Identifying Universality in Warm Inflation

TL;DR

This paper applies renormalization group ideas to warm inflation, classifying models into universality classes and analyzing conditions for smooth transition to radiation dominance, extending cold inflation classifications.

Contribution

It introduces a framework using renormalization group flows to categorize warm inflation models into universality classes, bridging cold and warm inflation.

Findings

Warm inflation models can be classified into universality classes.

The approach characterizes conditions for smooth end to inflation.

Universality classes from cold inflation extend to warm inflation.

Abstract

Ideas borrowed from renormalization group are applied to warm inflation to characterize the inflationary epoch in terms of flows away from the de Sitter regime. In this framework different models of inflation fall into universality classes. Furthermore, for warm inflation this approach also helps to characterise when inflation can smoothly end into the radiation dominated regime. Warm inflation has a second functional dependence compared to cold inflation due to dissipation, yet despite this feature, it is shown that the universality classes defined for cold inflation can be consistently extended to warm inflation.