Non-Gaussianity in String Cosmology: A Case Study

TL;DR

This paper investigates non-Gaussianity in string-inspired multi-field inflation models using the δN formalism, providing analytical and numerical insights into non-Gaussian effects and the curvaton scenario in the large volume limit.

Contribution

It offers a detailed analysis of non-Gaussianity in multi-field string inflation models, including conditions for the curvaton scenario and calculations of non-Gaussianity beyond slow-roll.

Findings

Derived conditions for the existence of the curvaton.

Calculated non-Gaussianity generated by curvaton decay.

Extended analysis beyond slow-roll regime.

Abstract

We study non-gaussianity effects, using the $\delta N$ formalism, in a multi-field inflationary model consisting of K\"ahler moduli derived from type IIB string compactification in the large volume limit. The analytical work in this paper mostly follows the separable potential method developed by Vernizzi and Wands. The numerical analysis is then used in computing non-gaussianity beyond slow-roll regime. The possibility of the curvaton scenario is also discussed. We give the condition for the existence of the curvaton and calculate the non-guassianity generated by the curvaton decay in the large volume limit.