Rotating a Curvaton Brane in a Warped Throat

TL;DR

This paper investigates a curvaton model involving a rotating anti-D3-brane in a warped throat, analyzing its perturbation spectrum and non-Gaussianities, with implications for early universe cosmology.

Contribution

It introduces a novel DBI-curvaton mechanism with relativistic brane rotation, providing detailed spectral and non-Gaussianity predictions and exploring observational constraints.

Findings

Primordial power spectrum is nearly scale-invariant.

Non-Gaussianity of local type is sizable.

Equilateral non-Gaussianity is large and negative.

Abstract

In this paper we study a curvaton model obtained by considering a probe anti-D3-brane with angular motion at the bottom of a KS throat with approximate isometries. We calculate the spectrum of curvature perturbations and the non-Gaussianities of this model. Specifically, we consider the limit of relativistic rotation of the curvaton brane which leads to a small sound speed, and thus it can be viewed as an implementation of the DBI-curvaton mechanism. We find that the primordial power spectrum is nearly scale-invariant while the non-Gaussianity of local type is sizable and that of equilateral type is usually large and negative. Moreover, we study both the theoretical and observational constraints on this model, and find that there exists a sizable allowed region for the phase space of this model.