Related papers: Efficiency fluctuations of a quantum Otto engine
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,…
We analyze the efficiency of the quantum Otto cycle applied to a superconducting cavity. We consider its description in terms of a full quantum scalar field in a one-dimensional cavity with a time dependent boundary condition that can be…
We study the Stoke's efficiency and its fluctuating properties in the case of a spatial asymmetric ratchet potential with a temporal asymmetric driving force from adiabatic to nonadiabatic regime. Our numerical investigations show that the…
A quantum Otto engine based on a three-dimensional harmonic oscillator is proposed. One of the modes of this oscillator functions as the working fluid, while the other two play the role of baths. The coupling between the working fluid and…
We formulate a protocol for a four-stroke quantum Otto engine that is capable of achieving superior performance when operating between two thermal reservoirs: one at a positive spin temperature and the other at an effective negative spin…
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…
In the quest for high-performance quantum thermal machines, looking for an optimal thermodynamic efficiency is only part of the issue. Indeed, at the level of quantum devices, fluctuations become extremely relevant and need to be taken into…
Quantum thermal machines make use of non-classical thermodynamic resources, one of which is interactions between elements of the quantum working medium. In this paper, we examine the performance of a quasi-static quantum Otto engine based…
We propose a quantum Otto cycle in a two spin-$1/2$ anisotropic XY model in a transverse external magnetic field. We first characterize the parameter regime that the working medium operates as an engine in the adiabatic regime. Then, we…
We use fast periodic control to realize finite-time Otto cycles exhibiting quantum advantage. Such periodic modulation of the working medium - bath interaction Hamiltonian during the thermalization strokes can give rise to non-Markovian…
We consider quantum heat engines that operate between nonequilibrium stationary reservoirs. We evaluate their maximum efficiency from the positivity of the entropy production and show that it can be expressed in terms of an effective…
Recent experimental breakthroughs produced the first nano heat engines that have the potential to harness quantum resources. An instrumental question is how their performance measures up against the efficiency of classical engines. For…
The power and efficiency of many-body heat engines can be boosted by performing cooperative non-adiabatic operations in contrast to the commonly used adiabatic implementations. Here, the key property relies on the fact that non-adiabaticity…
Optimal engine performances are accomplished by quantum effects. Here we explore two routes towards ideal engines, namely (1) quantum systems that operate as hybrid machines being able to perform more than one useful task and (2) the…
We investigate a stochastic heat engine based on an over-damped particle diffusing on the positive real axis in an externally driven time-periodic log-harmonic potential. The periodic driving is composed of two isothermal and two adiabatic…
In this work, we present a new framework for a relativistic quantum analouge of the classical Otto engine. Considering a single qubit as the working substance, we analyse its interaction with a massless quantum scalar field while undergoing…
We study a quantum thermal engine model for which the heat transfer law is determined by Einstein's theory of radiation. The working substance of the quantum engine is assumed to be a two-level quantum systems of which the constituent…
It was reported that, if and only if the specific heat, correlation length, and dynamical exponents $\alpha, \nu$ and $z$, fulfill the condition $\alpha-z\nu>0$, the phase transitions can enable a quantum heat engine to approach Carnot…
A three-level quantum system having two energy gaps presents a nontrivial working medium for a quantum heat engine. Our focus lies in understanding the constraints on the ability to modulate these gaps relative to the changes in probability…
We present an analytical study of the relativistic quantum Otto cycle driven by a time-dependent harmonic oscillator. By imposing an asymmetry on the two adiabatic processes of this cycle, we obtain distinct scenarios of sudden compression…