaksch D. Coexistence of energy diffusion and local thermalization in nonequilibrium XXZ spin chains with integrability breaking. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 91:042129. [PMID: 25974460 DOI: 10.1103/physreve.91.042129] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Indexed: 06/04/2023]
Abstract
In this work we analyze the simultaneous emergence of diffusive energy transport and local thermalization in a nonequilibrium one-dimensional quantum system, as a result of integrability breaking. Specifically, we discuss the local properties of the steady state induced by thermal boundary driving in a XXZ spin chain with staggered magnetic field. By means of efficient large-scale matrix product simulations of the equation of motion of the system, we calculate its steady state in the long-time limit. We start by discussing the energy transport supported by the system, finding it to be ballistic in the integrable limit and diffusive when the staggered field is finite. Subsequently, we examine the reduced density operators of neighboring sites and find that for large systems they are well approximated by local thermal states of the underlying Hamiltonian in the nonintegrable regime, even for weak staggered fields. In the integrable limit, on the other hand, this behavior is lost, and the identification of local temperatures is no longer possible. Our results agree with the intuitive connection between energy diffusion and thermalization.
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Affiliation(s)
- J J Mendoza-Arenas
- Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - S R Clark
- Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
- Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543
| | - D Jaksch
- Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
- Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543
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44
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Kondov SS, McGehee WR, Xu W, DeMarco B. Disorder-induced localization in a strongly correlated atomic Hubbard gas. PHYSICAL REVIEW LETTERS 2015; 114:083002. [PMID: 25768762 DOI: 10.1103/physrevlett.114.083002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Indexed: 06/04/2023]
Abstract
We observe the emergence of a disorder-induced insulating state in a strongly interacting atomic Fermi gas trapped in an optical lattice. This closed quantum system, free of a thermal reservoir, realizes the disordered Fermi-Hubbard model, which is a minimal model for strongly correlated electronic solids. We observe disorder-induced localization of a metallic state through measurements of mass transport. By varying the lattice potential depth, we detect interaction-driven delocalization of the disordered insulating state. We also measure localization that persists as the temperature of the gas is raised. These behaviors are consistent with many-body localization, which is a novel paradigm for understanding localization in interacting quantum systems at nonzero temperature.
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Affiliation(s)
- S S Kondov
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - W R McGehee
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - W Xu
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - B DeMarco
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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45
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Observation of quantized conductance in neutral matter. Nature 2015; 517:64-7. [PMID: 25557712 DOI: 10.1038/nature14049] [Citation(s) in RCA: 141] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2014] [Accepted: 11/01/2014] [Indexed: 11/08/2022]
Abstract
In transport experiments, the quantum nature of matter becomes directly evident when changes in conductance occur only in discrete steps, with a size determined solely by Planck's constant h. Observations of quantized steps in electrical conductance have provided important insights into the physics of mesoscopic systems and have allowed the development of quantum electronic devices. Even though quantized conductance should not rely on the presence of electric charges, it has never been observed for neutral, massive particles. In its most fundamental form, it requires a quantum-degenerate Fermi gas, a ballistic and adiabatic transport channel, and a constriction with dimensions comparable to the Fermi wavelength. Here we report the observation of quantized conductance in the transport of neutral atoms driven by a chemical potential bias. The atoms are in an ultraballistic regime, where their mean free path exceeds not only the size of the transport channel, but also the size of the entire system, including the atom reservoirs. We use high-resolution lithography to shape light potentials that realize either a quantum point contact or a quantum wire for atoms. These constrictions are imprinted on a quasi-two-dimensional ballistic channel connecting the reservoirs. By varying either a gate potential or the transverse confinement of the constrictions, we observe distinct plateaux in the atom conductance. The conductance in the first plateau is found to be equal to the universal conductance quantum, 1/h. We use Landauer's formula to model our results and find good agreement for low gate potentials, with all parameters determined a priori. Our experiment lets us investigate quantum conductors with wide control not only over the channel geometry, but also over the reservoir properties, such as interaction strength, size and thermalization rate.
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46
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Goldman N, Juzeliūnas G, Öhberg P, Spielman IB. Light-induced gauge fields for ultracold atoms. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2014; 77:126401. [PMID: 25422950 DOI: 10.1088/0034-4885/77/12/126401] [Citation(s) in RCA: 179] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Gauge fields are central in our modern understanding of physics at all scales. At the highest energy scales known, the microscopic universe is governed by particles interacting with each other through the exchange of gauge bosons. At the largest length scales, our Universe is ruled by gravity, whose gauge structure suggests the existence of a particle-the graviton-that mediates the gravitational force. At the mesoscopic scale, solid-state systems are subjected to gauge fields of different nature: materials can be immersed in external electromagnetic fields, but they can also feature emerging gauge fields in their low-energy description. In this review, we focus on another kind of gauge field: those engineered in systems of ultracold neutral atoms. In these setups, atoms are suitably coupled to laser fields that generate effective gauge potentials in their description. Neutral atoms 'feeling' laser-induced gauge potentials can potentially mimic the behavior of an electron gas subjected to a magnetic field, but also, the interaction of elementary particles with non-Abelian gauge fields. Here, we review different realized and proposed techniques for creating gauge potentials-both Abelian and non-Abelian-in atomic systems and discuss their implication in the context of quantum simulation. While most of these setups concern the realization of background and classical gauge potentials, we conclude with more exotic proposals where these synthetic fields might be made dynamical, in view of simulating interacting gauge theories with cold atoms.
