Beyond classical limits: Quantum superposition and inner friction in a quantum mechanical engine

We propose a quantum Otto engine operating through a cycle of two isochoric processes, where the working substance interacts with a single-mode radiation field, and two unitary strokes, during which the working substance is decoupled from the field. We investigate the influence of quantum superposition and quantum internal friction on the engine’s power output and efficiency, demonstrating that these quantum effects enhance both performance metrics. While these enhancements are accompanied by increased power fluctuations, we show that such fluctuations can be effectively mitigated through careful selection of control parameters. Our results reveal that the proposed quantum Otto engine can achieve performance regimes that are thermally inconceivable in classical systems, including surpassing the Otto efficiency limit and attaining 100% efficiency with nonzero power output.