Maxwell’s demon gets scribbling

Published in Chemistry World, 30 Jul 2013

Maxwell’s demon is a famous thought experiment designed to show how, in an isolated system, disorder or ‘entropy’ can decrease in apparent violation of the second law of thermodynamics. Now researchers in the US have put a new twist on the idea, claiming to show theoretically how the second law can remain intact if the demon is allowed to scribble down random information.

In the original thought experiment, proposed by the UK physicist James Clerk Maxwell in 1867, a demon sits between two isolated chambers. By carefully timing the opening of a hatch between the chambers, the demon can let only slower, ‘cold’ particles through to one side, and only faster, ‘hot’ particles through to the other. Without expending energy then, the demon makes the system more ordered, lowering entropy and apparently violating the second law. […]

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