1
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Erdman PA, Noé F. Model-free optimization of power/efficiency tradeoffs in quantum thermal machines using reinforcement learning. PNAS NEXUS 2023; 2:pgad248. [PMID: 37593201 PMCID: PMC10427747 DOI: 10.1093/pnasnexus/pgad248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 07/13/2023] [Accepted: 07/25/2023] [Indexed: 08/19/2023]
Abstract
A quantum thermal machine is an open quantum system that enables the conversion between heat and work at the micro or nano-scale. Optimally controlling such out-of-equilibrium systems is a crucial yet challenging task with applications to quantum technologies and devices. We introduce a general model-free framework based on reinforcement learning to identify out-of-equilibrium thermodynamic cycles that are Pareto optimal tradeoffs between power and efficiency for quantum heat engines and refrigerators. The method does not require any knowledge of the quantum thermal machine, nor of the system model, nor of the quantum state. Instead, it only observes the heat fluxes, so it is both applicable to simulations and experimental devices. We test our method on a model of an experimentally realistic refrigerator based on a superconducting qubit, and on a heat engine based on a quantum harmonic oscillator. In both cases, we identify the Pareto-front representing optimal power-efficiency tradeoffs, and the corresponding cycles. Such solutions outperform previous proposals made in the literature, such as optimized Otto cycles, reducing quantum friction.
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Affiliation(s)
- Paolo A Erdman
- Department of Mathematics and Computer Science, Freie Universität Berlin, Arnimallee 6, 14195 Berlin, Germany
| | - Frank Noé
- Department of Mathematics and Computer Science, Freie Universität Berlin, Arnimallee 6, 14195 Berlin, Germany
- Microsoft Research AI4Science, Karl-Liebknecht Str. 32, 10178 Berlin, Germany
- Department of Physics, Freie Universität Berlin, Arnimallee 6, 14195 Berlin, Germany
- Department of Chemistry, Rice University, Houston, TX 77005, USA
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2
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Sur S, Ghosh A. Quantum Advantage of Thermal Machines with Bose and Fermi Gases. ENTROPY (BASEL, SWITZERLAND) 2023; 25:372. [PMID: 36832738 PMCID: PMC9955716 DOI: 10.3390/e25020372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Revised: 02/14/2023] [Accepted: 02/14/2023] [Indexed: 06/18/2023]
Abstract
In this article, we show that a quantum gas, a collection of massive, non-interacting, indistinguishable quantum particles, can be realized as a thermodynamic machine as an artifact of energy quantization and, hence, bears no classical analog. Such a thermodynamic machine depends on the statistics of the particles, the chemical potential, and the spatial dimension of the system. Our detailed analysis demonstrates the fundamental features of quantum Stirling cycles, from the viewpoint of particle statistics and system dimensions, that helps us to realize desired quantum heat engines and refrigerators by exploiting the role of quantum statistical mechanics. In particular, a clear distinction between the behavior of a Fermi gas and a Bose gas is observed in one dimension, rather than in higher dimensions, solely due to the innate differences in their particle statistics indicating the conspicuous role of a quantum thermodynamic signature in lower dimensions.
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Affiliation(s)
- Saikat Sur
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Arnab Ghosh
- Department of Chemistry, Indian Institute of Technology, Kanpur 208016, India
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3
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Sheng J, Yang C, Wu H. Nonequilibrium thermodynamics in cavity optomechanics. FUNDAMENTAL RESEARCH 2023; 3:75-86. [PMID: 38933566 PMCID: PMC11197698 DOI: 10.1016/j.fmre.2022.09.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 08/23/2022] [Accepted: 09/12/2022] [Indexed: 11/30/2022] Open
Abstract
Classical thermodynamics has been a great achievement in dealing with systems that are in equilibrium or near equilibrium. As an emerging field, nonequilibrium thermodynamics provides a general framework for understanding the nonequilibrium processes, particularly in small systems that are typically far-from-equilibrium and are dominated by thermal or quantum fluctuations. Cavity optomechanical systems hold great promise among the various experimental platforms for studying nonequilibrium thermodynamics owing to their high controllability, excellent mechanical performance, and ability to operate deep in the quantum regime. Here, we present an overview of the recent advances in nonequilibrium thermodynamics with cavity optomechanical systems. The experimental results in entropy production assessment, fluctuation theorems, heat transfer, and heat engines are highlighted.
