Quantum thermodynamics and open-systems modeling

Kosloff, Ronnie

doi:10.1063/1.5096173

Cited by 89 publications

(70 citation statements)

References 192 publications

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“…Importantly, in several usual situations in thermodynamics, like in the context of spin baths [69,70], thermal machines or more generally when several thermal baths at different temperatures interact with the same system [71,72], the dissipative dynamics can be described by the interaction with an effective thermal bath at negative temperature. Therefore, to include such situations relevant for thermodynamics, we consider in the following that the bath interacting with the spin ensemble has a temperature (or apparent temperature) T B which can be either positive or negative.…”

Section: Collective Bath-induced Dissipationmentioning

confidence: 99%

Thermodynamics from indistinguishability: Mitigating and amplifying the effects of the bath

Latune

Sinayskiy

Petruccione

2019

Phys. Rev. Research

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Rich quantum effects emerge when several quantum systems are indistinguishable from the point of view of the bath they interact with. In particular, delocalised excitations corresponding to coherent superposition of excited states (reminiscent of double slit experiments or beam splitters in interferometers) appear and change drastically the dynamics and steady state of the systems. Such phenomena, which are central mechanisms of superradiance, present interesting properties for thermodynamics and potentially other quantum technologies. Indeed, a recent paper [C.L. Latune, I. Sinayskiy, F. Petruccione, Phys. Rev. A 99, 052105 (2019)] studies these properties in a pair of indistinguishable two-level systems and points out surprising effects of mitigation and amplification of the bath's action on the energy and entropy of the pair. Here, we generalise the study to ensembles of arbitrary number of spins of arbitrary size. We confirm that the previously uncovered mitigation and amplification effects remain, but also that they become more and more pronounced with growing number of spin and growing spin size. Moreover, we also investigate the free energy and the entropy production of the overall dissipation process and find dramatic reductions of irreversibility. The possibility of mitigating or amplifying the effects of the baths is highly desirable in quantum thermodynamics if one wants to optimise the use of the baths to enhance the performance of thermodynamic tasks. As illustrative application of these effects, we show explicitly the large power enhancements that can be obtained in cyclic thermal machines. The reduction of irreversibility is also a promising aspect since irreversibility is known to limit the performance of thermal machines. Beyond thermodynamics, the above findings might lead to interesting applications in state protection, quantum computational tasks, light harvesting devices, quantum biology, but also for the study of entropy production. Moreover, an experimental observation [J. M. Raimond, P. Goy, M. Gross, C. Fabre, and S. Haroche, Phys. Rev. Lett. 49, 117 (1982)] confirms that such effects are indeed within reach.observables J z and J 2 := J 2 x + J 2 y + J 2 z . Such eigenvectors are denoted by |J, m in reference to their associated eigenvalues,with −J ≤ m ≤ J and J ∈ [J 0 ; ns], where J 0 = 0 if s ≥ 1 and J 0 = 1/2 if s = 1/2 and n odd. A quick calculation shows that the natural basis contains (2s + 1) n elements whereas there are only (ns + 1) 2 (or (ns + 1/2)(ns + 3/2) when s = 1/2 and n is odd) different eigenvectors of J z and J 2 satisfying −J ≤ m ≤ J and J ∈ [J 0 ; ns]. Therefore, for n ≥ 3 degeneracies appear (some eigenvectors |J, m are repeated), meaning that different linear combinations of elements of the local basis |m 1 , ..., m n result in eigenstates of J z and J 2 with same eigenvalue J (total spin) and m (z-component of the spin). Then, we denote by |J, m i the degenerate eigenstates of J z and J 2 where the degeneracy index i runs from 1 to l J , integer which represents th...

