title: Entropy and wigner functions
abstract: The properties of an alternative definition of quantum entropy, based on Wigner functions, are discussed. Such a definition emerges naturally from the Wigner representation of quantum mechanics, and can easily quantify the amount of entanglement of a quantum state. It is shown that smoothing of the Wigner function induces an increase in entropy. This fact is used to derive some simple rules to construct positive-definite probability distributions which are also admissible Wigner functions.
authors.affiliation: Laboratoire de Physique des Milieux Ionises, Universite Henri Poincare, BP239, 54506 Vandoeuvre-les-Nancy, France.
authors.initials: G
authors.lastname: Manfredi
authors.initials: MR
authors.lastname: Feix