  We study the quantum mechanical generalization of force or pressure, and then
we extend the classical thermodynamic isobaric process to quantum mechanical
systems. Based on these efforts, we are able to study the quantum version of
thermodynamic cycles that consist of quantum isobaric process, such as quantum
Brayton cycle and quantum Diesel cycle. We also consider the implementation of
quantum Brayton cycle and quantum Diesel cycle with some model systems, such as
single particle in 1D box and single-mode radiation field in a cavity. These
studies lay the microscopic (quantum mechanical) foundation for Szilard-Zurek
single molecule engine.
