On Coarse-grained Entropy and Stimulated Emission in Curved Space-Time

TL;DR

This paper investigates entropy generation and particle production in scalar quantum fields within expanding spacetimes, revealing that initial particles can attenuate entropy growth despite enhanced particle creation due to boson statistics.

Contribution

It applies the coarse-grained entropy approach to systems with initial particles, showing attenuation of entropy generation in expanding spacetimes.

Findings

Particle production is amplified by boson statistics.

Entropy generation is reduced when initial particles are present.

The approach extends to systems with non-zero initial entropy.

Abstract

We study the entropy generation and particle production in scalar quantum field theory in expanding spacetimes with many-particle mixed initial states. The recently proposed coarse-grained entropy approach by Brandenberger et. al. is applied to systems which may have a non-zero initial entropy. We find that although the the particle production is amplified as a result of boson statistics, the (coarse-grained) entropy generation is {\em attenuated} when initial particles are present.