Effective Field Theory for Inflation

TL;DR

This paper applies effective field theory techniques to inflation, analyzing scalar and tensor mode corrections, including parity-violating effects, and extends to non-generic models like ghost inflation.

Contribution

It introduces a systematic EFT approach to inflation, detailing corrections to scalar and tensor modes, and explores parity violation and non-generic models.

Findings

Scalar mode corrections are of the $k$-inflation type.

Tensor mode corrections include parity-violating terms.

Methods are extended to ghost inflation models.

Abstract

The methods of effective field theory are used to study generic theories of inflation with a single inflaton field. For scalar modes, the leading corrections to the ${\cal R}$ correlation function are found to be purely of the $k$-inflation type. For tensor modes the leading corrections to the correlation function arise from terms in the action that are quadratic in the curvature, including a parity-violating term that makes the propagation of these modes depend on their helicity. These methods are also briefly applied to non-generic theories of inflation with an extra shift symmetry, as in so-called ghost inflation.