Density perturbations from curvatons revisited

We investigate density perturbations sourced by a curvaton with a generic energy potential. The key feature of a curvaton potential which deviates from a quadratic is that the curvaton experiences a non-uniform onset of its oscillation. This sources additional contributions to the resulting density perturbations, and we especially find that curvaton potentials that are flatter compared to a quadratic lead to enhancement of the linear and second-order density perturbations, while steepened potentials can generate strongly scale-dependent non-Gaussianity. As such examples, we study pseudo-Nambu- Goldstone curvatons and self-interacting curvatons. Our analyses are analytic, and thus provide a systematic framework for studying curvatons in general. The discussion in this paper are based on [1, 2]. © Published under licence by IOP Publishing Ltd.