Coherence-enhanced efficiency of feedback-driven quantum engines

Brandner, Kay; Bauer, Michael; Schmid, M.; Seifert, Udo

doi:10.1088/1367-2630/17/6/065006

Cited by 92 publications

(75 citation statements)

References 54 publications

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“…Notice that the stateρ D has been chosen to maximize the work extracted, as indicated by our previous example and Eq. (8). The cycle is closed by putting the bosonic mode in contact with the cold thermal reservoir, and hence relaxing back tô ρ A without varying its frequency.…”

Section: A Optimal Otto Cyclementioning

confidence: 99%

“…Furthermore, motivated by the success of quantum information theory and the increasing control in preparation and manipulation of quantum states, the last decade has experienced a growing interest in understanding the thermodynamic implications of quantum features, such as quantum measurement [6][7][8][9], coherence [10][11][12][13], or quantum correlations [14][15][16][17][18][19]. In this context, inspired by the breakthrough work on the photoCarnot engine driven by quantum fuel proposed by Scully et al [10], different theoretical studies recently focused on the implications for work extraction introduced by nonequilibrium quantum reservoirs.…”

Section: Introductionmentioning

confidence: 99%

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Entropy production and thermodynamic power of the squeezed thermal reservoir

et al. 2016

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We analyze the entropy production and the maximal extractable work from a squeezed thermal reservoir. The nonequilibrium quantum nature of the reservoir induces an entropy transfer with a coherent contribution while modifying its thermal part, allowing work extraction from a single reservoir, as well as great improvements in power and efficiency for quantum heat engines. Introducing a modified quantum Otto cycle, our approach fully characterizes operational regimes forbidden in the standard case, such as refrigeration and work extraction at the same time, accompanied by efficiencies equal to unity.

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Section: A Optimal Otto Cyclementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Entropy production and thermodynamic power of the squeezed thermal reservoir

et al. 2016

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“…The measurement gives rise to some energy change E meas [36][37][38][39]: This is the only fuel for our engine, and no hot thermal bath is required (Fig. 1b).…”

Section: Figmentioning

confidence: 99%

Extracting work from quantum measurement in Maxwell demon engines

Elouard

Herrera-Martí

Huard

et al. 2017

Quantum Information and Measurement (QIM) 2017

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The essence of both classical and quantum engines is to extract useful energy (work) from stochastic energy sources, e.g. thermal baths. In Maxwell's demon engines, work extraction is assisted by a feedback control based on measurements performed by a demon, whose memory is erased at some nonzero energy cost. Here we propose a new type of quantum Maxwell's demon engine where work is directly extracted from the measurement channel, such that no heat bath is required. We show that in the Zeno regime of frequent measurements, memory erasure costs eventually vanish. Our findings provide a new paradigm to analyze quantum heat engines and work extraction in the quantum world.Introduction. Thermodynamics was originally developed to optimize machines that would extract work from reservoirs at various temperatures, by exploiting the transformations of some working agent. These machines may be assisted by a so-called Maxwell's demon, that exploits information acquired on the agent to enhance work extraction, at the energy expense of resetting the demon's memory. Maxwell's demons and Szilard's engines have been investigated in several theoretical proposals [1][2][3][4][5][6][7][8][9][10], including the thermodynamics of feedback control [11][12][13], and experimentally realized in various systems, e.g. Brownian particles [14,15], single electron transistors [16,17] and visible light [18]. Latest experiments have started addressing the regime where the working agent exhibits quantum coherences [2,19]. The potential extraction of work from quantum coherence leads to interesting open questions related to the energetic aspects of quantum information technologies [21][22][23][24][25][26]. Furthermore, novel designs for quantum engines, based on various kinds of quantum non-equilibrium reservoirs have been suggested [27][28][29][30][31][32] and experimentally investigated [33,34].Most quantum engines considered so far involve a hot reservoir, which is the primary source of energy. In this framework, measurements performed by the demon are practical steps where information is extracted, without changing the energy of the working agent. Ultimately, measurement (just like decoherence) can appear as a detrimental step of the thermodynamic cycle as it destroys quantum coherences, further preventing to extract work from them [35]. Here we adopt a different approach and show that measurement itself can be exploited as a fuel in a new kind of quantum engine. Originally here, the demon can perform measurements that are sensitive to states in an arbitrary basis of the system Hilbert space. It was recently shown [36-39] * Electronic address: alexia.auffeves@neel.cnrs.fr FIG. 1:Maxwell's demon assisted engines. a) Thermally driven engine. The working agent is a qubit of transition frequency ω0. A demon measuring in the qubit energy basis {|0 ; |1 } allows to convert the heat Q hot extracted from a bath into work Wext. The demon's memory is erased by some extra-work source at the minimal work cost Wer while the heat Q cold is evacuated in a ...

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“…On the level of thought experiments this discussion dates back all the way to Maxwell's demon (MD) 7 and then to Landauer's principle 8 . Till now, majority of the studies, both theoretically and in particular experimentally [9][10][11][12] , have been focusing on the classical regime; see, however, [13][14][15][16][17] and references therein for theories on quantum systems. The aim of this Letter is to present a simple and experimentally feasible quantum MD that can operate at the limit of thermodynamic efficiency.…”

mentioning

confidence: 99%

“…Estimating the integral of the evolution equation (16) for this q(t) with the exponential accuracy by the steepestdecent method, we find…”

mentioning

confidence: 99%

Maxwell's demon based on a single qubit

2016

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We propose and analyze Maxwell's demon based on a single qubit with avoided level crossing. Its operation cycle consists of adiabatic drive to the point of minimum energy separation, measurement of the qubit state, and conditional feedback. We show that the heat extracted from the bath at temperature T can ideally approach the Landauer limit of kBT ln 2 per cycle even in the quantum regime. Practical demon efficiency is limited by the interplay of Landau-Zener transitions and coupling to the bath. We suggest that an experimental demonstration of the demon is fully feasible using one of the standard superconducting qubits.

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Coherence-enhanced efficiency of feedback-driven quantum engines

Cited by 92 publications

References 54 publications

Entropy production and thermodynamic power of the squeezed thermal reservoir

Entropy production and thermodynamic power of the squeezed thermal reservoir

Extracting work from quantum measurement in Maxwell demon engines

Maxwell's demon based on a single qubit

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