VON NEUMANN AND SHANNON-WEHRL ENTROPY FOR SQUEEZED STATES AND COSMOLOGICAL PARTICLE PRODUCTION

TL;DR

This paper demonstrates that Wehrl entropy applied to two-mode squeezed states aligns with other entropy measures in describing cosmological particle production, interpreting entropy growth as decoherence from initial condition amplification.

Contribution

It introduces a Wehrl entropy approach to analyze entropy in squeezed states during cosmological particle production, linking it to decoherence and effective coarse graining.

Findings

Wehrl entropy agrees with previous entropy definitions in this context.

Entropy growth interpreted as amplification of initial condition uncertainty.

Effective decoherence arises from squeezing-induced amplification.

Abstract

We show that the effective coarse graining of a two-mode squeezed density matrix, implicit in the Wehrl approaches to a semiclassical phase-space distribution, leads to results in agreement with previous different definitions of entropy for the process of pair production from the vacuum. We also present, in this context, a possible interpretation of the entropy growth as an amplification (due to the squeezing) of our lack of knowledge about the initial conditions, which gives rise to an effective decoherence of the squeezed density matrix.