Optimization performance of quantum Otto heat engines and refrigerators with squeezed thermal reservoirs

Abstract

We consider a quantum Otto cycle, consisting of two isentropic processes (quantum adiabatic processes) and two isochoric processes, operating between two squeezed thermal reservoirs. The influences of the squeezing degree on the optimization performance of quantum Otto heat engines and refrigerators are investigated. We demonstrate that under symmetric condition, the efficiency at maximum work output (EMW) of heat engines and the coefficient of performance (COP) at maximum χ∗ criterion of refrigerators are equal to Curzon–Ahlborn (CA) efficiency and CA COP, respectively. We also found that under asymmetric condition, the EMW of heat engines can be improved when the squeezing degree of hot thermal reservoir is greater than that of the cold thermal reservoir, while be reduced or even inhibited in the opposite condition. However, the COP at maximum χ∗ criterion of refrigerators can be enhanced when the squeezing degree of cold thermal reservoir is greater than that of the hot thermal reservoir, otherwise will be suppressed.