Quantum refrigeration cycles using spin-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mfrac><mml:mrow><mml:mn>1</mml:mn></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:mfrac></mml:math>systems as the working substance

He, Jizhou; Chen, Jincan; Ben, Hua

doi:10.1103/physreve.65.036145

Cited by 137 publications

(96 citation statements)

References 25 publications

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“…where 10) quantifies the reaction of the spin on the collective operator of the bath, and where we denoted 11) for the quantum noise operator 2 . Recalling the standard relationŝ…”

Section: Heisenberg Equations and Their Exact Solutionmentioning

confidence: 99%

Work extraction in the spin-boson model

2005

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We show that work can be extracted from a two-level system (spin) coupled to a bosonic thermal bath. This is possible due to different initial temperatures of the spin and the bath, both positive (no spin population inversion) and is realized by means of a suitable sequence of sharp pulses applied to the spin. The extracted work can be of the order of the response energy of the bath, therefore much larger than the energy of the spin. Moreover, the efficiency of extraction can be very close to its maximum, given by the Carnot bound, at the same time the overall amount of the extracted work is maximal. Therefore, we get a finite power at efficiency close to the Carnot bound.The effect comes from the backreaction of the spin on the bath, and it survives for a strongly disordered (inhomogeneously broadened) ensemble of spins. It is connected with generation of coherences during the work-extraction process, and we derived it in an exactly solvable model. All the necessary general thermodynamical relations are derived from the first principles of quantum mechanics and connections are made with processes of lasing without inversion and with quantum heat engines.

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“…where 10) quantifies the reaction of the spin on the collective operator of the bath, and where we denoted 11) for the quantum noise operator 2 . Recalling the standard relationŝ…”

Section: Heisenberg Equations and Their Exact Solutionmentioning

confidence: 99%

Work extraction in the spin-boson model

2005

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“…Two types of devices have been studied: reciprocating engines utilizing the Otto and Carnot cycle and continuous engines resembling lasers and laser cooling devices. A reciprocating cycle is partitioned typically into four segments, two adiabats, where the working system is isolated from the environment, and two heat transfer segments, either isotherms for the Carnot cycle [12][13][14][15][16][17] or isochores for the Otto cycle [18][19][20][21][22][23][24][25][26][27][28][29][30][31]. The same cycles were then used as models for refrigerators [19,[32][33][34][35].…”

Section: Introductionmentioning

confidence: 99%

Quantum Thermodynamics: A Dynamical Viewpoint

Kosloff

2013

Entropy

742

836

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Quantum thermodynamics addresses the emergence of thermodynamic laws from quantum mechanics. The viewpoint advocated is based on the intimate connection of quantum thermodynamics with the theory of open quantum systems. Quantum mechanics inserts dynamics into thermodynamics, giving a sound foundation to finite-time-thermodynamics. The emergence of the 0-law, I-law, II-law and III-law of thermodynamics from quantum considerations is presented. The emphasis is on consistency between the two theories, which address the same subject from different foundations. We claim that inconsistency is the result of faulty analysis, pointing to flaws in approximations.

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“…A QHE converts heat into useful mechanical work from quantum working mediums, such as multilevel systems [15], harmonic oscillator systems [16,17,18,19], spins or coupled spins [20], optomechanical systems [21], relativistic particles [22] and so on. Many investigations have been carried out to explore various possible improvement of the heat engine that the efficiency of a QHE can surpass the efficiency of a classical Carnot heat engine, and a QHE can extract work from a single heat bath [23].…”

Section: Introductionmentioning

confidence: 99%

Non-Hermitian heat engine with all-quantum-adiabatic-process cycle

Sun¹,

Song²

2016

J. Phys. A: Math. Theor.

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Abstract. As a quantum device, a quantum heat engine (QHE) is described by a Hermitian Hamiltonian. However, since it is an open system, reservoirs have to be imposed phenomenologically without any description in the context of quantum mechanics. A nonHermitian system is expected to describe an open system which exchanges energy and particles with external reservoirs. Correspondingly, such an exchange can be adiabatic in the context of quantum mechanics. We first propose a non-Hermitian QHE by a concrete simple two-level system, which is an S = 1/2 spin in a complex external magnetic field. The non-Hermitian PTsymmetric Hamiltonian, as a self-contained one, describes both working medium and reservoirs. A heat-engine cycle is composed of completely quantum adiabatic processes. Surprisingly, the heat efficiency is obtained to be the same as that of Hermitian quantum Otto cycle. A classical analogue of this scheme is also presented. Our finding paves the way for revealing what the role of a non-Hermitian Hamiltonian plays in physics.

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Quantum refrigeration cycles using spin-12systems as the working substance

Cited by 137 publications

References 25 publications

Work extraction in the spin-boson model

Work extraction in the spin-boson model

Quantum Thermodynamics: A Dynamical Viewpoint

Non-Hermitian heat engine with all-quantum-adiabatic-process cycle

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