Strong system-bath coupling effects in quantum absorption refrigerators

Ivander, Felix; Anto-Sztrikacs, Nicholas; Segal, Dvira

doi:10.1103/physreve.105.034112

Cited by 20 publications

(6 citation statements)

References 58 publications

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“…These expressions are expected to serve as the groundwork for understanding more complex systems (e.g. those amenable to strong coupling effects [84,85] and non-Markovian dynamics [86]).…”

Section: Method: Review Of the Redfield Equationmentioning

confidence: 99%

Quantum coherence-control of thermal energy transport: the V model as a case study

2022

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Whether genuine quantum effects, particularly quantum coherences, can offer an advantage to quantum devices is a topic of much interest. Here, we study a minimal model, the three-level V system coupled to two heat baths, and investigate the role of quantum coherences in heat transport in both the transient regime and in the nonequilibrium steady-state. In our model, energy is exchanged between the baths through two parallel pathways, which can be made distinct through the nondegeneracy of excited levels (energy splitting $\Delta$) and a control parameter $\alpha$, which adjusts the strength of one of the arms. Using a nonsecular quantum master equation of Redfield form, we succeed in deriving closed-form expressions for the quantum coherences and the heat current in the steady state limit for closely degenerate excited levels. By including three ingredients in our analysis: nonequilibrium baths, nondegeneracy of levels, and asymmetry of pathways, we show that quantum coherences are generated and sustained in the V model in the steady-state limit if three conditions, conjoining thermal and coherent effects are {\it simultaneously} met: (i) The two baths are held at different temperatures. (ii) Bath-induced pathways do not interfere destructively. (iii) Thermal rates do not mingle with the control parameter $\alpha$ to destroy interferences through an effective local equilibrium condition. Particularly, we find that coherences are maximized when the heat current is suppressed. Although we mainly focus on analytical results in the steady state limit, numerical simulations reveal that the transient behavior of coherences {\it contrasts} the steady-state limit: Large long-lived transient coherences vanish at steady state, while weak short-lived transient coherences survive, suggesting that different mechanisms are at play in these two regimes. Enhancing either the lifetime of transient coherences or their magnitude at steady state thus requires the control and optimization of different physical parameters.

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“…These expressions are expected to serve as the groundwork for understanding more complex systems (e.g. those amenable to strong coupling effects [84,85] and non-Markovian dynamics [86]).…”

Section: Method: Review Of the Redfield Equationmentioning

confidence: 99%

Quantum coherence-control of thermal energy transport: the V model as a case study

2022

Self Cite

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“…The starting point are the general forms previously obtained for the power in Eqs. (43), (45), (46) and for the heat current in Eq. (50).…”

Section: Weak Couplingmentioning

confidence: 99%

“…A rigorous treatment of energy exchanges and heat flows is thus required to properly model quantum thermal machines working out of equilibrium. For instance, the coupling, possibly strong, between quantum working medium and baths, can quite naturally induce non-Markovian effects, with backflow of information and energy from baths to working medium [25,[38][39][40][41][42][43][44][45][46], whose effects are often discarded in conventional approximation schemes [2-4, 15, 22, 41, 47, 48]. The question then arises, whether non-Markovian dynamics may constitute a useful thermodynamic resource.…”

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confidence: 99%

Non-Markovian dynamical heat engines

Cavaliere,

Carrega,

De Filippis

et al. 2022

Preprint

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We discuss whether, and under which conditions, it is possible to realize a heat engine simply by dynamically modulating the couplings between the quantum working medium and thermal reservoirs. For that purpose, we consider the paradigmatic model of a quantum harmonic oscillator, exposed to a minimal modulation, that is, a monochromatic driving of the coupling to only one of the thermal baths. We show that in this setup non-Markovianity of the bath is a necessary condition to obtain a heat engine. In addition, we identify suitable structured environments for the engine to approach the ideal Carnot efficiency. Our results open up new possibilities for the use of non-Markovian open quantum systems for the construction and optimization of quantum thermal machines.

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“…New experimental techniques [38][39][40][41][42][43][44] to access strongly coupled regime and recent theoretical progresses have now opened the avenue to consider the performance of thermal machines beyond weak coupling scenario [45][46][47][48][49][50][51][52][53][54]. In general, it has been observed that strong coupling effect reduces the performance of a thermal machine [46,51,52,55,56]. On the other hand, there are several studies [57][58][59][60] that showed that non-Markovian effect is actually beneficial for enhancing the performance even in the regime of weak coupling [46,57].…”

Section: Introductionmentioning

confidence: 99%

Strongly coupled quantum Otto cycle with single qubit bath

Chakraborty¹,

Das²,

Chruściński³

2022

Preprint

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We discuss a model of a closed quantum evolution of two-qubits where the joint Hamiltonian is so chosen that one of the qubits acts as a bath and thermalize the other qubit which is acting as the system. The corresponding exact master equation for the system is derived. Interestingly, for a specific choice of parameters the master equation takes the Gorini-Kossakowski-Lindblad-Sudarshan (GKLS) form with constant coefficients, representing pumping and damping of a single qubit system. Based on this model we construct an Otto cycle connected to a single qubit bath and study its thermodynamic properties. Our analysis goes beyond the conventional weak coupling scenario and illustrates the effects of finite bath including non-Markovianity. We find closed form expressions for efficiency (coefficient of performance), power (cooling power) for heat engine regime (refrigerator regime) for different modifications of the joint Hamiltonian.

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Strong system-bath coupling effects in quantum absorption refrigerators

Cited by 20 publications

References 58 publications

Quantum coherence-control of thermal energy transport: the V model as a case study

Quantum coherence-control of thermal energy transport: the V model as a case study

Non-Markovian dynamical heat engines

Strongly coupled quantum Otto cycle with single qubit bath

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