Quantum Otto engines with curvature-dependent efficiency: An analog model approach

Abstract

In this paper, we explore a quantum Otto cycle with a quantum harmonic oscillator on a circle as its working substance. Since the eigenenergies 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 consider two classical hot and cold thermal baths located in regions with different curvatures. By calculating the curvature-dependent work and heat in the Otto cycle, we emphasize the role of curvature in determining the thermal efficiency of the heat engine. Notably, we demonstrate that by adjusting the curvature difference between the bath locations, the engine's efficiency can approach the Carnot limit. © 2025 Elsevier B.V.