We propose a quantum analog of the internal combustion engine used in most cars. Specifically, we study how to implement the Otto-type quantum heat engine (QHE) with the assistance of a Maxwell's demon. Three steps are required: thermalization, quantum measurement, and quantum feedback controlled by the Maxwell demon. We derive the positive-work condition of this composite QHE. Our QHE can be constructed using superconducting quantum circuits. We explicitly demonstrate the essential role of the demon in this macroscopic QHE.
@article{arxiv.quant-ph/0512063,
title = {Quantum Heat Engines Using Superconducting Quantum Circuits},
author = {H. T. Quan and Y. D. Wang and Yu-xi Liu and C. P. Sun and Franco Nori},
journal= {arXiv preprint arXiv:quant-ph/0512063},
year = {2009}
}