DBI-Curvaton

TL;DR

This paper investigates a DBI-curvaton model, revealing enhanced curvature perturbations and larger non-Gaussianity compared to traditional models, with implications for lower inflationary scales and observational signatures.

Contribution

It introduces a DBI-curvaton framework, analyzing its perturbation spectrum and non-Gaussianity, expanding brane-cosmology applications in inflationary theory.

Findings

Enhanced curvature perturbation amplitude at low sound speed

Non-Gaussianity level about 10 times larger than usual curvaton

Potential for lower inflationary scale in DBI-curvaton model

Abstract

In this paper, we study a curvaton model described by a Dirac-Born-Infeld-like action. We calculate the spectrum of curvature perturbation induced by DBI-curvaton and estimate its non-Gaussianity. We find that in the limit of low sound speed the amplitude of curvature perturbation is enhanced more than that in DBI inflation. This result also means that the inflationary scale with DBI-curvaton may be lower than that in usual curvaton model. In addition, we also find that the local non-Gaussianity level in DBI-curvaton is generally about 10 times larger than that in usual curvaton model, which is interesting for current observations. This work in some sense explores a new application of brane-cosmology in inflation.