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Typical heat engines exhibit a kind of homotypy: The heat exchanges between a cyclic heat engine and its two heat reservoirs abide by the same function type; the forward and backward flows of an autonomous heat engine also conform to the…

Statistical Mechanics · Physics 2015-05-05 Shiqi Sheng , Z. C. Tu

We present the exact theory of quantum engines whose working medium is a network of driven oscillators performing an arbitrary cyclic process while coupled to thermal and nonthermal reservoirs. We show that when coupled to a single…

Quantum Physics · Physics 2022-04-29 Milton Aguilar , Juan Pablo Paz

We propose a simple classical dynamical model of a thermoelectric (or thermochemical) heat engine based on a pair of ideal gas containers connected by two unequal scattering channels. The model is solved analytically and it is shown that a…

Statistical Mechanics · Physics 2009-06-18 Martin Horvat , Tomaz Prosen , Giulio Casati

The Curzon-Ahlborn efficiency has long served as the definite upper bound for the thermal efficiency at maximum output power, and has thus shaped the development of finite-time thermodynamics. In this paper, we repeal the ruling consensus…

Statistical Mechanics · Physics 2017-08-16 Yann Apertet , Henni Ouerdane , Christophe Goupil , Philippe Lecoeur

We study bounds on ratios of fluctuations in steady-state time-reversal heat engines controlled by multi affinities. In the linear response regime, we prove that the relative fluctuations (precision) of the output current (power) is always…

Statistical Mechanics · Physics 2021-11-17 Sushant Saryal , Matthew Gerry , Ilia Khait , Dvira Segal , Bijay Kumar Agarwalla

The unavoidable irreversible losses of power in a heat engine are found to be of quantum origin. Following thermodynamic tradition a model quantum heat engine operating by the Otto cycle is analyzed. The working medium of the model is…

Quantum Physics · Physics 2009-11-13 Yair Rezek , Ronnie Kosloff

The construction of efficient thermal engines operating at finite times constitutes a fundamental and timely topic in nonequilibrium thermodynamics. We introduce a strategy for optimizing the performance of Brownian engines, based on a…

Statistical Mechanics · Physics 2021-08-04 C. E. Fernández Noa , Angel L. L. Stable , William G. C. Oropesa , Alexandre Rosas , C. E. Fiore

We identify the operational conditions for maximum power of a nanothermoelectric engine consisting of a single quantum level embedded between two leads at different temperatures and chemical potentials. The corresponding thermodynamic…

Statistical Mechanics · Physics 2010-03-01 Massimiliano Esposito , Katja Lindenberg , Christian Van den Broeck

The efficiency of an heat engine is traditionally defined as the ratio of its average output work over its average input heat. Its highest possible value was discovered by Carnot in 1824 and is a cornerstone concept in thermodynamics. It…

Statistical Mechanics · Physics 2015-06-19 Gatien Verley , Tim Willaert , Christian Van den Broeck , Massimiliano Esposito

Recent theoretical and experimental studies in quantum heat engines show that, in the quasi-static regime, it is possible to have higher efficiency than the limit imposed by Carnot, provided that engineered reservoirs are used. The…

Quantum Physics · Physics 2021-05-26 Rogério J. de Assis , J. S. Sales , Udson C. Mendes , Norton G. de Almeida

We formulate the power-efficiency constraint of Carnot-like heat engines as a geometric optimization problem in the plane of normalized branch dissipations. Efficiency contours are straight lines in this plane, so maximizing efficiency at…

Statistical Mechanics · Physics 2026-05-05 R. X. Zhai

Efficiency and power are two central measures of the performance of thermal machines. We here study the power-efficiency-stability trade-off in a finite-time quantum Carnot information engine, in which an information reservoir replaces the…

Quantum Physics · Physics 2025-09-08 Milton Aguilar , Cüneyt Ünal , Eric Lutz

We study a refrigerator model which consists of two $n$-level systems interacting via a pulsed external field. Each system couples to its own thermal bath at temperatures $T_h$ and $T_c$, respectively ($\theta\equiv T_c/T_h<1$). The…

Statistical Mechanics · Physics 2009-06-16 Armen E. Allahverdyan , Karen Hovhannisyan , Guenter Mahler

Based on quantum thermodynamic processes, we make a quantum-mechanical (QM) extension of the typical heat engine cycles, such as the Carnot, Brayton, Otto, and Diesel cycles, etc. The temperature is not included in these QM engine cycles,…

Statistical Mechanics · Physics 2013-02-05 Jianhui Wang , Yongli Ma , Jizhou He

Whether the strong coupling to thermal baths can improve the performance of quantum thermal machines remains an open issue under active debate. Here, we revisit quantum thermal machines operating with the quasi-static Carnot cycle and aim…

Statistical Mechanics · Physics 2024-04-10 Junjie Liu , Kenneth A. Jung

We introduce a simple two-level heat engine to study the efficiency in the condition of the maximum power output, depending on the energy levels from which the net work is extracted. In contrast to the quasi-statically operated Carnot…

Statistical Mechanics · Physics 2016-12-05 Sang Hoon Lee , Jaegon Um , Hyunggyu Park

We revisit the optimization of performance of finite-time Carnot machines satisfying the low-dissipation assumption. The standard procedure seeks to optimize an objective function, such as power output of the engine, over the durations of…

Statistical Mechanics · Physics 2019-11-06 Ramandeep S. Johal

Multilevel autonomous quantum thermal machines are discussed. In particular, we explore the relation between the size of the machine (captured by Hilbert space dimension), and the performance of the machine. Using the concepts of virtual…

Quantum Physics · Physics 2016-09-21 Ralph Silva , Gonzalo Manzano , Paul Skrzypczyk , Nicolas Brunner

We adopt a geometric approach to describe the performance of adiabatic quantum machines, operating under slow time-dependent driving and in contact to two or more reservoirs with a temperature bias during all the cycle. We show that the…

Quantum Physics · Physics 2022-03-29 Pablo Terren Alonso , Paolo Abiuso , Marti Perarnau-Llobet , Liliana Arrachea

We report the experimental realization of a single-atom heat engine. An ion is confined in a linear Paul trap with tapered geometry and driven thermally by coupling it alternately to hot and cold reservoirs. The output power of the engine…