General dissipation coefficient in low-temperature warm inflation

TL;DR

This paper calculates the dissipation coefficient in supersymmetric warm inflation models, showing that on-shell decay contributions can dominate despite Boltzmann suppression, thus expanding the potential for warm inflation scenarios.

Contribution

It provides a detailed numerical computation of the dissipation coefficient in supersymmetric models, especially below the heavy mass threshold, highlighting the significance of on-shell decay contributions.

Findings

On-shell decay contributions can dominate the dissipation coefficient.

The dissipation coefficient depends on light field multiplicities and coupling regimes.

Results suggest new possibilities for realizing warm inflation in supersymmetric theories.

Abstract

In generic particle physics models, the inflaton field is coupled to other bosonic and fermionic fields that acquire large masses during inflation and may decay into light degrees of freedom. This leads to dissipative effects that modify the inflationary dynamics and may generate a nearly-thermal radiation bath, such that inflation occurs in a warm rather than supercooled environment. In this work, we perform a numerical computation and obtain expressions for the associated dissipation coefficient in supersymmetric models, focusing on the regime where the radiation temperature is below the heavy mass threshold. The dissipation coefficient receives contributions from the decay of both on-shell and off-shell degrees of freedom, which are dominant for small and large couplings, respectively, taking into account the light field multiplicities. In particular, we find that the contribution from on-shell decays, although Boltzmann-suppressed, can be much larger than that of virtual modes, which is bounded by the validity of a perturbative analysis. This result opens up new possibilities for realizations of warm inflation in supersymmetric field theories.