title: Efficiency at maximum power output of quantum heat engines under finite-time operation.
abstract: We study the efficiency at maximum power, η(m), of irreversible quantum Carnot engines (QCEs) that perform finite-time cycles between a hot and a cold reservoir at temperatures T(h) and T(c), respectively. For QCEs in the reversible limit (long cycle period, zero dissipation), η(m) becomes identical to the Carnot efficiency η(C)=1-T(c)/T(h). For QCE cycles in which nonadiabatic dissipation and the time spent on two adiabats are included, the efficiency η(m) at maximum power output is bounded from above by η(C)/(2-η(C)) and from below by η(C)/2. In the case of symmetric dissipation, the Curzon-Ahlborn efficiency η(CA)=1-√(T(c)/T(h)) is recovered under the condition that the time allocation between the adiabats and the contact time with the reservoir satisfy a certain relation.
authors.affiliation: Department of Physics, Nanchang University, Nanchang 330031, China. physwjh@gmail.com
authors.forename: Jianhui
authors.initials: J
authors.lastname: Wang
authors.forename: Jizhou
authors.initials: J
authors.lastname: He
authors.forename: Zhaoqi
authors.initials: Z
authors.lastname: Wu
mesh_terms: D003198:Computer Simulation; D004735:Energy Transfer; D006358:Hot Temperature; D008962:Models, Theoretical; D011789:Quantum Theory; D013816:Thermodynamics