Information measures and classicality in quantum mechanics

Abstract

We study information measures in quantu mechanics, with particular emphasis on providing a quantification of the notions of classicality and predictability. Our primary tool is the Shannon - Wehrl entropy I. We give a precise criterion for phase space classicality and argue that in view of this a) I provides a measure of the degree of deviation from classicality for closed system b) I - S (S the von Neumann entropy) plays the same role in open systems We examine particular examples in non-relativistic quantum mechanics. Finally, (this being one of our main motivations) we comment on field classicalisation on early universe cosmology.

35 pages, LATEX

References in corpus (2)

• Quantum-to-classical transition for fluctuations in the early Universe
• Classicality via hydrodynamics in quantum field theory

Cited by in corpus (7)

• Classical Dynamics of the Quantum Harmonic Chain
• Linear Positivity and Virtual Probability
• Quantum correlation functions and the classical limit
• Tomographic Representation of Minisuperspace Quantum Cosmology and Noether Symmetries
• Time dependence of joint entropy of oscillating quantum systems
• Classicality via hydrodynamics in quantum field theory
• A Measure of Classicality