Thermodynamics of Information

Abstract

As early as 1867, two years after the introduction of the concept of entropy by Clausius, Maxwell showed that the limitations imposed by the second law of thermodynamics depend on the information that one possesses about the state of a physical system. A "very observant and neat-fingered being", later on named Maxwell demon by Kelvin, could arrange the molecules of a gas and induce a temperature or pressure gradient without performing work, in apparent contradiction to the second law. One century later, Landauer claimed that "information is physical", and showed that certain processes involving information, like overwriting a memory, need work to be completed and are unavoidably accompanied by heat dissipation. Thermodynamics of information analyzes this bidirectional influence between thermodynamics and information processing. The seminal ideas that Landauer and Bennett devised in the 1970s have been recently reformulated in a more precise and general way by realizing that informational states are out of equilibrium and applying new tools from non-equilibrium statistical mechanics.