Quantum heat engines, compared to their classical counterparts, offer many advantages due to quantum effects. The study of different cycle modes contributes to the improvement of heat engine efficiency. In this paper, based on a quantum hybrid heat engine, we compare three cycle modes involving Bell-type quantum weak measurement (without observing the results) and two heat baths at different temperatures, where quantum weak measurements play the role of heat source. Thus, there are two types of heat sources and three processes involving heat absorption or release in our model. In other words, we study a multi-stroke quantum hybrid heat engine. Moreover, we further investigate three types of cycle modes using a working substance composed of a three-particle XXZ spin chain. In the adiabatic stroke, we select three Hamiltonian parameters and vary them adiabatically from their initial to final values, comparing their effects on engine efficiency. In particular, we examine how the ordering of the weak-measurement stroke and the adiabatic stroke influences heat absorption, heat release, and engine efficiency. Additionally, we analyze the impact of the high-temperature bath’s temperature and the weak-measurement strength on the engine efficiency.
Chao-Quan Wang (Fri,) studied this question.