Critical-point behavior of a measurement-based quantum heat engine

Chand, Suman; Biswas, Asoka

doi:10.1103/physreve.98.052147

Cited by 29 publications

(19 citation statements)

References 63 publications

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“…We then use these insights to design many-body heat engines that can operate at Carnot efficiency with finite power per constituent of the WS through a supraextensive scaling of C/τ eq (e.g. in a phase transition), in the spirit of [33,34] (see also [34][35][36][37]). We show that the optimal finite-time Carnot cycle leads to milder conditions for the critical exponents of the WS needed to reach Carnot efficiency when compared to [34].…”

Section: Introductionmentioning

confidence: 99%

Optimal Cycles for Low-Dissipation Heat Engines

2020

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We consider the optimization of a finite-time Carnot engine characterized by small dissipations. We show with a simple inequality that the optimal strategy is to perform infinitesimal cycles around a given working point, which can be thus chosen optimally. Remarkably, this optimal point is independent of the figure of merit combining power and efficiency that is being maximised. Furthermore, in the corresponding cycle the power output becomes proportional to the heat capacity of the working substance. Since the heat capacity can scale supra-extensively with the number of constituents of the engine (e.g. in a phase transition point), this enables us to design many-body heat engines reaching Carnot efficiency at finite power per constituent in the thermodynamic limit.

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Section: Introductionmentioning

confidence: 99%

Optimal Cycles for Low-Dissipation Heat Engines

2020

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“…Authors in Ref. [43] also model the WF with a N = 2 LMG Hamiltonian of essentially a non-interacting type. They demonstrate a similar feature as in Ref.…”

Section: Consequences and Relevance To Other Known Resultsmentioning

confidence: 99%

Collective performance of a finite-time quantum Otto cycle

2019

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We study the finite-time effects in a quantum Otto cycle where a collective spin system is used as the working fluid. Starting from a simple one-qubit system we analyze the transition to the limit cycle in the case of a finite-time thermalization. If the system consists of a large sample of independent qubits interacting coherently with the heat bath, the superradiant equilibration is observed. We show that this phenomenon can boost the power of the engine. Mutual interaction of qubits in the working fluid is modeled by the Lipkin-Meshkov-Glick Hamiltonian. We demonstrate that in this case the quantum phase transitions for the ground and excited states may have a strong negative effect on the performance of the machine. Reversely, by analyzing the work output we can distinguish between the operational regimes with and without a phase transition.

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“…The accord between quantum mechanics and thermodynamics is yet to fully unfold [ 1 , 2 , 3 ]. Its fundamental implications have inspired numerous proposals for thermal machines based on quantum working media [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 ]. Two major issues which are addressed in such proposals are as follows: What are the performance bounds of heat engines working in quantum regime and what are the thermodynamic properties of these quantum systems which control these bounds?…”

Section: Introductionmentioning

confidence: 99%

Quantum Heat Engines with Complex Working Media, Complete Otto Cycles and Heuristics

Johal

Mehta

2021

Entropy

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Quantum thermal machines make use of non-classical thermodynamic resources, one of which include interactions between elements of the quantum working medium. In this paper, we examine the performance of a quasi-static quantum Otto engine based on two spins of arbitrary magnitudes subject to an external magnetic field and coupled via an isotropic Heisenberg exchange interaction. It has been shown earlier that the said interaction provides an enhancement of cycle efficiency, with an upper bound that is tighter than the Carnot efficiency. However, the necessary conditions governing engine performance and the relevant upper bound for efficiency are unknown for the general case of arbitrary spin magnitudes. By analyzing extreme case scenarios, we formulate heuristics to infer the necessary conditions for an engine with uncoupled as well as coupled spin model. These conditions lead us to a connection between performance of quantum heat engines and the notion of majorization. Furthermore, the study of complete Otto cycles inherent in the average cycle also yields interesting insights into the average performance.

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Critical-point behavior of a measurement-based quantum heat engine

Cited by 29 publications

References 63 publications

Optimal Cycles for Low-Dissipation Heat Engines

Optimal Cycles for Low-Dissipation Heat Engines

Collective performance of a finite-time quantum Otto cycle

Quantum Heat Engines with Complex Working Media, Complete Otto Cycles and Heuristics

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