Towards a unification of physics and information theory

I. Devetak, A. E. Staples

Published 2001-12-26, updated 2002-04-03Version 5

A common framework for quantum mechanics, thermodynamics and information theory is presented. It is accomplished by reinterpreting the mathematical formalism of Everett's many-worlds theory of quantum mechanics and augmenting it to include preparation according to a given ensemble. The notion of \emph{directed entanglement} is introduced through which both classical and quantum communication over quantum channels are viewed as entanglement transfer. This point is illustrated by proving the Holevo bound and quantum data processing inequality relying exclusively on the properties of directed entanglement. Within the model, quantum thermodynamic entropy is also related to directed entanglement, and a simple proof of the second law of thermodynamics is given.