  We investigate the quantum thermodynamic cycle of a quantum heat engine
carrying out an Otto thermodynamic cycle. We use the thermal properties of a
moving heat bath with relativistic velocity with respect to the cold bath. As a
working medium, we use a two-level system and a harmonic oscillator that
interact with a moving heat bath and a static cold bath. In the current work,
the quantum heat engine is studied in the high and low temperatures regime.
Using quantum thermodynamics and the theory of open quantum system we obtain
the total produced work, the efficiency and the efficiency at maximum power.
The maximum efficiency of the Otto quantum heat engine depends only on the
ratio of the minimum and maximum energy gaps. On the contrary, the efficiency
at maximum power and the extracted work decreases with the velocity since the
motion of the heat bath has an energy cost for the quantum heat engine.
Furthermore, the efficiency at maximum power depends on the nature of the
working medium.
