Coupled engine and refrigerator Driven in Nonlinear Jaynes-Cummings Model

With the Nonlinear Jaynes-Cummings model, we have studied heat engine and refrigerator, andresearched the effect of photon numbers, field-atom coupling constant, the nonlinear coupling constantof light field and nonlinear medium on the on processes of the Otto cycle. We discuss whether,and under which conditions, it is possible to realize a heat engine in Nonlinear Jaynes-Cummingsmodel. The enhancements in efficiency engine and refrigerator are explored in detail. We showthat in this setup photon numbers of the bath is a necessary condition to obtain a heat engine andrefrigerator. Our results open up new possibilities for the use of field-atom coupling constant forthe construction and optimization of quantum thermal machines.PACS numbers: 03.67.a, 03.65.Ta, 03.65.Ud.