Internal dissipation and heat leaks in quantum thermodynamic cycles

Correa, Luis Alfonso; Palao, José P.; Alonso, Daniel

doi:10.1103/physreve.92.032136

Cited by 48 publications

(70 citation statements)

References 63 publications

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“…On the other hand, in the LD model, the symmetric dissipation is attached to η CA . If we use the α and t values of MP of the LD model and calculate the values of a c and a h associated with them (instead of calculating them according to Equations (28) and (29)), we can see whether they allow us to recover the correct value of σ hc that in the endoreversible model gives the CA efficiency or does not. That is, for Σ c = 1/2, Equations (20) and (21) reduce to…”

Section: Carnot-like Model Without Heat Leak (Endoreversible Model)mentioning

confidence: 99%

Carnot-Like Heat Engines Versus Low-Dissipation Models

González-Ayala

Roco

Medina

et al. 2017

Entropy

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Abstract:In this paper, a comparison between two well-known finite time heat engine models is presented: the Carnot-like heat engine based on specific heat transfer laws between the cyclic system and the external heat baths and the Low-Dissipation model where irreversibilities are taken into account by explicit entropy generation laws. We analyze the mathematical relation between the natural variables of both models and from this the resulting thermodynamic implications. Among them, particular emphasis has been placed on the physical consistency between the heat leak and time evolution on the one side, and between parabolic and loop-like behaviors of the parametric power-efficiency plots. A detailed analysis for different heat transfer laws in the Carnot-like model in terms of the maximum power efficiencies given by the Low-Dissipation model is also presented.

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Section: Carnot-like Model Without Heat Leak (Endoreversible Model)mentioning

confidence: 99%

Carnot-Like Heat Engines Versus Low-Dissipation Models

González-Ayala

Roco

Medina

et al. 2017

Entropy

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“…there is a heat leak which increases with the energy shift Δ [33]. The overall physical heat currents  ȧ and the performance of the device are then the result of the interplay of the different mechanisms related to each circuit.…”

Section: Motivation and Backgroundmentioning

confidence: 99%

“…Therefore the net heat current associated with these circuits always flows from the higher temperature bath to the lower temperature one. In the context of refrigerators and heat transformers these circuits are related to heat leaks that decrease the performance [33,34].…”

Section: Classification Of Circuitsmentioning

confidence: 99%

“…In particular, the attempt to interpret individually each term in the decomposition may lead to apparent negative entropy productions, although this problem can be avoided by a convenient choice of the fundamental circuits [29][30][31]. However, it has been shown that the diagnosis of the machine performance greatly benefits from considering the thermodynamic analysis of not only the fundamental but all the possible circuits in the graph [32][33][34]. A convenient approach is then Hill theory [35].…”

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confidence: 99%

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Relation between topology and heat currents in multilevel absorption machines

2017

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The steady state heat currents of continuous absorption machines can be decomposed into thermodynamically consistent contributions, each of them associated with a circuit in the graph representing the master equation of the thermal device. We employ this tool to study the functioning of absorption refrigerators and heat transformers with an increasing number of active levels. Interestingly, such an analysis is independent of the particular physical implementation (classical or quantum) of the device. We provide new insights into the understanding of scaling up thermal devices concerning both the performance and the magnitude of the heat currents. Indeed, it is shown that the performance of a multilevel machine is smaller or equal than the corresponding to the largest circuit contribution. Besides, the magnitude of the heat currents is well-described by a purely topological parameter which in general increases with the connectivity of the graph. Therefore, we conclude that for a fixed number of levels, the best of all different constructions of absorption machines is the one whose associated graph is as connected as possible, with the condition that the performance of all the contributing circuits is equal.The analysis of the thermodynamic quantities can be realized at different levels of description [24]. From a macroscopic point of view, where the relevant quantities are the bath temperatures and the physical (total) heat currents, to a microscopic description that considers in addition the device structure. This latter perspective is more and more relevant as the advance of the experimental techniques allows for the design and the manipulation of the device. A prominent tool for this microscopic analysis is graph theory, where the stochastic master equation for the populations is represented by a graph. Schnakenberg theory [25] is a popular approach that gives a decomposition of the total entropy production based on a set of fundamental circuits in the graph. Basically, Schnakenberg applies Kirchhoff's current laws to reduce the number of terms appearing in the entropy production, which may be highly beneficial for optimization procedures. It has been used for example in linear irreversible thermodynamics [26] and in the study of steady-state fluctuation theorems [27,28]. This method does not intend to associate an entropy production with each circuit. In particular, the attempt to interpret individually each term in the decomposition may lead to apparent negative entropy productions, although this problem can be avoided by a convenient choice of the fundamental circuits [29][30][31]. However, it has been shown that the diagnosis of the machine performance greatly benefits from considering the thermodynamic analysis of not only the fundamental but all the possible circuits in the graph [32][33][34]. A convenient approach is then Hill theory [35]. Schnakenberg and Hill theory assign the same affinity to each circuit, but the latter considers all the possible circuits and leads to thermodynamically consistent ent...

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“…Four eigenstates of the full, interacting Hamiltonian of the three-qubit refrigerator, indicating all possible bathinduced transitions in the global Lindblad approach. The cooling process can be interpreted as a pair of three-level refrigerators running in parallel[50].…”

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confidence: 99%

Quantum thermal absorption machines: refrigerators, engines and clocks

Mitchison

2019

Contemporary Physics

149

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The inexorable miniaturisation of technologies, the relentless drive to improve efficiency and the enticing prospect of boosting performance through quantum effects are all compelling reasons to investigate microscopic machines. Thermal absorption machines are a particularly interesting class of device that operate autonomously and use only heat flows to perform a useful task. In the quantum regime, this provides a natural setting in which to quantify the thermodynamic cost of various operations such as cooling, timekeeping or entanglement generation. This article presents a pedagogical introduction to the physics of quantum absorption machines, covering refrigerators, engines and clocks in detail.

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Internal dissipation and heat leaks in quantum thermodynamic cycles

Cited by 48 publications

References 63 publications

Carnot-Like Heat Engines Versus Low-Dissipation Models

Carnot-Like Heat Engines Versus Low-Dissipation Models

Relation between topology and heat currents in multilevel absorption machines

Quantum thermal absorption machines: refrigerators, engines and clocks

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