A Consistency Relation for Power Law Inflation in DBI models

TL;DR

This paper derives a consistency relation linking non-gaussianity parameters with scalar and tensor indices in power law inflation models within string theory, applicable across various throat geometries and potential configurations.

Contribution

It introduces a new consistency relation connecting non-gaussianity running with spectral indices in DBI power law inflation models.

Findings

The relation holds for any throat geometry supporting power law inflation.

It applies regardless of the non-gaussianity level.

Provides a tool for testing inflation models against observations.

Abstract

Brane inflation in string theory leads to a new realization of power law inflation which can give rise to significant non-gaussianity. This can happen for any throat geometry if the scalar potential is appropriate. This note presents a consistency relation connecting the running of the nonlinearity parameter characterizing the non-gaussianity and the scalar and tensor indices. The relationship is valid assuming that the throat geometry and scalar potential support power law inflation, regardless of the level of non-gaussianity.