Effective Field Theory for Inflation

TL;DR

This paper employs effective field theory methods to analyze generic single-field inflation models, focusing on non-Gaussianities and their shapes in three and four-point correlators, revealing new potential signatures from extrinsic curvature interactions.

Contribution

It extends the effective field theory approach to inflation, highlighting the role of extrinsic curvature interactions in generating distinctive non-Gaussian signatures.

Findings

Extrinsic curvature interactions can produce large non-Gaussianities.

Different inflationary models yield specific shapes of correlators.

The analysis recovers known models and explores new interaction effects.

Abstract

This is a version of the author's Ph.D. thesis. 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 three and four-point correlators which are generated by different classes of single-field inflationary models. Besides the well-known results for the so called P(X,\phi) model and the ghost inflationary theories, which we recover, we point out that extrinsic curvature-generated interactions may give rise to large non-Gaussianities with distinctive features in the form of specific shape-functions (e.g. flat, orthogonal etc..) for the correlators.