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Affiliation(s)
- Jiteng Sheng
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, China
- Chongqing Key Laboratory of Precision Optics, Chongqing Institute of East China Normal University, Chongqing 401120, China
| | - Cheng Yang
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
| | - Haibin Wu
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, China
- Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
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4
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Nakahara M. Counterdiabatic formalism of shortcuts to adiabaticity. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2022; 380:20210272. [PMID: 36335939 DOI: 10.1098/rsta.2021.0272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 08/15/2022] [Indexed: 06/16/2023]
Abstract
A pedagogical introduction to counterdiabatic formalism of shortcuts to adiabaticity is given so that readers can access some of the more specialized articles in the rest of this theme issue without any barriers. A guide to references is given so that this article also serves as a mini-review. This article is part of the theme issue 'Shortcuts to adiabaticity: theoretical, experimental and interdisciplinary perspectives'.
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Affiliation(s)
- Mikio Nakahara
- Research Institute for Science and Technology, Kindai University, Higashiosaka, Osaka 577-8502, Japan
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5
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de Oliveira TR, Jonathan D. Efficiency gain and bidirectional operation of quantum engines with decoupled internal levels. Phys Rev E 2021; 104:044133. [PMID: 34781508 DOI: 10.1103/physreve.104.044133] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 09/27/2021] [Indexed: 11/07/2022]
Abstract
We present a mechanism for efficiency increase in quantum heat engines containing internal energy levels that do not couple to the external work sink. The gain is achieved by using these levels to channel heat in a direction opposite to the one dictated by the second law. No quantum coherence, quantum correlations or ergotropy are required. A similar mechanism allows the engine to run "in reverse" and still produce useful work. We illustrate these ideas using a simple quantum Otto cycle in a coupled-spin system. We find this engine also exhibits other counterintuitive phenomenology. For example, its efficiency may increase as the temperature difference between the heat baths decreases. Conversely, it may cease to operate if the hotter bath becomes too hot or the colder bath too cold.
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Affiliation(s)
- Thiago R de Oliveira
- Instituto de Física, Universidade Federal Fluminense, Gragoatá 24210-346, Niterói, RJ, Brazil
| | - Daniel Jonathan
- Instituto de Física, Universidade Federal Fluminense, Gragoatá 24210-346, Niterói, RJ, Brazil
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6
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Bernardo BDL. Relating heat and entanglement in strong-coupling thermodynamics. Phys Rev E 2021; 104:044111. [PMID: 34781427 DOI: 10.1103/physreve.104.044111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 09/27/2021] [Indexed: 11/07/2022]
Abstract
Explaining the influence of strong coupling in the dynamics of open quantum systems is one of the most challenging issues in the rapidly growing field of quantum thermodynamics. By using a particular definition of heat, we develop an approach to study the thermodynamics in the strong-coupling regime, which takes into account quantum resources such as coherence and entanglement. We apply the method to calculate the time-dependent thermodynamic properties of a system and an environment interacting via the generalized amplitude-damping channel. The results indicate that the transient imbalance between heat dissipated and heat absorbed that occurs in the process is responsible for the generation of system-environment entanglement.
