Finite-time performance of a quantum heat engine with a squeezed thermal bath

We consider the finite-time performance of a quantum Otto engine working between a hot squeezed and a cold thermal bath at inverse temperatures beta(h) and beta(c) (> beta(h)) with (k(B) 1)beta = 1/T . We derive the analytical expressions for work, efficiency, power, and power fluctuations, in which the squeezing parameter is involved. By optimizing the power output with respect to two frequencies, we derive the efficiency at maximum power as eta(mp) = (eta(gen)(C))(2)/[eta(gen)(C) - (1 - eta(gen)(C)) ln(1 - eta(gen)(C)], where the generalized Carnot efficiency eta(gen)(C) in the high-temperature or small squeezing limit simplifies to an analytic function of squeezing parameter gamma: eta(gen)(C) = 1 - beta(h)/[beta(c) cosh(2 gamma)]. Within the context of irreversible thermodynamics, we demonstrate that the expression of efficiency at maximum power satisfies a general form derived from nonlinear steady state heat engines. We show that, the power fluctuations are considerably increased, although the engine efficiency is enhanced by squeezing.