Quantum correlations and thermodynamic performances of two-qubit engines with local and common baths

Hewgill, Adam; Ferraro, Alessandro; Chiara, Gabriele De

doi:10.1103/physreva.98.042102

Cited by 79 publications

(69 citation statements)

References 70 publications

(103 reference statements)

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“…As an example, in the case of the two QHOs, [H I , a 1 ]=−òa 2 , so that a direct application of equation (43) leads to expression (17). From a practical point of view, equations (41) and (43) are our main results, as they offer general expressions that may be applied over a broad range of situations. These results generalize Barraʼs findings [88] to arbitrary bath and systemʼs structure.…”

Section: Thermodynamics Of the Repeated Interactions Methodsmentioning

confidence: 99%

“…For example, in the case of the two harmonic oscillators, equation (41) gives precisely the heat rate formula (16) that was used in section 2.…”

Section: Thermodynamics Of the Repeated Interactions Methodsmentioning

confidence: 99%

“…Moreover, with respect to the change in energy of the environments, we define the heat rates as t = -Ḋ Q H i E i , which then yields precisely equation (41).…”

Section: Appendix a The Lyapunov Equationmentioning

confidence: 99%

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Reconciliation of quantum local master equations with thermodynamics

et al. 2018

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The study of open quantum systems often relies on approximate master equations derived under the assumptions of weak coupling to the environment. However when the system is made of several interacting subsystems such a derivation is in many cases very hard. An alternative method, employed especially in the modeling of transport in mesoscopic systems, consists in using local master equations (LMEs) containing Lindblad operators acting locally only on the corresponding subsystem. It has been shown that this approach however generates inconsistencies with the laws of thermodynamics. In this paper we demonstrate that using a microscopic model of LMEs based on repeated collisions all thermodynamic inconsistencies can be resolved by correctly taking into account the breaking of global detailed balance related to the work cost of maintaining the collisions. We provide examples based on a chain of quantum harmonic oscillators whose ends are connected to thermal reservoirs at different temperatures. We prove that this system behaves precisely as a quantum heat engine or refrigerator, with properties that are fully consistent with basic thermodynamics. derivations are in general quite involved since they require knowledge of the full set of eigenvalues and eigenvectors of the system's Hamiltonian, something which quickly becomes prohibitive when the number of subsystems increases. Moreover, depending on the approximations employed, one may also arrive at equations which do not generate completely positive maps (the so-called Redfield equations [50]), or equations which contain unphysical heat currents [54]. For these reasons, microscopic derivations of master equations for systems connected to multiple environments still continues, nowadays, to be a topic of great interest.An alternative, more heuristic, approach consists in deriving a master equation for the individual subsystems, neglecting the interaction with the remaining subsystems. The resulting master equation will then contain only local jump operators describing exchanges between the environment E i and its corresponding subsystem S i . Such equations, which we shall henceforth refer to as LMEs (also frequently called boundarydriven master equations), are typically accurate when the dissipation rates are larger than the interaction between subsystems. Due to their computational simplicity, they have been extensively employed over the last two decades in the study of transport in non-equilibrium quantum systems [55][56][57][58][59][60][61][62][63][64][65][66][67][68][69][70][71][72][73].It turns out, however, that the nonlocal terms neglected in the LME may still lead to non-thermal steadystates [74] and play a significant role if the heat exchanges are small, even for weakly interacting parts. As a consequence, it has been found that LMEs may lead to apparent thermodynamic inconsistencies, as pointed out recently by Levy and Kosloff [75]. They have shown that the LME for two coupled quantum harmonic oscillators (QHO) may predict currents from a cold to a hot ther...

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Section: Thermodynamics Of the Repeated Interactions Methodsmentioning

confidence: 99%

“…For example, in the case of the two harmonic oscillators, equation (41) gives precisely the heat rate formula (16) that was used in section 2.…”

Section: Thermodynamics Of the Repeated Interactions Methodsmentioning

confidence: 99%

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Reconciliation of quantum local master equations with thermodynamics

et al. 2018

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“…Our second motivation for this analysis is to study the correspondence between classical and quantum heat engines (QHEs). In most of the studies so far, QHEs show exotic behavior owing to additional resources such as quantum coherence [15,29,[38][39][40][41][42][43], quantum entanglement [44][45][46][47][48], squeezed baths [49][50][51], among others. Otherwise, QHEs may show a remarkable similarity to macroscopic heat engines.…”

Section: Introductionmentioning

confidence: 99%

Three-level laser heat engine at optimal performance with ecological function

Singh

Johal

2019

Phys. Rev. E

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Although classical and quantum heat engines work on entirely different fundamental principles, there is an underlying similarity. For instance, the form of efficiency at optimal performance may be similar for both types of engines. In this work, we study a three-level laser quantum heat engine operating at maximum ecological function (EF) which represents a compromise between the power output and the loss of power due to entropy production. We derive analytic expressions for efficiency under the assumptions of strong matter-field coupling and high bath temperatures. Upper and lower bounds on the efficiency exist in case of extreme asymmetric dissipation when the ratio of systembath coupling constants at the hot and the cold contacts respectively approaches, zero or infinity. These bounds have been established previously for various classical models of Carnot-like engines. We conclude that while the engine produces at least 75% of the power output as compared with the maximum power conditions, the fractional loss of power is appreciably low in case of the engine operating at maximum EF, thus making this objective function relevant from an environmental point of view.

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“…It is nevertheless possible to exploit dissipation to create and stabilise entanglement [1][2][3][4][5][6][7][8][9][10][11][12][13]. This was studied in a variety of settings and physical systems [14][15][16][17][18][19][20][21][22][23][24] and dissipative entanglement generation using continuous driving was experimentally demonstrated, mainly for bipartite states [25][26][27][28].…”

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confidence: 99%

Autonomous multipartite entanglement engines

et al. 2020

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The generation of genuine multipartite entangled states is challenging in practice. Here we explore a new route to this task, via autonomous entanglement engines which use only incoherent coupling to thermal baths and time-independent interactions. We present a general machine architecture, which allows for the generation of a broad range of multipartite entangled states in a heralded manner. Specifically, given a target multiple-qubit state, we give a sufficient condition ensuring that it can be generated by our machine. We discuss the cases of Greenberger-Horne-Zeilinger, Dicke and cluster states in detail. These results demonstrate the potential of purely thermal resources for creating multipartite entangled states useful for quantum information processing.

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Quantum correlations and thermodynamic performances of two-qubit engines with local and common baths

Cited by 79 publications

References 70 publications

Reconciliation of quantum local master equations with thermodynamics

Reconciliation of quantum local master equations with thermodynamics

Three-level laser heat engine at optimal performance with ecological function

Autonomous multipartite entanglement engines

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