Less is more for Maxwell's Demon in quantum heat engines

Over 150 years after the famous Scottish scientist James Clerk Maxwell first introduced the idea, the concept of Maxwell's demon continues to perplex physicists and information scientists. The demon he dreamed up in a thought experiment, which could sort fast and slow particles into separate sides of a container, seemed to violate the second law of thermodynamics. By taking into account the demon's memory, physicists were able to bring the demon in line with the laws of statistical mechanics for classical systems, but the situation grew contentious once again when quantum heat engines were proposed, as thermodynamics physicists and information theorists wrangled over viable explanations. Recent results from physical modeling may bring the different arguments together.