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Yan LL, Bu JT, Zeng Q, Zhang K, Cui KF, Zhou F, Su SL, Chen L, Wang J, Chen G, Feng M. Experimental Verification of Demon-Involved Fluctuation Theorems. PHYSICAL REVIEW LETTERS 2024; 133:090402. [PMID: 39270181 DOI: 10.1103/physrevlett.133.090402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2024] [Accepted: 07/29/2024] [Indexed: 09/15/2024]
Abstract
The limit of energy saving in the control of small systems has recently attracted much interest due to the concept refinement of the Maxwell demon. Inspired by a newly proposed set of fluctuation theorems, we report the first experimental verification of these equalities and inequalities in an ultracold ^{40}Ca^{+} ion system, confirming the intrinsic nonequilibrium in the system due to involvement of the demon. Based on elaborately designed demon-involved control protocols, such as the Szilard engine protocol, we provide experimentally quantitative evidence of the dissipative information and observe tighter bounds of both the extracted work and the demon's efficacy than the limits predicted by the Sagawa-Ueda theorem. Our results substantiate a close connection between the physical nature of information and nonequilibrium processes at the microscale, which help to further understand the thermodynamic characteristics of information and the optimal design of nanoscale and smaller systems.
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Affiliation(s)
| | | | | | | | - K-F Cui
- Key Laboratory of Materials Physics, Ministry of Education, School of Physics and Laboratory of Zhongyuan Light, Zhengzhou University, Zhengzhou 450001, China
| | - F Zhou
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy of Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
| | - S-L Su
- Key Laboratory of Materials Physics, Ministry of Education, School of Physics and Laboratory of Zhongyuan Light, Zhengzhou University, Zhengzhou 450001, China
- Institute of Quantum Materials and Physics, Henan Academy of Sciences, Zhengzhou 450046, China
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2
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Cuzminschi M, Zubarev A, Iordache SM, Isar A. Influence of the seed of measurement on the work extracted in a quantum Szilard engine. iScience 2023; 26:108563. [PMID: 38162018 PMCID: PMC10755042 DOI: 10.1016/j.isci.2023.108563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 09/20/2023] [Accepted: 11/20/2023] [Indexed: 01/03/2024] Open
Abstract
We investigate the influence of the seed of measurement on the performance of a Szilard engine based on a two-mode Gaussian state evolving in a noisy channel. Quantum work is extracted by performing a positive operator-valued measurement (POVM) on one of the two modes, after which this mode reaches equilibrium with the environment. As the seed of measurement, we use a single-mode squeezed thermal state. We employ the Markovian Kossakowski-Lindblad master equation to determine the evolution in time of the considered open system and the quantum work is defined based on the Rényi entropy of order 2. We show that the extracted quantum work and information-work efficiency strongly depend on the characteristic parameters of the system (frequency, average thermal photons number, and squeezing), the noisy channel (temperature and squeezing of the bath), and the seed of measurement (average thermal photons number and strength of the measurement).
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Affiliation(s)
- Marina Cuzminschi
- Department of Theoretical Physics, “Horia Hulubei” National Institute for Physics and Nuclear Engineering, 07125 Magurele, Ilfov, Romania
- Faculty of Physics, University of Bucharest, 077125 Magurele, Ilfov, Romania
| | - Alexei Zubarev
- Plasma Physics and Nuclear Fusion Laboratory, National Institute for Laser, Plasma and Radiation Physics, 077125 Magurele, Ilfov, Romania
- Extreme Light Infrastructure, National Institute for Physics and Nuclear Engineering, 07125 Magurele, Ilfov, Romania
| | - Stefan-Marian Iordache
- Optospintronics Department, National Institute for Research and Development for Optoelectronics—INOE 2000, 077125 Magurele, Ilfov, Romania
| | - Aurelian Isar
- Department of Theoretical Physics, “Horia Hulubei” National Institute for Physics and Nuclear Engineering, 07125 Magurele, Ilfov, Romania
- Faculty of Physics, University of Bucharest, 077125 Magurele, Ilfov, Romania
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3
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Ruiz-Pino N, Villarrubia-Moreno D, Prados A, Cao-García FJ. Information in feedback ratchets. Phys Rev E 2023; 108:034112. [PMID: 37849167 DOI: 10.1103/physreve.108.034112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 08/17/2023] [Indexed: 10/19/2023]
Abstract
Feedback control uses the state information of the system to actuate on it. The information used implies an effective entropy reduction of the controlled system, potentially increasing its performance. How to compute this entropy reduction has been formally shown for a general system and has been explicitly computed for spatially discrete systems. Here, we address a relevant example of how to compute the entropy reduction by information in a spatially continuous feedback-controlled system. Specifically, we consider a feedback flashing ratchet, which constitutes a paradigmatic example for the role of information and feedback in the dynamics and thermodynamics of transport induced by the rectification of Brownian motion. A Brownian particle moves in a periodic potential that is switched on and off by a controller. The controller measures the position of the particle at regular intervals and performs the switching depending on the result of the measurement. This system reaches a long-time dynamical regime with a nonzero mean particle velocity, even for a symmetric potential. Here, we calculate the efficiency at maximum power in this long-time regime, computing all the required contributions. We show how the entropy reduction can be evaluated from the entropy of the non-Markovian sequence of control actions, and we also discuss the required sampling effort for its accurate computation. Moreover, the output power developed by the particle against an external force is investigated, which-for some values of the system parameters-is shown to become larger than the input power provided by the switching of the potential. The apparent efficiency of the ratchet thus becomes higher than one, if the entropy reduction contribution is not considered. This result highlights the relevance of including the entropy reduction by information in the thermodynamic balance of feedback-controlled devices, specifically when writing the second principle. The inclusion of the entropy reduction by information leads to a well-behaved efficiency over all the range of parameters investigated.
