title: Efficiency at maximum power of a quantum heat engine based on two coupled oscillators.
abstract: We propose and theoretically investigate a system of two coupled harmonic oscillators as a heat engine. We show how these two coupled oscillators within undamped regime can be controlled to realize an Otto cycle that consists of two adiabatic and two isochoric processes. During the two isochores the harmonic system is embedded in two heat reservoirs at constant temperatures T(h) and T(c)(<T(h)), respectively, and it is tuned slowly along a protocol to realize an adiabatic process. To illustrate the performance in finite time of the quantum heat engine, we adopt the semigroup approach to model the thermal relaxation dynamics along the two isochoric processes, and we find the upper bound of efficiency at maximum power (EMP) η* to be a function of the Carnot efficiency η(C)(=1-T(c)/T(h)): η*≤η(+)≡η(C)(2)/[η(C)-(1-η(C))ln(1-η(C))], identical to those previously derived from ideal (noninteracting) microscopic, mesoscopic, and macroscopic systems.
authors.affiliation: Department of Physics, Nanchang University, Nanchang 330031, China.|State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Jianhui
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Physics, Nanchang University, Nanchang 330031, China.
authors.forename: Zhuolin
authors.initials: Z
authors.lastname: Ye
authors.affiliation: Department of Physics, Nanchang University, Nanchang 330031, China.
authors.forename: Yiming
authors.initials: Y
authors.lastname: Lai
authors.affiliation: Department of Physics, Nanchang University, Nanchang 330031, China.
authors.forename: Weisheng
authors.initials: W
authors.lastname: Li
authors.affiliation: Department of Physics, Nanchang University, Nanchang 330031, China.
authors.forename: Jizhou
authors.initials: J
authors.lastname: He
mesh_terms: D006358:Hot Temperature; D008962:Models, Theoretical; D011789:Quantum Theory