Efficiency at Maximum Power of a Quantum Stirling Heat Engine

In both the classical and quantum fields, the efficiency at maximum power(EMP) of low-dissipation Carnot heat engines has been extensively studied. However, research on low-dissipation Stirling heat engines has never been done before. We use a two-level system as the working substance to construct a non regenerative quantum Stirling heat engine. In the range of low dissipation, we find that controlling the heat exchange of the working substance during the isochoric process can make the EMP upper bound of the Stirling engine exceed that of the Carnot engine. In addition, we also compare the efficiency of the heat engine in the high-temperature region and the low-temperature region in the case of symmetrical dissipation. The results obtained indicate that the heat engine operating in the high temperature region has an advantage over the low temperature region.