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Affiliation(s)
- N Goldman
- College de France, 11 place Marcelin Berthelot & Laboratoire Kastler Brossel, CNRS, UPMC, ENS, 24 rue Lhomond, 75005 Paris, France
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47
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Grenier C, Georges A, Kollath C. Peltier cooling of fermionic quantum gases. PHYSICAL REVIEW LETTERS 2014; 113:200601. [PMID: 25432033 DOI: 10.1103/physrevlett.113.200601] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Indexed: 06/04/2023]
Abstract
We propose a cooling scheme for fermionic quantum gases, based on the principles of the Peltier thermoelectric effect and energy filtering. The system to be cooled is connected to another harmonically trapped gas acting as a reservoir. The cooling is achieved by two simultaneous processes: (i) the system is evaporatively cooled, and (ii) cold fermions from deep below the Fermi surface of the reservoir are injected below the Fermi level of the system, in order to fill the "holes" in the energy distribution. This is achieved by a suitable energy dependence of the transmission coefficient connecting the system to the reservoir. The two processes can be viewed as simultaneous evaporative cooling of particles and holes. We show that both a significantly lower entropy per particle and faster cooling rate can be achieved in this way than by using only evaporative cooling.
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Affiliation(s)
- Ch Grenier
- Institute for Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland
| | - A Georges
- Collège de France, 11 place Marcelin Berthelot, 75005 Paris, France; Centre de Physique Théorique, Ecole Polytechnique, CNRS, 91128 Palaiseau Cedex, France; and DPMC, Université de Genève, CH-1211 Geneva, Switzerland
| | - C Kollath
- HISKP, University of Bonn, Nussallee 14-16, D-53115 Bonn, Germany
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48
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Jullien T, Roulleau P, Roche B, Cavanna A, Jin Y, Glattli DC. Quantum tomography of an electron. Nature 2014; 514:603-7. [PMID: 25355360 DOI: 10.1038/nature13821] [Citation(s) in RCA: 132] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 08/29/2014] [Indexed: 11/09/2022]
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49
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Papoular DJ, Pitaevskii LP, Stringari S. Fast thermalization and Helmholtz oscillations of an ultracold Bose gas. PHYSICAL REVIEW LETTERS 2014; 113:170601. [PMID: 25379907 DOI: 10.1103/physrevlett.113.170601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Indexed: 06/04/2023]
Abstract
We analyze theoretically the transport properties of a weakly interacting ultracold Bose gas enclosed in two reservoirs connected by a constriction. We assume that the transport of the superfluid part is hydrodynamic, and we describe the ballistic transport of the normal part using the Landauer-Büttiker formalism. Modeling the coupled evolution of the phase, atom number, and temperature mismatches between the reservoirs, we predict that Helmholtz (plasma) oscillations can be observed at nonzero temperatures below Tc. We show that, because of its strong compressibility, the Bose gas is characterized by a fast thermalization compared to the damping time for plasma oscillations, accompanied by a fast transfer of the normal component. This fast thermalization also affects the gas above Tc, where we present a comparison to the ideal fermionic case. Moreover, we outline the possible realization of a superleak through the inclusion of a disordered potential.
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Affiliation(s)
- D J Papoular
- INO-CNR BEC Center and Dipartimento di Fisica, Università di Trento, 38123 Povo, Italy
| | - L P Pitaevskii
- INO-CNR BEC Center and Dipartimento di Fisica, Università di Trento, 38123 Povo, Italy and Kapitza Institute for Physical Problems, Kosygina 2, 119334 Moscow, Russia
| | - S Stringari
- INO-CNR BEC Center and Dipartimento di Fisica, Università di Trento, 38123 Povo, Italy
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Chang R, Potnis S, Ramos R, Zhuang C, Hallaji M, Hayat A, Duque-Gomez F, Sipe JE, Steinberg AM. Observing the onset of effective mass. PHYSICAL REVIEW LETTERS 2014; 112:170404. [PMID: 24836224 DOI: 10.1103/physrevlett.112.170404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Indexed: 06/03/2023]
Abstract
The response of a particle in a periodic potential to an applied force is commonly described by an effective mass, which accounts for the detailed interaction between the particle and the surrounding potential. Using a Bose-Einstein condensate of (87)Rb atoms initially in the ground band of an optical lattice, we experimentally show that the initial response of a particle to an applied force is in fact characterized by the bare mass. Subsequently, the particle response undergoes rapid oscillations and only over time scales that are long compared to those of the interband dynamics is the effective mass observed to be an appropriate description. Our results elucidate the role of the effective mass on short time scales, which is relevant for example in the interaction of few-cycle laser pulses with dielectric and semiconductor materials.
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Affiliation(s)
- Rockson Chang
- Department of Physics and Institute of Optics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 1A7, Canada
| | - Shreyas Potnis
- Department of Physics and Institute of Optics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 1A7, Canada
| | - Ramon Ramos
- Department of Physics and Institute of Optics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 1A7, Canada
| | - Chao Zhuang
- Department of Physics and Institute of Optics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 1A7, Canada
| | - Matin Hallaji
- Department of Physics and Institute of Optics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 1A7, Canada
| | - Alex Hayat
- Department of Physics and Institute of Optics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 1A7, Canada and Department of Electrical Engineering, Technion, Haifa 32000, Israel
| | - Federico Duque-Gomez
- Department of Physics and Institute of Optics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 1A7, Canada
| | - J E Sipe
- Department of Physics and Institute of Optics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 1A7, Canada
| | - Aephraim M Steinberg
- Department of Physics and Institute of Optics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 1A7, Canada
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