Non-Thermal Phase Transitions after Inflation

TL;DR

This paper explores how non-thermal quantum fluctuations during early universe reheating can induce unique phase transitions, potentially creating topological defects and triggering secondary inflation, differing from traditional thermal transition models.

Contribution

It introduces a new class of cosmological phase transitions driven by non-thermal quantum fluctuations during reheating after inflation.

Findings

Quantum fluctuations are significantly larger than in thermal equilibrium.

These fluctuations can cause novel phase transitions and defect production.

Secondary inflation may follow reheating due to these transitions.

Abstract

At the first stage of reheating after inflation, parametric resonance may rapidly transfer most of the energy of an inflaton field $\phi$ to the energy of other bosons. We show that quantum fluctuations of scalar and vector fields produced at this stage are much greater than they would be in a state of thermal equilibrium. This leads to cosmological phase transitions of a new type, which may result in a copious production of topological defects and in a secondary stage of inflation after reheating.