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Affiliation(s)
- Bertúlio de Lima Bernardo
- Departamento de Física, Universidade Federal da Paraíba, 58051-900 João Pessoa, PB, Brazil and Departamento de Física, Universidade Federal de Campina Grande, Caixa Postal 10071, 58109-970 Campina Grande, PB, Brazil
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7
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Funo K, Lambert N, Nori F. General Bound on the Performance of Counter-Diabatic Driving Acting on Dissipative Spin Systems. PHYSICAL REVIEW LETTERS 2021; 127:150401. [PMID: 34678023 DOI: 10.1103/physrevlett.127.150401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 09/15/2021] [Indexed: 06/13/2023]
Abstract
Counter-diabatic driving (CD) is a technique in quantum control theory designed to counteract nonadiabatic excitations and guide the system to follow its instantaneous energy eigenstates, and hence has applications in state preparation, quantum annealing, and quantum thermodynamics. However, in many practical situations, the effect of the environment cannot be neglected, and the performance of the CD is expected to degrade. To arrive at general bounds on the resulting error of CD in this situation we consider a driven spin-boson model as a prototypical setup. The inequalities we obtain, in terms of either the Bures angle or the fidelity, allow us to estimate the maximum error solely characterized by the parameters of the system and the bath. By utilizing the analytical form of the upper bound, we demonstrate that the error can be systematically reduced through optimization of the external driving protocol of the system. We also show that if we allow a time-dependent system-bath coupling angle, the obtained bound can be saturated and realizes unit fidelity.
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Affiliation(s)
- Ken Funo
- Theoretical Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
| | - Neill Lambert
- Theoretical Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
| | - Franco Nori
- Theoretical Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
- RIKEN Center for Quantum Computing (RQC), Wako-shi, Saitama 351-0198, Japan
- Physics Department, The University of Michigan, Ann Arbor, Michigan 48109-1040, USA
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8
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Zhang X, Chen Y, Wu Z, Wang J, Fan J, Deng S, Wu H. Observation of a superradiant quantum phase transition in an intracavity degenerate Fermi gas. Science 2021; 373:1359-1362. [PMID: 34446446 DOI: 10.1126/science.abd4385] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Xiaotian Zhang
- State Key Laboratory of Precision Spectroscopy, School of Physics and Electronics Science, East China Normal University, Shanghai 200062, P. R. China
| | - Yu Chen
- Graduate School of China Academy of Engineering Physics, Beijing 100193, P. R. China
| | - Zemao Wu
- State Key Laboratory of Precision Spectroscopy, School of Physics and Electronics Science, East China Normal University, Shanghai 200062, P. R. China
| | - Juan Wang
- State Key Laboratory of Precision Spectroscopy, School of Physics and Electronics Science, East China Normal University, Shanghai 200062, P. R. China
| | - Jijie Fan
- State Key Laboratory of Precision Spectroscopy, School of Physics and Electronics Science, East China Normal University, Shanghai 200062, P. R. China
| | - Shujin Deng
- State Key Laboratory of Precision Spectroscopy, School of Physics and Electronics Science, East China Normal University, Shanghai 200062, P. R. China
| | - Haibin Wu
- State Key Laboratory of Precision Spectroscopy, School of Physics and Electronics Science, East China Normal University, Shanghai 200062, P. R. China.,NYU-ECNU Institute of Physics at NYU Shanghai, Shanghai 200062, P. R. China.,Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, P. R. China
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9
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Del Campo A. Probing Quantum Speed Limits with Ultracold Gases. PHYSICAL REVIEW LETTERS 2021; 126:180603. [PMID: 34018797 DOI: 10.1103/physrevlett.126.180603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Accepted: 03/31/2021] [Indexed: 06/12/2023]
Abstract
Quantum speed limits (QSLs) rule the minimum time for a quantum state to evolve into a distinguishable state in an arbitrary physical process. These fundamental results constrain a notion of distance traveled by the quantum state, known as the Bures angle, in terms of the speed of evolution set by nonadiabatic energy fluctuations. I theoretically propose how to measure QSLs in an ultracold quantum gas confined in a time-dependent harmonic trap. In this highly-dimensional system of continuous variables, quantum tomography is prohibited. Yet, QSLs can be probed whenever the dynamics is self-similar by measuring as a function of time the cloud size of the ultracold gas. This makes it possible to determine the Bures angle and energy fluctuations, as I discuss for various ultracold atomic systems.