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Affiliation(s)
- Natalia Ruiz-Pino
- Física Teórica, Apartado de Correos 1065, Universidad de Sevilla, E-41080 Sevilla, Spain
- Departamento Estructura de la Materia, Física Térmica y Electrónica, Universidad Complutense de Madrid, Plaza de Ciencias, 1, 28040 Madrid, Spain
| | - Daniel Villarrubia-Moreno
- Departamento Estructura de la Materia, Física Térmica y Electrónica, Universidad Complutense de Madrid, Plaza de Ciencias, 1, 28040 Madrid, Spain
- Departamento de Matemáticas & Grupo Interdisciplinar de Sistemas Complejos (GISC), Universidad Carlos III de Madrid, Avenida Universidad 30, 28911 Leganés, Spain
| | - Antonio Prados
- Física Teórica, Apartado de Correos 1065, Universidad de Sevilla, E-41080 Sevilla, Spain
| | - Francisco J Cao-García
- Departamento Estructura de la Materia, Física Térmica y Electrónica, Universidad Complutense de Madrid, Plaza de Ciencias, 1, 28040 Madrid, Spain
- Instituto Madrileño de Estudios Avanzados en Nanociencia, IMDEA Nanociencia, Calle Faraday, 9, 28049 Madrid, Spain
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4
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Schmitt RK, Potts PP, Linke H, Johansson J, Samuelsson P, Rico-Pasto M, Ritort F. Information-to-work conversion in single-molecule experiments: From discrete to continuous feedback. Phys Rev E 2023; 107:L052104. [PMID: 37329008 DOI: 10.1103/physreve.107.l052104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Accepted: 04/10/2023] [Indexed: 06/18/2023]
Abstract
We theoretically investigate the extractable work in single molecule unfolding-folding experiments with applied feedback. Using a simple two-state model, we obtain a description of the full work distribution from discrete to continuous feedback. The effect of the feedback is captured by a detailed fluctuation theorem, accounting for the information aquired. We find analytical expressions for the average work extraction as well as an experimentally measurable bound thereof, which becomes tight in the continuous feedback limit. We further determine the parameters for maximal power or rate of work extraction. Although our two-state model only depends on a single effective transition rate, we find qualitative agreement with Monte Carlo simulations of DNA hairpin unfolding-folding dynamics.
