Impact of spatial curvature on quantum Otto engines

In this paper, we consider a quantum Otto cycle with a quantum harmonic oscillator on a circle as its working substance. Since the eigen-energies of this oscillator depend on the curvature of the circle, this model, as an analog model, enables us to investigate the curvature effects of the physical space on properties of quantum heat engines. We assume that two classical hot and cold thermal baths are located at places with different curvatures. We calculate the curvature-dependent work and heat in our Otto cycle with a particular emphasis on how curvature affects it's thermal efficiency. By adjusting the curvature difference between the locations of the thermal baths, we demonstrate that the efficiency of our heat engine can reach the Carnot limit.