Large non-Gaussianities in the Effective Field Theory Approach to Single-Field Inflation: the Bispectrum

TL;DR

This paper uses effective field theory to analyze non-Gaussianities in single-field inflation, focusing on the bispectrum's amplitude and shape, revealing that curvature interactions can produce large, flat-shaped non-Gaussianities.

Contribution

It provides a comprehensive analysis of bispectrum shapes and amplitudes in single-field inflation models, highlighting the role of curvature-related interactions in generating large non-Gaussianities.

Findings

Curvature interactions can produce large non-Gaussianities with flat bispectrum shapes.

Multiple interaction terms independently generate similar flat bispectrum shapes.

The study extends understanding of non-Gaussian features in inflationary models.

Abstract

The methods of effective field theory are used to study generic theories of inflation with a single inflaton field and to perform a general analysis of the associated non-Gaussianities. We investigate the amplitudes and shapes of the various generic three-point correlators, the bispectra, which may be generated by different classes of single-field inflationary models. Besides the well-known results for the DBI-like models and the ghost inflationary theories, we point out that curvature-related interactions may give rise to large non-Gaussianities in the form of bispectra characterized by a flat shape which, quite interestingly, is independently produced by several interaction terms. In a subsequent work, we will perform a similar general analysis for the non-Gaussianities generated by the generic four-point correlator, the trispectrum.