Decoherence of Vacuum Fluctuations in Cosmology

TL;DR

This paper investigates how vacuum fluctuations decohere in cosmological models, revealing that their role in generating classical density perturbations depends on field masses and couplings, with implications for inflationary scenarios.

Contribution

It introduces a new mechanism for decoherence of massive fields and analyzes conditions for density perturbation production in different inflationary models.

Findings

Decoherence of vacuum fluctuations depends on mass and conformal coupling.

Production of adiabatic density perturbations may be suppressed in power-law inflation with p < 3.

A new decoherence mechanism for massive fields in cosmology is identified.

Abstract

A calculation of the one-mode occupation numbers for vacuum fluctuations of massive fields in De Sitter space shows that their use for the generation of classical density perturbations in inflationary cosmology very much depends on their masses and conformal couplings. A new mechanism for the decoherence of relatively massive fields has been identified. A similar analysis of the power law inflation shows that production of adiabatic density perturbations may not take place in models with power p < 3.