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Affiliation(s)
- Adolfo Del Campo
- Department of Physics and Materials Science, University of Luxembourg, L-1511 Luxembourg, Luxembourg; Donostia International Physics Center, E-20018 San Sebastián, Spain; IKERBASQUE, Basque Foundation for Science, E-48013 Bilbao, Spain; Department of Physics, University of Massachusetts, Boston, Massachusetts 02125, USA and Theory Division, Los Alamos National Laboratory, MS-B213, Los Alamos, New Mexico 87545, USA
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10
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Chen JF, Li Y, Dong H. Simulating Finite-Time Isothermal Processes with Superconducting Quantum Circuits. ENTROPY (BASEL, SWITZERLAND) 2021; 23:353. [PMID: 33809653 PMCID: PMC8002232 DOI: 10.3390/e23030353] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/12/2021] [Accepted: 03/12/2021] [Indexed: 11/16/2022]
Abstract
Finite-time isothermal processes are ubiquitous in quantum-heat-engine cycles, yet complicated due to the coexistence of the changing Hamiltonian and the interaction with the thermal bath. Such complexity prevents classical thermodynamic measurements of a performed work. In this paper, the isothermal process is decomposed into piecewise adiabatic and isochoric processes to measure the performed work as the internal energy change in adiabatic processes. The piecewise control scheme allows the direct simulation of the whole process on a universal quantum computer, which provides a new experimental platform to study quantum thermodynamics. We implement the simulation on ibmqx2 to show the 1/τ scaling of the extra work in finite-time isothermal processes.
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Affiliation(s)
- Jin-Fu Chen
- Beijing Computational Science Research Center, Beijing 100193, China;
- Graduate School of China Academy of Engineering Physics, No. 10 Xibeiwang East Road, Haidian District, Beijing 100193, China;
| | - Ying Li
- Graduate School of China Academy of Engineering Physics, No. 10 Xibeiwang East Road, Haidian District, Beijing 100193, China;
| | - Hui Dong
- Graduate School of China Academy of Engineering Physics, No. 10 Xibeiwang East Road, Haidian District, Beijing 100193, China;
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11
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Chand S, Dasgupta S, Biswas A. Finite-time performance of a single-ion quantum Otto engine. Phys Rev E 2021; 103:032144. [PMID: 33862721 DOI: 10.1103/physreve.103.032144] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 03/02/2021] [Indexed: 06/12/2023]
Abstract
We study how a quantum heat engine based on a single trapped ion performs in finite time. The always-on thermal environment acts like the hot bath, while the motional degree of freedom of the ion plays the role of the effective cold bath. The hot isochoric stroke is implemented via the interaction of the ion with its hot environment, while a projective measurement of the internal state of the ion is performed as an equivalent to the cold isochoric stroke. The expansion and compression strokes are implemented via suitable change in applied magnetic field. We study in detail how the finite duration of each stroke affects the engine performance. We show that partial thermalization can in fact enhance the efficiency of the engine, due to the residual coherence, whereas faster expansion and compression strokes increase the inner friction and therefore reduce the efficiency.
