An optical cavity like this could be used in a quantum engine
Max Planck Institute of Quantum Optics
A single atom inside of a reflective cavity could be enough to drive a piston in a tiny, quantum version of an engine.
The essential feature of any engine is that it converts heat into work, which can then set mechanical parts into motion. For internal combustion engines, burning gas makes it expand and push on pistons, which eventually results in car wheels or turbine blades moving. Álvaro Tejero at the University of Granada in Spain and his…
