Breaking the limits of purification: Postselection enhances heat-bath algorithmic cooling

Goldberg, Aaron Z.; Heshami, Khabat

doi:10.48550/arxiv.2108.08853

Cited by 3 publications

(3 citation statements)

References 58 publications

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“…While emphasizing the disputed role of the causal inseparability as a resource [10,[15][16][17][18] is not a goal of this work, we intend to study how the coherent activation of the maps in the QSM allows to optimize certain thermodynamic tasks. Very recent work has addressed the implications that the QSM might have for the performance of cooling cycles [19][20][21] and work-extraction games [22]. In particular, when dealing with work extraction and heat dissipation resulting from quantum processes, a ention should be paid to the role played by quantum coherence present or created in the state of the work medium [23,24], which are crucial.…”

Section: Introductionmentioning

confidence: 99%

Work extraction from coherently activated maps via quantum switch

et al. 2022

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We characterize the impact that the application of two maps in a quantum-controlled order has on the process of work extraction via unitary cycles and its optimization. e control is based on the quantum switch model that applies maps in an order not necessarily compatible with the underlying causal structure and, in principle, can be implemented experimentally. First, we show that the activation of quantum maps through the quantum switch model always entails a non-negative gain in ergotropy compared to their consecutive application. We also establish a condition that the maps should ful ll in order to achieve a non-zero ergotropic gain. We then perform a thorough analysis of maps applied to a two-level system and provide general conditions for achieving a positive gain on the incoherent part of ergotropy. Our results are illustrated with several examples and applied to qubit and 𝑑-dimensional quantum systems. In particular, we demonstrate that a non-zero work can be extracted from a system thermalized by two coherently controlled reservoirs.

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Section: Introductionmentioning

confidence: 99%

Work extraction from coherently activated maps via quantum switch

et al. 2022

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“…Compared with operations occurring in a well-de ned order, the advent of quantum SWITCH has o ered advantages in a plethora of information processing tasks like channel discrimination [4], computation [5], classical and quantum communication [6][7][8][9], and others. In a similar spirit, the relevance of the quantum SWITCH in the domain of quantum thermodynamics has recently been observed in the framework of quantum cooling [10][11][12][13], boosted quantum battery charging [14], and thermodynamic work extraction games [15,16]. As regards the latter, quantum SWITCH of two thermal maps has been considered for extraction of the free energy amount of work from thermal states [15] as well as with respect to work extraction under a unitary cyclic evolution of a quantum system [16].…”

Section: Introductionmentioning

confidence: 94%

Activation of thermal states by quantum SWITCH-driven thermalization and its limits

Guha¹,

Roy²,

Simonov³

et al. 2022

Preprint

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Coherently controlled thermalization via the quantum SWITCH allows to activate the state of a work medium and, hence, extract a non-zero work. However, such thermalization puts certain constraints on extractable work with respect to the temperatures of the work medium and reservoirs. We analyze these constraints and the possible ways to go beyond them. We characterize the impact that entanglement between target and control has on ergotropy and highlight the role of the coherence present in the state of the work medium. Last but not least, some of the results are generalized to the case of 𝑁 -switch.

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“…Many theoretical and experimental developments followed these pioneering studies. Among these achievements, we can cite applications to thermodynamics [7][8][9][10][11], quantum nature of gravity [12][13][14], relativistic quantum information [15,16], foundations of quantum mechanics [17][18][19][20][21], communication theory [22][23][24], quantum computation [25,26] quantum metrology [27,28], and other information-theoretic tasks [29][30][31], just to mention a few recent ones. Recent experiments on these lines were also reported [32][33][34][35][36] (see also the review [37]).…”

Section: Introductionmentioning

confidence: 99%

Indefinite causal order is not always a resource for thermodynamic processes

Capela¹,

Verma²,

Costa³

et al. 2022

Preprint

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Indefinite causal order is a key feature involved in the study of quantum higher order transformations. Recently, intense research has been focused on possible advantages related to the lack of definite causal order of quantum processes. Quite often the quantum switch is claimed to provide advantages in information-theoretic and thermodynamic tasks. We address here the question whether indefinite causal order is a resource for quantum thermodynamics. Inspired by previous results in the literature taking free energy and ergotropy as the figures of merit, we propose a framework for properly comparing the thermodynamic value of processes by comparing higher order transformations of the same type, and show that for the tasks considered here indefinite causal order is not necessary for thermodynamic advantages. More specifically, we show that there is a non-Markovian process, a causally ordered higher-order transformation, outperforming the results obtained for the quantum switch. We also discuss a possible way to study the advantages that may arise from indefinite causal order in a general scenario.

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Breaking the limits of purification: Postselection enhances heat-bath algorithmic cooling

Cited by 3 publications

References 58 publications

Work extraction from coherently activated maps via quantum switch

Work extraction from coherently activated maps via quantum switch

Activation of thermal states by quantum SWITCH-driven thermalization and its limits

Indefinite causal order is not always a resource for thermodynamic processes

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