Curvaton model completed

TL;DR

This paper revisits the curvaton model in inflationary cosmology, incorporating decay effects, potential corrections, and thermal bath influences, significantly altering the model's dynamics and predictions.

Contribution

It provides the first consistent account of curvaton decay in the simplest quadratic potential, revealing important corrections to the potential and dynamics.

Findings

Logarithmic correction to the curvaton potential

Thermal bath effects modify curvaton dynamics

Recalculation of model predictions is necessary

Abstract

In an inflationary cosmology, the observed primoridal density perturbation could come from the quantum fluctuations of another light 'curvaton' field, rather than the inflaton. In this case, it is essential that the curvaton decays, converting its perturbation to an adiabatic perturbation. For the first time, we consistently account for this decay in the simplest curvaton model V(\sigma) = (m^2\sigma^2)/2 and point out that it gives rise to an important logarithmic correction to the potential. Moreover, the potential will also receive a correction from the thermal bath. As a consequence, the dynamics of the curvaton are substantially altered compared to the original model in the majority of the parameter space. It will therefore be necessary to re-calculate all the predictions of the original model.