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Affiliation(s)
- Regina K Schmitt
- Department of Physics and NanoLund, Lund University, Box 188, SE-221 00 Lund, Sweden
| | - Patrick P Potts
- Department of Physics and NanoLund, Lund University, Box 188, SE-221 00 Lund, Sweden
| | - Heiner Linke
- Department of Physics and NanoLund, Lund University, Box 188, SE-221 00 Lund, Sweden
| | - Jonas Johansson
- Department of Physics and NanoLund, Lund University, Box 188, SE-221 00 Lund, Sweden
| | - Peter Samuelsson
- Department of Physics and NanoLund, Lund University, Box 188, SE-221 00 Lund, Sweden
| | - Marc Rico-Pasto
- Department of Condensed Matter Physics, Small Biosystems Laboratory, Universitat de Barcelona, C/Marti i Franques 1, 08028 Barcelona, Spain
| | - Felix Ritort
- Department of Condensed Matter Physics, Small Biosystems Laboratory, Universitat de Barcelona, C/Marti i Franques 1, 08028 Barcelona, Spain
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5
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Salazar DSP. Thermodynamic uncertainty relation from involutions. Phys Rev E 2022; 106:L062104. [PMID: 36671130 DOI: 10.1103/physreve.106.l062104] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 12/09/2022] [Indexed: 06/17/2023]
Abstract
The thermodynamic uncertainty relation (TUR) is a lower bound for the variance of a current (over the mean squared) as a function of the average entropy production. Depending on the assumptions, one obtains different versions of the TUR. For instance, from the exchange fluctuation theorem, one obtains a corresponding exchange TUR. Alternatively, we show that TURs are a consequence of a very simple property: Every process s has only one conjugate s^{'}=m(s), where m is an involution, m(m(s))=s. This property allows the derivation of a general TUR without using any fluctuation theorem. As applications, we obtain the exchange TUR, the hysteretic TUR, a fluctuation-response inequality and a lower bound for the entropy production in terms of other nonequilibrium metrics.
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Affiliation(s)
- Domingos S P Salazar
- Unidade de Educação a Distância e Tecnologia, Universidade Federal Rural de Pernambuco, 52171-900 Recife, Pernambuco, Brazil
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6
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Bhattacharyya D, Jarzynski C. From a feedback-controlled demon to an information ratchet in a double quantum dot. Phys Rev E 2022; 106:064101. [PMID: 36671120 DOI: 10.1103/physreve.106.064101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Accepted: 11/15/2022] [Indexed: 06/17/2023]
Abstract
We present a simple strategy for constructing an information ratchet or memory-tape model of Maxwell's demon, from a feedback-controlled model. We illustrate our approach by converting the Annby-Andersson feedback-controlled double quantum dot model [Phys. Rev. B 101, 165404 (2020)2469-995010.1103/PhysRevB.101.165404] to a memory-tape model. We use the underlying network structure of the original model to design a set of bit interaction rules for the information ratchet. The new model is solved analytically in the limit of long interaction times. For finite-time interactions, semianalytical phase diagrams of operational modes are obtained. Stochastic simulations are used to verify theoretical results.
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Affiliation(s)
- Debankur Bhattacharyya
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, USA
| | - Christopher Jarzynski
- Institute for Physical Science and Technology, Department of Chemistry and Biochemistry, and Department of Physics, University of Maryland, College Park, Maryland 20742, USA
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7
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Paneru G, Dutta S, Pak HK. Colossal Power Extraction from Active Cyclic Brownian Information Engines. J Phys Chem Lett 2022; 13:6912-6918. [PMID: 35866740 PMCID: PMC9358709 DOI: 10.1021/acs.jpclett.2c01736] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 07/19/2022] [Indexed: 06/15/2023]
Abstract
Brownian information engines can extract work from thermal fluctuations by utilizing information. To date, the studies on Brownian information engines consider the system in a thermal bath; however, many processes in nature occur in a nonequilibrium setting, such as the suspensions of self-propelled microorganisms or cellular environments called an active bath. Here, we introduce an archetypal model for a Maxwell-demon type cyclic Brownian information engine operating in a Gaussian correlated active bath capable of extracting more work than its thermal counterpart. We obtain a general integral fluctuation theorem for the active engine that includes additional mutual information gained from the active bath with a unique effective temperature. This effective description modifies the generalized second law and provides a new upper bound for the extracted work. Unlike the passive information engine operating in a thermal bath, the active information engine extracts colossal power that peaks at the finite cycle period. Our study provides fundamental insights into the design and functioning of synthetic and biological submicrometer motors in active baths under measurement and feedback control.
