Irreversible performance of a quantum harmonic heat engine

Rezek, Yair; Kosloff, Ronnie

doi:10.1088/1367-2630/8/5/083

Cited by 341 publications

(457 citation statements)

References 36 publications

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“…Otto cycle with a single harmonic oscillator (or a spin system) constituting the working medium of the engine is studied in different works [27,30,34,35,38,39]. Here we briefly review this.…”

Section: Single System As a Heat Enginementioning

confidence: 99%

Implications of Coupling in Quantum Thermodynamic Machines

Thomas

Banik

Ghosh

2017

Entropy

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Abstract:We study coupled quantum systems as the working media of thermodynamic machines. Under a suitable phase-space transformation, the coupled systems can be expressed as a composition of independent subsystems. We find that for the coupled systems, the figures of merit, that is the efficiency for engine and the coefficient of performance for refrigerator, are bounded (both from above and from below) by the corresponding figures of merit of the independent subsystems. We also show that the optimum work extractable from a coupled system is upper bounded by the optimum work obtained from the uncoupled system, thereby showing that the quantum correlations do not help in optimal work extraction. Further, we study two explicit examples; coupled spin-1/2 systems and coupled quantum oscillators with analogous interactions. Interestingly, for particular kind of interactions, the efficiency of the coupled oscillators outperforms that of the coupled spin-1/2 systems when they work as heat engines. However, for the same interaction, the coefficient of performance behaves in a reverse manner, while the systems work as the refrigerator. Thus, the same coupling can cause opposite effects in the figures of merit of heat engine and refrigerator.

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Section: Single System As a Heat Enginementioning

confidence: 99%

Implications of Coupling in Quantum Thermodynamic Machines

Thomas

Banik

Ghosh

2017

Entropy

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“…which is obtained using steps 1 and 3 in their sudden change limit [16,17]. Nevertheless, conventional (quasi) adiabatic processes lead to a very long cycle time, which yields a small engine power.…”

Section: Enhancement In Efficiency and Power Of A Prototype Micro mentioning

confidence: 99%

“…On the other hand, rapid steps 1 and 3 can generate higher power output but with the drawback of yielding a low engine efficiency η nonad . The balance between power and efficiency is of vast interest to heat engine designs [10,16]. Here we apply classical STA to the above-described Otto cycle in the classical domain.…”

Section: Enhancement In Efficiency and Power Of A Prototype Micro mentioning

confidence: 99%

Boosting work characteristics and overall heat-engine performance via shortcuts to adiabaticity: Quantum and classical systems

et al. 2013

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Under a general framework, shortcuts to adiabatic processes are shown to be possible in classical systems. We then study the distribution function of the work done on a small system initially prepared at thermal equilibrium. It is found that the work fluctuations can be significantly reduced via shortcuts to adiabatic processes. For example, in the classical case probabilities of having very large or almost zero work values are suppressed. In the quantum case negative work may be totally removed from the otherwise non-positive-definite work values. We also apply our findings to a micro Otto-cycle-based heat engine. It is shown that the use of shortcuts, which directly enhances the engine output power, can also increase the heat engine efficiency substantially, in both quantum and classical regimes.

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“…Therefore, the role of internal friction in quantum thermal devices has been devoted a considerable attention, recently [1,2,3,4,5,6,7,8,9,10,11,12,13,14]. As expected, the quantum friction is found to limit the performance of the quantum heat/refrigerator devices.…”

Section: Introductionmentioning

confidence: 91%

Irreversibility in a unitary finite-rate protocol: the concept of internal friction

2016

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Abstract. The concept of internal friction, a fully quantum mechanical phenomena, is investigated in a simple, experimentally accessible quantum system in which a spin-1/2 is driven by a transverse magnetic field in a quantum adiabatic process. The irreversible production of the waste energy due to the quantum friction is quantitatively analyzed in a forward-backward unitary transform of the system Hamiltonian by using the quantum relative entropy between the actual density matrix obtained in a parametric transformation and the one in a reversible adiabatic process. Analyzing the role of total transformation time and the different pulse control schemes on the internal friction reveal the non-monotone character of the internal friction as a function of the total protocol time and the possibility for almost frictionless solutions in finite-time transformations. IntroductionRecent advances in nanotechnology enable successful fabrication and control of systems in length scales where quantum features and fluctuations are dominant. If we are to use these quantum systems for useful purposes, such as heat to work conversion (i.e, as a quantum heat engine), we have to deal with the limitations imposed by quantum mechanics, such as quantum friction, on the thermodynamical transformations and cycles [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18]. Quantum friction is the hallmark of finite-time thermodynamical transformations. The infinitely long lasting ones are the reversible processes, which can drive the quantum systems from an equilibrium state to the another one. Reversible processes are, in general, optimal for the work output and the operational efficiency of the quantum heat engines, but they are in the expense of power output. For better powered quantum engines, one typically requires faster thermodynamical transformations, which are irreversible and drive the system outside of equilibrium states, leading to (unwanted) entropy production.

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Irreversible performance of a quantum harmonic heat engine

Cited by 341 publications

References 36 publications

Implications of Coupling in Quantum Thermodynamic Machines

Implications of Coupling in Quantum Thermodynamic Machines

Boosting work characteristics and overall heat-engine performance via shortcuts to adiabaticity: Quantum and classical systems

Irreversibility in a unitary finite-rate protocol: the concept of internal friction

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