Work and quantum phase transitions: Quantum latency

Mascarenhas, Eduardo; Bragança, Helena; Dorner, Ross; Santos, Marcelo F.; Vedral, Vlatko; Modi, Kavan; Goold, John

doi:10.1103/physreve.89.062103

Cited by 65 publications

(78 citation statements)

References 34 publications

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“…A nice idea how to achieve the Carnot efficiency is to keep temperatures of both baths small T c , T h ≪ 1ω so the system is predominantly in the ground state, and set λ i to the corresponding value of the real level crossing. At this point, due to the thermal dissipators the ground state is doubly degenerate and therefore has nonzero entropy S = ln 2 which is used to extract maximal work [42,77]. We should also stress that in this lowtemperature setting the operational protocol can be fully replaced with a standard Otto cycle.…”

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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Section: Consequences and Relevance To Other Known Resultsmentioning

confidence: 99%

Collective performance of a finite-time quantum Otto cycle

2019

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“…This quantum thermodynamic approach has been recently applied to study dissipation and entropy production in a variety of models in many-body physics [21,22,23,24,25]. We explore applications of this approach to a simple model for cosmological expansion.…”

Section: Introductionmentioning

confidence: 99%

Quantum thermodynamics for a model of an expanding Universe

Liu

Goold

Fuentes

et al. 2016

Class. Quantum Grav.

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Abstract. We investigate the thermodynamical properties of quantum fields in curved spacetime. Our approach is to consider quantum fields in curved spacetime as a quantum system undergoing an out-of-equilibrium transformation. The non-equilibrium features are studied by using a formalism which has been developed to derive fluctuation relations and emergent irreversible features beyond the linear response regime. We apply these ideas to an expanding universe scenario, therefore avoiding assumptions on the relation between entropy and quantum matter. We provide a fluctuation theorem which allows us to understand particle production due to the expansion of the universe as an entropic increase. Our results pave the way towards a different understanding of the thermodynamics of relativistic and quantum systems in our universe.

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“…In its current form, our scheme is readily implementable using a variety of different experimental platforms such as trapped ions, as demonstrated here. One may also hope that the formalism outlined here may be extended to measure heat dissipated in many-body systems following various quench protocols, where interesting links with critical features are currently been explored [31]. Most importantly, we hope that our proposal will inspire the first experimental explorations of the relationship between energy and information in the quantum domain.…”

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confidence: 95%

Measuring the heat exchange of a quantum process

2014

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Very recently, interferometric methods have been proposed to measure the full statistics of work performed on a driven quantum system [R. Dorner et al. Phys. Rev. Lett. 110, 230601 (2013) and Mazzola et al. Phys. Rev. Lett. 110, 230602 (2013)]. The advantage of such schemes is that they replace the necessity to make projective measurements by performing phase estimation on an appropriately coupled ancilla qubit. These proposals are one possible route to the tangible experimental exploration of quantum thermodynamics, a subject which is the center of much current attention due to the current control of mesoscopic quantum systems. In this Rapid Communication we demonstrate that a modification of the phase estimation protocols can be used in order to measure the heat distribution of a quantum process. In addition we demonstrate how our scheme maybe implemented using ion trap technology. Our scheme should pave the way for the first experimental explorations of the Landauer principle and hence the intricate energy to information conversion in mesoscopic quantum systems.Introduction.-Landauer's principle states that the heat generation in an irreversible computation must always be greater than or equal to the information theoretic entropy change [1]. The result is undoubtedly one of the deepest results of modern day computer science and information theory, providing a definitive link between energy and information. So profound is the principle that Bennett used it in order to exorcise Maxwell's demon by attributing a minimum entropy production to the logically irreversible procedure of erasure [2].It is indeed surprising that, despite its simplicity, the Landauer principle has only just been verified experimentally [3,4]. In this experiment the mean heat of a single colloidal particle trapped in a double well-potential was measured. Performing the requisite erasure procedure by modulating the double well, the average dissipated heat was found to saturate the Landauer bound in the long time limit.Turning to quantum systems, experiments in this direction still need to be performed. Of course, the Landauer principle is expected to hold generally, irrespective of the underlying classical or quantum nature of the system. However, recent work by Reeb and Wolf [5] has demonstrated that, for finitedimensional quantum systems, the Landauer principle can be tighter by an amount which depends on the size of the thermal reservoir.Undoubtedly, any experiment which aims at exploring the fundamental energetic limits of information processing would need to measure the heat exchange in a fundamental process. The modern approach to the thermodynamics of small systems is the framework of stochastic energetics [6] whereby quantities such as heat and work are described by probability distributions. These distributions obey fluctuation relations which have been extensively explored, both theoretically and experimentally, since their inception [7]. The fluctuation relations, extended to the quantum mechanical domain [8][9][10], are a pro...

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Work and quantum phase transitions: Quantum latency

Cited by 65 publications

References 34 publications

Collective performance of a finite-time quantum Otto cycle

Collective performance of a finite-time quantum Otto cycle

Quantum thermodynamics for a model of an expanding Universe

Measuring the heat exchange of a quantum process

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