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Affiliation(s)
- Govind Paneru
- Center
for Soft and Living Matter, Institute for
Basic Science (IBS), Ulsan 44919, Republic of Korea
- Department
of Physics, Ulsan National Institute of
Science and Technology, Ulsan 44919, Republic of Korea
| | - Sandipan Dutta
- Department
of Physics, Birla Institute of Technology
and Science, Pilani 333031, India
| | - Hyuk Kyu Pak
- Center
for Soft and Living Matter, Institute for
Basic Science (IBS), Ulsan 44919, Republic of Korea
- Department
of Physics, Ulsan National Institute of
Science and Technology, Ulsan 44919, Republic of Korea
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8
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Annby-Andersson B, Bakhshinezhad F, Bhattacharyya D, De Sousa G, Jarzynski C, Samuelsson P, Potts PP. Quantum Fokker-Planck Master Equation for Continuous Feedback Control. PHYSICAL REVIEW LETTERS 2022; 129:050401. [PMID: 35960579 DOI: 10.1103/physrevlett.129.050401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 06/24/2022] [Indexed: 06/15/2023]
Abstract
Measurement and feedback control are essential features of quantum science, with applications ranging from quantum technology protocols to information-to-work conversion in quantum thermodynamics. Theoretical descriptions of feedback control are typically given in terms of stochastic equations requiring numerical solutions, or are limited to linear feedback protocols. Here we present a formalism for continuous quantum measurement and feedback, both linear and nonlinear. Our main result is a quantum Fokker-Planck master equation describing the joint dynamics of a quantum system and a detector with finite bandwidth. For fast measurements, we derive a Markovian master equation for the system alone, amenable to analytical treatment. We illustrate our formalism by investigating two basic information engines, one quantum and one classical.
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Affiliation(s)
| | - Faraj Bakhshinezhad
- Physics Department and NanoLund, Lund University, Box 118, 22100 Lund, Sweden
| | - Debankur Bhattacharyya
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, USA
| | - Guilherme De Sousa
- Department of Physics, University of Maryland, College Park, Maryland 20742, USA
| | - Christopher Jarzynski
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, USA
| | - Peter Samuelsson
- Physics Department and NanoLund, Lund University, Box 118, 22100 Lund, Sweden
| | - Patrick P Potts
- Physics Department and NanoLund, Lund University, Box 118, 22100 Lund, Sweden
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
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9
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Cuzminschi M, Zubarev A, Isar A. Extractable quantum work from a two-mode Gaussian state in a noisy channel. Sci Rep 2021; 11:24286. [PMID: 34930993 PMCID: PMC8688490 DOI: 10.1038/s41598-021-03752-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Accepted: 12/09/2021] [Indexed: 11/10/2022] Open
Abstract
We study a Szilard engine based on a Gaussian state of a system consisting of two bosonic modes placed in a noisy channel. As the initial state of the system is taken an entangled squeezed thermal state, and the quantum work is extracted by performing a measurement on one of the two modes. We use the Markovian Kossakowski-Lindblad master equation for describing the time evolution of the open system and the quantum work definition based on the second order Rényi entropy to simulate the engine. We also study the information-work efficiency of the Szilard engine as a function of the system parameters. The efficiency is defined as the ratio of the extractable work averaged over the measurement angle and the erasure work, which is proportional to the information stored in the system. We show that the extractable quantum work increases with the temperature of the reservoir and the squeezing between the modes, average numbers of thermal photons and frequencies of the modes. The work increases also with the strength of the measurement, attaining the maximal values in the case of a heterodyne detection. The extractable work is decreasing by increasing the squeezing parameter of the noisy channel and it oscillates with the phase of the squeezed thermal reservoir. The efficiency mostly has a similar behavior with the extractable quantum work evolution. However information-work efficiency decreases with temperature, while the quantity of the extractable work increases.
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Affiliation(s)
- Marina Cuzminschi
- Department of Theoretical Physics, National Institute for Physics and Nuclear Engineering, 077125, Magurele-Bucharest, Romania
- Faculty of Physics, University of Bucharest, 077125, Magurele-Bucharest, Romania
| | - Alexei Zubarev
- Plasma Physics and Nuclear Fusion Department, National Institute for Laser, Plasma and Radiation Physics, 077125, Magurele-Bucharest, Romania.
| | - Aurelian Isar
- Department of Theoretical Physics, National Institute for Physics and Nuclear Engineering, 077125, Magurele-Bucharest, Romania
- Faculty of Physics, University of Bucharest, 077125, Magurele-Bucharest, Romania
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10
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Zeng Q, Wang J. New fluctuation theorems on Maxwell's demon. SCIENCE ADVANCES 2021; 7:7/23/eabf1807. [PMID: 34088664 PMCID: PMC8177699 DOI: 10.1126/sciadv.abf1807] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 04/20/2021] [Indexed: 06/12/2023]
Abstract
With increasing interest in the control of systems at the nano- and mesoscopic scales, studies have been focused on the limit of the energy dissipation in an open system by refining the concept of the Maxwell's demon. To uncover the underlying physical principle behind a system controlled by a demon, we prove a previously unexplored set of fluctuation theorems. These fluctuation theorems imply that there exists an intrinsic nonequilibrium state of the system, led by the nonnegative demon-induced dissipative information. A consequence of this analysis is that the bounds of both work and heat are tighter than the limits predicted by the Sagawa-Ueda theorem. We also suggest a possible experimental test of these work and heat bounds.
