Edinburgh Research Explorer

Fluctuation-dissipation dynamics of cosmological scalar fields

Research output: Contribution to journalArticle

Related Edinburgh Organisations

Open Access permissions

Open

Original languageEnglish
Article number083540
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Volume91
Issue number8
DOIs
StatePublished - 29 Apr 2015

Abstract

We show that dissipative effects have a significant impact on the evolution of cosmological scalar fields, leading to friction, entropy production and field fluctuations. We explicitly compute the dissipation coefficient for different scalar fields within the standard model and some of its most widely considered extensions, in different parametric regimes. We describe the generic consequences of fluctuation-dissipation dynamics in the postinflationary universe, focusing in particular on friction and particle production, and analyze in detail two important effects. First, we show that dissipative friction delays the process of spontaneous symmetry breaking and may even damp the motion of a Higgs field sufficiently to induce a late period of warm inflation. Along with dissipative entropy production, this may parametrically dilute the abundance of dangerous thermal relics. Second, we show that dissipation can generate the observed baryon asymmetry without symmetry restoration, and we develop in detail a model of dissipative leptogenesis. We further show that this generically leads to characteristic baryon isocurvature perturbations that can be tested with cosmic microwave background observations. This work provides a fundamental framework to go beyond the leading thermal equilibrium semiclassical approximation in addressing fundamental problems in modern cosmology.

Download statistics

No data available

ID: 21303165