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Following the result by Skrzypczyk et al., arXiv:1009.0865, that certain self-contained quantum thermal machines can reach Carnot efficiency, we discuss the functioning of self-contained quantum thermal machines and show, in a very general…

Quantum Physics · Physics 2010-09-15 Sandu Popescu

The proper definition of entropy is fundamental to the relationship between statistical mechanics and thermodynamics. It also plays a major role in the recent debate about the validity of the concept of negative temperature. In this paper,…

Statistical Mechanics · Physics 2015-11-18 Robert H. Swendsen

Quantum heat engines employ as working agents multi-level systems instead of gas-filled cylinders. We consider particularly two-level agents such as electrons immersed in a magnetic field. Work is produced in that case when the electrons…

Quantum Physics · Physics 2007-05-23 Jacques Arnaud , Laurent Chusseau , Fabrice Philippe

We investigate the thermodynamic behavior of open quantum systems through the Hamiltonian of Mean Force, focusing on two models: a two-qubit system interacting with a thermal bath and a Jaynes-Cummings Model without the rotating wave…

Quantum Physics · Physics 2025-09-03 Neha Pathania , Devvrat Tiwari , Subhashish Banerjee

We consider a thermodynamic machine in which the working fluid is a quantized harmonic oscillator that is controlled on timescales that are much faster than the oscillator period. We find that operation in this `fast' regime allows access…

Quantum Physics · Physics 2020-09-15 James S. Bennett , Lars S. Madsen , Halina Rubinsztein-Dunlop , Warwick P. Bowen

Thermodynamics is a branch of science blessed by an unparalleled combination of generality of scope and formal simplicity. Based on few natural assumptions together with the four laws, it sets the boundaries between possible and impossible…

Quantum Physics · Physics 2014-02-06 Luis A. Correa , José P. Palao , Daniel Alonso , Gerardo Adesso

Quantum thermal machines can perform useful tasks, such as delivering power, cooling, or heating. In this work, we consider hybrid thermal machines, that can execute more than one task simultaneously. We characterize and find optimal…

Quantum Physics · Physics 2023-03-07 Fabio Cavaliere , Luca Razzoli , Matteo Carrega , Giuliano Benenti , Maura Sassetti

The separation of internal energy into heat and work in quantum thermodynamics is a controversial issue for a long time, and we revisit and solve this problem in this work. It is shown that the Hamiltonian plays dual roles for a quantum…

Quantum Physics · Physics 2025-01-03 Tao Zhou , Jiangyang Pu , Xiaohua Wu

There are many exotic thermodynamic processes that are hard to study in nature. Here, we synthesize a structured environment to explore the extremes of thermodynamics. We present an engine running at extreme temperatures of above ten…

An open fully connected system of qubits at nonzero temperature is driven within a finite time interval along various paths in the space of its control parameters. The driving leads across finite-size precursors of first- and second-order…

Quantum Physics · Physics 2024-12-18 Felipe Matus , Pavel Cejnar

We consider a class of quantum heat engines consisting of two subsystems interacting via a unitary transformation and coupled to two separate baths at different temperatures $T_h > T_c$. The purpose of the engine is to extract work due to…

Statistical Mechanics · Physics 2009-11-13 Armen E. Allahverdyan , Ramandeep S. Johal , Guenter Mahler

We study the thermalization properties of one-dimensional open quantum systems coupled to baths at their boundary. The baths are driven to their thermal states via Lindblad operators, while the system undergoes Hamiltonian dynamics. We…

Strongly Correlated Electrons · Physics 2023-08-02 Cristian Zanoci , Yongchan Yoo , Brian Swingle

Assigning the variations of internal energy into heat or work contributions is a challenging task due to the fact that these properties are trajectory dependent. A number of proposals have been put forward for open quantum systems following…

Quantum Physics · Physics 2021-09-01 Adrián Juan-Delgado , Aurélia Chenu

We discuss a quantum refrigerator to increase the ground state probability of a target qubit whose energy difference between the ground and excited states is less than the thermal energy of the environment. We consider two types of quantum…

Quantum Physics · Physics 2022-10-07 Hideaki Okane , Shunsuke Kamimura , Shingo Kukita , Yasushi Kondo , Yuichiro Matsuzaki

The resource theory of thermal operations, an established model for small-scale thermodynamics, provides an extension of equilibrium thermodynamics to nonequilibrium situations. On a lattice of any dimension with any translation-invariant…

Thermal machines exploit interactions with multiple heat baths to perform useful tasks, such as work production and refrigeration. In the quantum regime, tasks with no classical counterpart become possible. Here, we consider the minimal…

Quantum Physics · Physics 2022-03-23 Jonatan Bohr Brask , Fabien Clivaz , Géraldine Haack , Armin Tavakoli

We use a near quantum limited detector to experimentally track individual quantum state trajectories of a driven qubit formed by the hybridization of a waveguide cavity and a transmon circuit. For each measured quantum coherent trajectory,…

Quantum Physics · Physics 2020-03-25 M. Naghiloo , D. Tan , P. M. Harrington , J. J. Alonso , E. Lutz , A. Romito , K. W. Murch

Once in its non-equilibrium steady state, a nanoscale system coupled to several heat baths may be thought-of as a quantum heat pump. Depending on the direction of its stationary heat flows it may function as e.g. a refrigerator or a heat…

Quantum Physics · Physics 2016-04-18 Luis A. Correa , Mohammad Mehboudi

Recent progress in the synthesis and processing of nano-structured materials and systems calls for an improved understanding of thermal properties on small length scales. In this context, the question whether thermodynamics and, in…

Materials Science · Physics 2007-05-23 M. Hartmann , G. Mahler , O. Hess

By reformulating the first law of thermodynamics in the fashion of quantum-mechanical operators on the parameter manifold, we propose a universal class of quantum heat engines (QHE) using the multi-level quantum system as the working…

Quantum Physics · Physics 2007-05-23 H. T. Quan , P. Zhang , C. P. Sun