A photonic quantum engine driven by superradiance

TL;DR

This paper demonstrates the first experimental realization of a photonic quantum engine driven by superradiance, achieving high efficiency and power enhancement using quantum coherence in a single heat reservoir.

Contribution

It provides the first proof-of-principle experimental demonstration of a superradiance-driven quantum engine utilizing a single heat reservoir with quantum coherence.

Findings

Engine temperature increased 40-fold due to superradiance.

Engine efficiency approached unity.

Output power scaled quadratically with atomic injection rate.

Abstract

Performance of nano- and micro-scale heat engines can be improved with a help from quantum mechanical phenomena. Recently, heat reservoirs with quantum coherence have been proposed to enhance engine performance beyond the Carnot limit even with a single reservoir. However, no physical realizations have been achieved so far. Here, we report the first proof-of-principle experimental demonstration of a photonic quantum engine driven by superradiance employing a single heat reservoir composed of atoms and photonic vacuum. Reservoir atoms prepared in a quantum coherent superposition state underwent superradiance while traversing the cavity. This led to about 40-fold increase of the effective engine temperature, resulting in a near-unity engine efficiency. Moreover, the observed engine output power grew quadratically with respect to the atomic injection rate. Our work can be utilized in quantum mechanical heat transfer as well as in boosting engine powers, opening a pathway to development of photomechanical devices that run on quantum coherence embedded in heat baths.