Memory tests uphold the second law of thermodynamics
Physicists have now probed the memory of Maxwell’s demon, a devious, hypothetical beast. By peeking at information retained by a laboratory version of the creature, scientists confirmed the role of information in saving the second law of thermodynamics from the onslaught of a tiny, superpowerful being intent on wreaking havoc.
In work reported online July 3 in the Proceedings of the National Academy of Sciences, a team of researchers created a quantum version of Maxwell’s demon in the lab and measured both the information stored in its memory and the energy it extracted from a system. The results directly illustrate that information plays a key role in the demon’s attempts to distill energy.
Since 1867, when the demon was proposed by physicist James Clerk Maxwell, scientists wondered whether such a creature could violate the second law, a sacred tenet of physics. It