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Affiliation(s)
- Suman Chand
- Department of Physics, Indian Institute of Technology Ropar, Rupnagar, Punjab 140001, India
| | - Shubhrangshu Dasgupta
- Department of Physics, Indian Institute of Technology Ropar, Rupnagar, Punjab 140001, India
| | - Asoka Biswas
- Department of Physics, Indian Institute of Technology Ropar, Rupnagar, Punjab 140001, India
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12
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Sgroi P, Palma GM, Paternostro M. Reinforcement Learning Approach to Nonequilibrium Quantum Thermodynamics. PHYSICAL REVIEW LETTERS 2021; 126:020601. [PMID: 33512184 DOI: 10.1103/physrevlett.126.020601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 12/18/2020] [Indexed: 06/12/2023]
Abstract
We use a reinforcement learning approach to reduce entropy production in a closed quantum system brought out of equilibrium. Our strategy makes use of an external control Hamiltonian and a policy gradient technique. Our approach bears no dependence on the quantitative tool chosen to characterize the degree of thermodynamic irreversibility induced by the dynamical process being considered, requires little knowledge of the dynamics itself, and does not need the tracking of the quantum state of the system during the evolution, thus embodying an experimentally nondemanding approach to the control of nonequilibrium quantum thermodynamics. We successfully apply our methods to the case of single- and two-particle systems subjected to time-dependent driving potentials.
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Affiliation(s)
- Pierpaolo Sgroi
- Dipartimento di Fisica e Chimica-Emilio Segré, Università degli Studi di Palermo, via Archirafi 36, I-90123 Palermo, Italy
- Centre for Theoretical Atomic, Molecular and Optical Physics, School of Mathematics and Physics, Queen's University Belfast, Belfast BT7 1NN, United Kingdom
| | - G Massimo Palma
- Dipartimento di Fisica e Chimica-Emilio Segré, Università degli Studi di Palermo, via Archirafi 36, I-90123 Palermo, Italy
- NEST, Istituto Nanoscienze-CNR, Piazza S. Silvestro 12, 56127 Pisa, Italy
| | - Mauro Paternostro
- Centre for Theoretical Atomic, Molecular and Optical Physics, School of Mathematics and Physics, Queen's University Belfast, Belfast BT7 1NN, United Kingdom
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13
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Insinga AR. The Quantum Friction and Optimal Finite-Time Performance of the Quantum Otto Cycle. ENTROPY (BASEL, SWITZERLAND) 2020; 22:E1060. [PMID: 33286828 PMCID: PMC7597134 DOI: 10.3390/e22091060] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/11/2020] [Accepted: 09/18/2020] [Indexed: 11/16/2022]
Abstract
In this work we considered the quantum Otto cycle within an optimization framework. The goal was maximizing the power for a heat engine or maximizing the cooling power for a refrigerator. In the field of finite-time quantum thermodynamics it is common to consider frictionless trajectories since these have been shown to maximize the work extraction during the adiabatic processes. Furthermore, for frictionless cycles, the energy of the system decouples from the other degrees of freedom, thereby simplifying the mathematical treatment. Instead, we considered general limit cycles and we used analytical techniques to compute the derivative of the work production over the whole cycle with respect to the time allocated for each of the adiabatic processes. By doing so, we were able to directly show that the frictionless cycle maximizes the work production, implying that the optimal power production must necessarily allow for some friction generation so that the duration of the cycle is reduced.
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Affiliation(s)
- Andrea R Insinga
- DTU Energy Conversion and Storage, Technical University of Denmark Anker Engelundsvej, Building 301, 2800 Kgs. Lyngby, Denmark
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14
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Watanabe G, Venkatesh BP, Talkner P, Hwang MJ, Del Campo A. Quantum Statistical Enhancement of the Collective Performance of Multiple Bosonic Engines. PHYSICAL REVIEW LETTERS 2020; 124:210603. [PMID: 32530647 DOI: 10.1103/physrevlett.124.210603] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2019] [Revised: 04/09/2020] [Accepted: 05/01/2020] [Indexed: 06/11/2023]
Abstract
We consider an ensemble of indistinguishable quantum machines and show that quantum statistical effects can give rise to a genuine quantum enhancement of the collective thermodynamic performance. When multiple indistinguishable bosonic work resources are coupled to an external system, the internal energy change of the external system exhibits an enhancement arising from permutation symmetry in the ensemble, which is absent when the latter consists of distinguishable work resources.
