Quantum Optomechanical Heat Engine

TLDR

In generic optomechanical systems, cavity–mirror coupling produces polariton normal modes whose character depends on pump detuning and coupling strength. The study theoretically investigates a quantum optomechanical heat engine and exploits differing reservoir temperatures to implement an Otto cycle along a polariton branch. By tuning the pump detuning, the polariton character shifts between phonon‑like and photon‑like, enabling coupling to distinct thermal reservoirs and allowing an Otto cycle to be executed along a chosen polariton branch. The engine can extract work from a finite‑temperature mechanical resonator in the optical regime, and in the microwave regime it can in principle harvest work from blackbody radiation coupled to an ultra‑cold atomic ensemble.

Abstract

We investigate theoretically a quantum optomechanical realization of a heat engine. In a generic optomechanical arrangement the optomechanical coupling between the cavity field and the oscillating end-mirror results in polariton normal mode excitations whose character depends on the pump detuning and the coupling strength. By varying that detuning it is possible to transform their character from phonon-like to photon-like, so that they are predominantly coupled to the thermal reservoir of phonons or photons, respectively. We exploit the fact that the effective temperatures of these two reservoirs are different to produce a Otto cycle along one of the polariton branches. We discuss the basic properties of the system in two different regimes: in the optical domain it is possible to extract work from the thermal energy of a mechanical resonator at finite temperature, while in the microwave range one can in principle exploit the cycle to extract work from the blackbody radiation background coupled to an ultra-cold atomic ensemble.