Quantum Afterburner: Improving the Efficiency of an Ideal Heat Engine

By using a laser and maser in tandem, it is possible to obtain laser action in the hot exhaust gases of a heat engine. Such a "quantum afterburner" involves the internal quantum states of the working molecules as well as the techniques of cavity quantum electrodynamics and is therefore in the domain of quantum thermodynamics. It is shown that Otto cycle engine performance can be improved beyond that of the "ideal" Otto heat engine. Furthermore, the present work demonstrates a new kind of lasing without initial inversion.