The Second Law of Thermodynamics says that entropy in the universe must always increase. It's an immutable law of physics, and it's the reason you can't get free energy or perpetual motion machines. But a group of physicists may have found a way to break this law, at least in some specific circumstances. The researchers, from Argonne National Laboratory, have developed a theoretical model where the Second Law is violated on a molecular level. Their results are published in the journal Science Direct. The basic idea behind the discovery is the H-theorem, which says if you mix a hot thing and a cold thing, the mixture will end up somewhere in the middle. The H-theorem relies on a statistical interpretation