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Affiliation(s)
- Gentaro Watanabe
- Department of Physics and Zhejiang Institute of Modern Physics, Zhejiang University, Hangzhou, Zhejiang 310027, China
- Zhejiang Province Key Laboratory of Quantum Technology and Device, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | | | - Peter Talkner
- Institut für Physik, Universität Augsburg, Universitätsstraße 1, D-86135 Augsburg, Germany
| | - Myung-Joong Hwang
- Division of Natural Sciences, Duke Kunshan University, No. 8 Duke Avenue, Kunshan, Jiangsu 215316, China
- Institute for Theoretical Physics, Ulm University, Albert-Einstein Allee 11, D-89081 Ulm, Germany
| | - Adolfo Del Campo
- Donostia International Physics Center, E-20018 San Sebastián, Spain
- IKERBASQUE, Basque Foundation for Science, E-48013 Bilbao, Spain
- Department of Physics, University of Massachusetts, Boston, Massachusetts 02125, USA
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15
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Nonadiabatic Energy Fluctuations of Scale-Invariant Quantum Systems in a Time-Dependent Trap. ENTROPY 2020; 22:e22050515. [PMID: 33286287 PMCID: PMC7517006 DOI: 10.3390/e22050515] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 04/28/2020] [Accepted: 04/29/2020] [Indexed: 11/16/2022]
Abstract
We consider the nonadiabatic energy fluctuations of a many-body system in a time-dependent harmonic trap. In the presence of scale-invariance, the dynamics becomes self-similar and the nondiabatic energy fluctuations can be found in terms of the initial expectation values of the second moments of the Hamiltonian, square position, and squeezing operators. Nonadiabatic features are expressed in terms of the scaling factor governing the size of the atomic cloud, which can be extracted from time-of-flight images. We apply this exact relation to a number of examples: the single-particle harmonic oscillator, the one-dimensional Calogero-Sutherland model, describing bosons with inverse-square interactions that includes the non-interacting Bose gas and the Tonks-Girdardeau gas as limiting cases, and the unitary Fermi gas. We illustrate these results for various expansion protocols involving sudden quenches of the trap frequency, linear ramps and shortcuts to adiabaticity. Our results pave the way to the experimental study of nonadiabatic energy fluctuations in driven quantum fluids.
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16
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Li R, Wu Y, Rui Y, Li B, Jiang Y, Ma L, Wu H. Absolute Frequency Measurement of ^{6}Li D Lines with khz-Level Uncertainty. PHYSICAL REVIEW LETTERS 2020; 124:063002. [PMID: 32109124 DOI: 10.1103/physrevlett.124.063002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 12/03/2019] [Indexed: 06/10/2023]
Abstract
We report the precision measurement of the absolute frequencies, hyperfine splitting, and 2P fine structure splitting in cold atoms of ^{6}Li. Using the stabilized optical frequency comb and developed heterodyne detection technique, the photon shot-noise limited optical spectroscopy is achieved. The measurement of absolute frequencies of D_{1} lines is reached with an uncertainty of about 1 kHz, which is 1 order of magnitude more accurate than previous measurements. The hyperfine splitting of the D_{1} line and 2P fine structure splitting of ^{6}Li are 26.103 1 (14) and 10 052.780 4 (18) MHz, respectively, in agreement with recent theoretical calculations. Our results could provide a benchmark to test the theory at the higher precision and help to resolve large discrepancies among previous experiments.
