Non-Gaussianity from false vacuum inflation: Old curvaton scenario

TL;DR

This paper derives a novel bispectrum shape from false vacuum inflation, introduces the 'old curvaton' scenario, and discusses its implications for the curvature perturbation's non-Gaussianity and spectral index running.

Contribution

It presents the first calculation of a false vacuum shape bispectrum and proposes the 'old curvaton' scenario with distinctive non-Gaussian features.

Findings

Novel false vacuum bispectrum peaks in equilateral limit

The 'old curvaton' scenario produces a bispectrum shape between local and false vacuum types

Large running of the spectral index observed

Abstract

We calculate the three-point correlation function of the comoving curvature perturbation generated during an inflationary epoch driven by false vacuum energy. We get a novel false vacuum shape bispectrum, which peaks in the equilateral limit. Using this result, we propose a scenario which we call "old curvaton". The shape of the resulting bispectrum lies between the local and the false vacuum shapes. In addition we have a large running of the spectral index.