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Affiliation(s)
- Qian Zeng
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Changchun, Jilin 130022, China
| | - Jin Wang
- Departments of Chemistry and of Physics and Astronomy, State University of New York, Stony Brook, NY 11794-3400, USA.
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11
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Vo VT, Van Vu T, Hasegawa Y. Unified approach to classical speed limit and thermodynamic uncertainty relation. Phys Rev E 2021; 102:062132. [PMID: 33465987 DOI: 10.1103/physreve.102.062132] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 11/19/2020] [Indexed: 01/15/2023]
Abstract
The total entropy production quantifies the extent of irreversibility in thermodynamic systems, which is nonnegative for any feasible dynamics. When additional information such as the initial and final states or moments of an observable is available, it is known that tighter lower bounds on the entropy production exist according to the classical speed limits and the thermodynamic uncertainty relations. Here we obtain a universal lower bound on the total entropy production in terms of probability distributions of an observable in the time forward and backward processes. For a particular case, we show that our universal relation reduces to a classical speed limit, imposing a constraint on the speed of the system's evolution in terms of the Hatano-Sasa entropy production. Notably, the obtained classical speed limit is tighter than the previously reported bound by a constant factor. Moreover, we demonstrate that a generalized thermodynamic uncertainty relation can be derived from another particular case of the universal relation. Our uncertainty relation holds for systems with time-reversal symmetry breaking and recovers several existing bounds. Our approach provides a unified perspective on two closely related classes of inequality: classical speed limits and thermodynamic uncertainty relations.
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Affiliation(s)
- Van Tuan Vo
- Department of Information and Communication Engineering, Graduate School of Information Science and Technology, The University of Tokyo, Tokyo 113-8656, Japan
| | - Tan Van Vu
- Department of Information and Communication Engineering, Graduate School of Information Science and Technology, The University of Tokyo, Tokyo 113-8656, Japan
| | - Yoshihiko Hasegawa
- Department of Information and Communication Engineering, Graduate School of Information Science and Technology, The University of Tokyo, Tokyo 113-8656, Japan
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12
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Lee C, Ye H, Liu J, Zhang L. Information ratchet with time-varying temperature. Phys Rev E 2020; 101:042111. [PMID: 32422781 DOI: 10.1103/physreve.101.042111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 03/23/2020] [Indexed: 11/07/2022]
Abstract
We discuss a thermodynamic process with information and justify a general form of fluctuation relation. It shows that the fluctuation relation is valid whatever it is the temperature or Hamiltonian that drives the system out of equilibrium state. Based on the stochastic equation we obtain a nonequilibrium equality that involves both information and time-varying temperature. Through the processing of a harmonic system we demonstrate the validity of the equality by converting information into work. We also discuss the general second law of thermodynamics with time-varying temperature and verify its validity in an example by using information to reduce the total entropy.
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Affiliation(s)
- Chern Lee
- Yichun University, Yichun 336000, China
| | - Hai Ye
- Yichun University, Yichun 336000, China
| | | | - Li Zhang
- Pingxiang University, Pingxiang 337055, China
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13
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Potts PP, Samuelsson P. Thermodynamic uncertainty relations including measurement and feedback. Phys Rev E 2019; 100:052137. [PMID: 31869995 DOI: 10.1103/physreve.100.052137] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Indexed: 12/26/2022]
Abstract
Thermodynamic uncertainty relations quantify how the signal-to-noise ratio of a given observable is constrained by dissipation. Fluctuation relations generalize the second law of thermodynamics to stochastic processes. We show that any fluctuation relation directly implies a thermodynamic uncertainty relation, considerably increasing their range of applicability. In particular, we extend thermodynamic uncertainty relations to scenarios which include measurement and feedback. Since feedback generally breaks time-reversal invariance, the uncertainty relations involve quantities averaged over the forward and the backward experiment defined by the associated fluctuation relation. This implies that the signal-to-noise ratio of a given experiment can in principle become arbitrarily large as long as the corresponding backward experiment compensates, e.g., by being sufficiently noisy. We illustrate our results with the Szilard engine as well as work extraction by free energy reduction in a quantum dot.
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Affiliation(s)
- Patrick P Potts
- Physics Department and NanoLund, Lund University, Box 118, 22100 Lund, Sweden
| | - Peter Samuelsson
- Physics Department and NanoLund, Lund University, Box 118, 22100 Lund, Sweden
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