## Breaking The Law

The Second Law of Thermodynamics states that entropy within an isolated system always increases. This iron-clad law has remained true for a very long time. However, researchers from the U.S. Department of Energy's (DOE) Argonne National Laboratory may have found a way to violate this.

The foundation of this law is in the H-theorem, which states that if you open a door between two rooms, one hot and the other cold, both rooms' temperature would eventually reach equilibrium making them both lukewarm.

While the H-theorem has been observed in a macroscopic level, scientists could not fully grasp its fundamental physical origin. In a study published in *Scientific Reports*, quantum information theory was able to offer a mathematical construct where entropy increases. It predicted that there are certain conditions where entropy might actually decrease in the short term.

"This allowed us to formulate the quantum H-theorem as it related to things that could be physically observed," said Ivan Sadovskyy, a joint appointee with Argonne's Materials Science Division and the Computation Institute and one of the authors on the paper. "It establishes a connection between well-documented quantum physics processes and the theoretical quantum channels that make up quantum information theory."

## Building The Impossible

Their work is not the only one to theorize a violation of this law. In 1867, physicist James Clerk Maxwell designed a thought experiment where a hypothetical being would act as a sort of night club bouncer between the hot and cold room. That being, known as "Maxwell's Demon," would only let in particles of certain speeds. The study could "provide a platform for the practical realization of a quantum Maxwell's demon," says Valerii Vinokur, an Argonne Distinguished Fellow and the other author of the study

Vinokur hopes that this could lead into the creation of seemingly impossible machines like a local quantum perpetual motion machine. Another use he sees would be to apply the principles powering devices remotely. In the example he uses, a refrigerator would be able to be cooled at another location.