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Affiliation(s)
- Rui Li
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, People's Republic of China
| | - Yuelong Wu
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, People's Republic of China
| | - Yang Rui
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, People's Republic of China
| | - Bo Li
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, People's Republic of China
| | - Yanyi Jiang
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, People's Republic of China
| | - Longsheng Ma
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, People's Republic of China
| | - Haibin Wu
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, People's Republic of China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, China
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17
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Chen JF, Sun CP, Dong H. Achieve higher efficiency at maximum power with finite-time quantum Otto cycle. Phys Rev E 2020; 100:062140. [PMID: 31962481 DOI: 10.1103/physreve.100.062140] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Indexed: 11/07/2022]
Abstract
The optimization of heat engines was intensively explored to achieve higher efficiency while maintaining the output power. However, most investigations were limited to a few finite-time cycles, e.g., the Carnot-like cycle, due to the complexity of the finite-time thermodynamics. In this paper, we propose a class of finite-time engine with quantum Otto cycle, and demonstrate a higher achievable efficiency at maximum power. The current model can be widely utilized, benefitting from the general C/τ^{2} scaling of extra work for a finite-time adiabatic process with long control time τ. We apply the adiabatic perturbation method to the quantum piston model and calculate the efficiency at maximum power, which is validated with an exact solution.
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Affiliation(s)
- Jin-Fu Chen
- Beijing Computational Science Research Center, Beijing 100193, China.,Graduate School of China Academy of Engineering Physics, No. 10 Xibeiwang East Road, Haidian District, Beijing 100193, China
| | - Chang-Pu Sun
- Beijing Computational Science Research Center, Beijing 100193, China.,Graduate School of China Academy of Engineering Physics, No. 10 Xibeiwang East Road, Haidian District, Beijing 100193, China
| | - Hui Dong
- Graduate School of China Academy of Engineering Physics, No. 10 Xibeiwang East Road, Haidian District, Beijing 100193, China
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18
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Chen JF, Sun CP, Dong H. Boosting the performance of quantum Otto heat engines. Phys Rev E 2019; 100:032144. [PMID: 31640026 DOI: 10.1103/physreve.100.032144] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Indexed: 11/07/2022]
Abstract
To optimize the performance of a heat engine in a finite-time cycle, it is important to understand the finite-time effect of thermodynamic processes. Previously, we have shown that extra work is needed to complete a quantum adiabatic process in finite time, and proved that the extra work follows a C/τ^{2} scaling for long control time τ. There the oscillating part of the extra work is neglected due to the complex energy-level structure of the particular quantum system. However, such oscillation of the extra work cannot be neglected in some quantum systems with simple energy-level structure, e.g., the two-level system or the quantum harmonic oscillator. In this paper, we build the finite-time quantum Otto engine on these simple systems, and find that the oscillating extra work leads to a jagged edge in the constraint relation between the output power and the efficiency. By optimizing the control time of the adiabatic processes, the oscillation in the extra work is utilized to enhance the maximum power and the efficiency. We further design special control schemes with the zero extra work at the specific control time. Compared to the linear control scheme, these special control schemes of the finite-time adiabatic process improve the maximum power and the efficiency of the finite-time Otto engine.
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Affiliation(s)
- Jin-Fu Chen
- Beijing Computational Science Research Center, Beijing 100193, China.,Graduate School of China Academy of Engineering Physics, No. 10 Xibeiwang East Road, Haidian District, Beijing, 100193, China
| | - Chang-Pu Sun
- Beijing Computational Science Research Center, Beijing 100193, China.,Graduate School of China Academy of Engineering Physics, No. 10 Xibeiwang East Road, Haidian District, Beijing, 100193, China
| | - Hui Dong
- Graduate School of China Academy of Engineering Physics, No. 10 Xibeiwang East Road, Haidian District, Beijing, 100193, China
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19
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Guff T, Daryanoosh S, Baragiola BQ, Gilchrist A. Power and efficiency of a thermal engine with a coherent bath. Phys Rev E 2019; 100:032129. [PMID: 31639983 DOI: 10.1103/physreve.100.032129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Indexed: 06/10/2023]
Abstract
We consider a quantum engine driven by repeated weak interactions with a heat bath of identical three-level atoms. This model was first introduced by Scully et al. [Science 299, 862 (2003)SCIEAS0036-807510.1126/science.1078955], who showed that coherence between the energy-degenerate ground states serves as a thermodynamic resource that allows operation of a thermal cycle with a coherence-dependent thermalization temperature. We consider a similar engine out of the quasistatic limit and find that the ground-state coherence also determines the rate of thermalization, therefore increasing the output power and the engine efficiency only when the thermalization temperature is reduced; revealing a more nuanced perspective of coherence as a resource. This allows us to optimize the output power by adjusting the coherence and relative stroke durations.
