A comparative analysis of dissipation coefficients in warm inflation

TL;DR

This paper compares different dissipation coefficient models in warm inflation using recent CMB data, finding some models competitive with Starobinsky inflation and providing improved constraints.

Contribution

It constrains various dissipation coefficient parameterizations in warm inflation with updated observational data and compares their viability.

Findings

Some warm inflation models are competitive with Starobinsky inflation.

Updated constraints significantly improve over previous results.

Bayesian analysis favors certain dissipation models based on observational data.

Abstract

In the warm inflation scenario, the early cosmic acceleration is driven by the inflaton coupled to thermal fields, decaying into radiation and leaving a hot universe populated by relativistic particles after the end of inflation. The interaction is usually modeled by a dissipation coefficient $\Upsilon$ that contains the microphysics of the model. In this work, we adopt a well-motivated potential $V(\phi)=\frac{\lambda}{4}\phi^4$ and constrain a variety of $\Upsilon$ parameterizations by using updated Cosmic Microwave Background data from the \textit{Planck} and \textit{BICEP/Keck Array} collaborations. We also use a Bayesian statistical criterion to compare the observational viability of these models. Our results show a significant improvement in the constraints over past results reported in the literature and also that some of these warm inflation models can be competitive compared to Starobinsky inflation.