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Section: Collective Bath-induced Dissipationmentioning

confidence: 99%

Thermodynamics from indistinguishability: Mitigating and amplifying the effects of the bath

Latune

Sinayskiy

Petruccione

2019

Phys. Rev. Research

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“…The use of the terms local and global could be misleading, since the local approach may lead to a good approximation to the exact dynamics for systems coupled to harmonic baths in certain parameter regimes for which the secular approximation fails [63,64]. However, for time-independent models thermodynamic consistency may not be ensured [62,65]. Remarkably, arXiv:1910.01600v1 [quant-ph] 3 Oct 2019 for time-dependent setups a detailed thermodynamic analysis may overcome this limitation [43,44,61].…”

Section: Introductionmentioning

confidence: 99%

Three-qubit refrigerator with two-body interactions

et al. 2020

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We propose a three-qubit setup for the implementation of a variety of quantum thermal machines where all heat fluxes and work production can be controlled. An important configuration that can be designed is that of an absorption refrigerator, extracting heat from the coldest reservoir without the need of external work supply. Remarkably, we achieve this regime by using only two-body interactions instead of the widely employed threebody interactions. This configuration could be more easily realised in current experimental setups. We model the open-system dynamics with both a global and a local master equation thermodynamic-consistent approach. Finally, we show how this model can be employed as a heat valve or thermal transistor, in which by varying the local field of one of the two qubits allows one to control and amplify the heat current between the other qubits.

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“…To date, the research on quantum thermodynamic cycles has mainly focused on the optimal path and optimal performance in one-stage HEs, including Carnot HEs [ 37 , 38 , 39 , 44 , 55 , 56 , 57 , 58 ], Brayton HEs [ 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 ], Otto HEs [ 46 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 ], Stirling HEs [ 45 , 77 , 78 , 79 , 80 , 81 ], and other HEs and systems [ 43 , 82 , 83 , 84 , 85 , 86 , 87 ]. Different optimization objects and different WMs, from endoreversible to irreversible QHE cycles, were also focused on; see the review articles [ 88 , 89 , 90 , 91 , 92 ].…”

Section: Introductionmentioning

confidence: 99%

Optimal Power and Efficiency of Multi-Stage Endoreversible Quantum Carnot Heat Engine with Harmonic Oscillators at the Classical Limit

Meng

Chen

2020

Entropy

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At the classical limit, a multi-stage, endoreversible Carnot cycle model of quantum heat engine (QHE) working with non-interacting harmonic oscillators systems is established in this paper. A simplified combined cycle, where all sub-cycles work at maximum power output (MPO), is analyzed under two types of combined form: constraint of cycle period or constraint of interstage heat current. The expressions of power and the corresponding efficiency under two types of combined constrains are derived. A general combined cycle, in which all sub-cycles run at arbitrary state, is further investigated under two types of combined constrains. By introducing the Lagrangian function, the MPO of two-stage combined QHE with different intermediate temperatures is obtained, utilizing numerical calculation. The results show that, for the simplified combined cycle, the total power decreases and heat exchange from hot reservoir increases under two types of constrains with the increasing number (N) of stages. The efficiency of the combined cycle decreases under the constraints of the cycle period, but keeps constant under the constraint of interstage heat current. For the general combined cycle, three operating modes, including single heat engine mode at low “temperature” (SM1), double heat engine mode (DM) and single heat engine mode at high “temperature” (SM2), appear as intermediate temperature varies. For the constraint of cycle period, the MPO is obtained at the junction of DM mode and SM2 mode. For the constraint of interstage heat current, the MPO keeps constant during DM mode, in which the two sub-cycles compensate each other.

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Quantum thermodynamics and open-systems modeling

Cited by 89 publications

References 192 publications

Thermodynamics from indistinguishability: Mitigating and amplifying the effects of the bath

Thermodynamics from indistinguishability: Mitigating and amplifying the effects of the bath

Three-qubit refrigerator with two-body interactions

Optimal Power and Efficiency of Multi-Stage Endoreversible Quantum Carnot Heat Engine with Harmonic Oscillators at the Classical Limit

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