Charge separation in Reheating after Cosmological Inflation

TL;DR

This paper investigates the process of charge separation during reheating after cosmological inflation, revealing metastable symmetry breaking and persistent charge overdensities that hinder thermalization in a relativistic scalar field model.

Contribution

It introduces new insights into parametric resonance-driven reheating, highlighting metastable symmetry breaking and non-thermal fixed points in a fully symmetric scalar field model.

Findings

Observation of metastable spontaneous symmetry breaking.

Identification of persistent charge overdensities separated by walls.

Discovery of a non-equilibrium fixed point preventing thermalization.

Abstract

New aspects of parametrically resonant heating of a relativistic scalar O(2)-symmetric self-interacting field are presented. This process is a candidate for reheating at the end of the early-universe epoch of inflation. Although a model with a fully O(2)-symmetric ground state is used, transient, metastable spontaneous symmetry breaking can be observed. This manifests itself in the form of persistent regimes of opposite and, inside these, uniform charge overdensities separated by thin lines and walls similar to topological defects, in two and three spatial dimensions, respectively. The configuration is found to correspond to an attractive non-equilibrium fixed point of the underlying dynamic equations which prevents thermalisation over an extended period of time.