Work production of quantum rotor engines

TL;DR

This paper analyzes the work performance of quantum rotor heat engines using models based on heat flow and temperature cycling, connecting physical and information-theoretic work concepts.

Contribution

It introduces a comprehensive thermodynamical framework for quantum rotor engines, comparing ergotropy and intrinsic work, and relates them to energy output and quantum signatures.

Findings

Ergotropy aligns with the intuitive notion of work as directed motion.

Work definitions are consistent with energy output under optimal conditions.

Quantum signatures like angular momentum quantization are observed.

Abstract

We study the mechanical performance of quantum rotor heat engines in terms of common notions of work using two prototypical models: a mill driven by the heat flow from a hot to a cold mode, and a piston driven by the alternate heating and cooling of a single working mode. We evaluate the extractable work in terms of ergotropy, the kinetic energy associated to net directed rotation, as well as the intrinsic work based on the exerted torque under autonomous operation, and we compare them to the energy output for the case of an external dissipative load and for externally driven engine cycles. Our results connect work definitions from both physical and information-theoretical perspectives. In particular, we find that apart from signatures of angular momentum quantization, the ergotropy is consistent with the intuitive notion of work in the form of net directed motion. It also agrees with the energy output to an external load or agent under optimal conditions. This sets forth a consistent thermodynamical description of rotating quantum motors, flywheels, and clocks.