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Affiliation(s)
- Thomas Guff
- Centre for Engineered Quantum Systems, Department of Physics and Astronomy, Macquarie University, Sydney NSW 2113, Australia
| | - Shakib Daryanoosh
- Centre for Engineered Quantum Systems, Department of Physics and Astronomy, Macquarie University, Sydney NSW 2113, Australia
| | - Ben Q Baragiola
- Centre for Engineered Quantum Systems, Department of Physics and Astronomy, Macquarie University, Sydney NSW 2113, Australia
| | - Alexei Gilchrist
- Centre for Engineered Quantum Systems, Department of Physics and Astronomy, Macquarie University, Sydney NSW 2113, Australia
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20
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Klatzow J, Becker JN, Ledingham PM, Weinzetl C, Kaczmarek KT, Saunders DJ, Nunn J, Walmsley IA, Uzdin R, Poem E. Experimental Demonstration of Quantum Effects in the Operation of Microscopic Heat Engines. PHYSICAL REVIEW LETTERS 2019; 122:110601. [PMID: 30951320 DOI: 10.1103/physrevlett.122.110601] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 01/07/2019] [Indexed: 06/09/2023]
Abstract
The ability of the internal states of a working fluid to be in a coherent superposition is one of the basic properties of a quantum heat engine. It was recently predicted that in the regime of small engine action, this ability can enable a quantum heat engine to produce more power than any equivalent classical heat engine. It was also predicted that in the same regime, the presence of such internal coherence causes different types of quantum heat engines to become thermodynamically equivalent. Here, we use an ensemble of nitrogen vacancy centers in diamond for implementing two types of quantum heat engines, and experimentally observe both effects.
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Affiliation(s)
- James Klatzow
- Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - Jonas N Becker
- Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - Patrick M Ledingham
- Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - Christian Weinzetl
- Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - Krzysztof T Kaczmarek
- Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
- Groupe de Physique Appliquée, Université de Genéve, CH-1211 Genéve, Switzerland
| | - Dylan J Saunders
- Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - Joshua Nunn
- Centre for Photonics and Photonic Materials, Department of Physics, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Ian A Walmsley
- Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - Raam Uzdin
- Fritz Haber Research Center for Molecular Dynamics, Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Eilon Poem
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 7610001, Israel
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21
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Çakmak B, Müstecaplıoğlu ÖE. Spin quantum heat engines with shortcuts to adiabaticity. Phys Rev E 2019; 99:032108. [PMID: 30999442 DOI: 10.1103/physreve.99.032108] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Indexed: 06/09/2023]
Abstract
We consider a finite-time quantum Otto cycle with single- and two spin-1/2 systems as its working medium. To mimic adiabatic dynamics at a finite time, we employ a shortcut-to-adiabaticity technique and evaluate the performance of the engine including the cost of the shortcut. We compare our results with the true adiabatic and nonadiabatic performances of the same cycle. Our findings indicate that the use of the shortcut-to-adiabaticity scheme significantly enhances the performance of the quantum Otto engine as compared to its adiabatic and nonadiabatic counterparts for different figures of merit.
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Affiliation(s)
- Barış Çakmak
- Department of Physics, Koç University, İstanbul, Sarıyer 34450, Turkey
- College of Engineering and Natural Sciences, Bahçeşehir University, Beşiktaş, Istanbul 34353, Turkey
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