Extended Effective Field Theory of Inflation

TL;DR

This paper extends the effective field theory of single field inflation by including higher dimensional operators, analyzing their impact on scalar perturbations and CMB observables, while tensor modes remain unaffected.

Contribution

It introduces a framework incorporating operators of mass dimension 3 and 4, leading to new corrections in the dispersion relation of inflationary perturbations.

Findings

Higher dimensional operators modify the dispersion relation of scalar perturbations.

These operators affect the speed of sound and amplitude of the power spectrum.

Tensor perturbations are unaffected by the extended operators.

Abstract

We present a general framework where the effective field theory of single field inflation is extended by the inclusion of operators with mass dimension 3 and 4 in the unitary gauge. These higher dimensional operators introduce quartic and sextic corrections to the dispersion relation. We study the regime of validity of this extended effective field theory of inflation and the effect of these higher dimensional operators on CMB observables associated with scalar perturbations, such as the speed of sound, the amplitude of the power spectrum and the tensor-to-scalar ratio. Tensor perturbations remain instead, unaltered.