Effective Field Theory for Inflation

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.