Constraining parameters of effective field theory of inflation from Planck data

TL;DR

This paper uses Planck data to constrain parameters of the effective field theory of inflation by analyzing non-Gaussianities in the cosmic microwave background, focusing on the Goldstone action and curvature perturbations.

Contribution

It provides a novel method to derive constraints on inflationary parameters from Planck data using the effective field theory framework and Goldstone boson interactions.

Findings

Constraints on $f_{NL}^{ ext{dot}\pi^3}$ and $f_{NL}^{ ext{dot}\pi( abla \pi)^2}$

Estimated the speed of sound $c_s$ during inflation

Linked non-Gaussianity parameters to inflationary physics

Abstract

The Cosmic Microwave Background can provide information regarding physics of the very early universe, more specifically, of the matter-radiation distribution of the inflationary era. Starting from the effective field theory of inflation, we use the Goldstone action to calculate the three point correlation function for the Goldstone field, whose results can be directly applied to the field describing the curvature perturbations around a de Sitter solution for the inflationary era. We then use the data from the recent Planck mission for the parameters $f_{NL}^{equil}$ and $f_{NL}^{orthog}$ which parametrize the size and shape of non-Gaussianities generated in single field models of inflation. Using these known values, we calculate the parameters relevant to our analysis, $f_{NL}^{\dot{\pi}^3}$, $f_{NL}^{\dot{\pi}(\partial _i \pi)^2}$ and the speed of sound $c_s$ which parametrize the non-Gaussianities arising from two different kinds of generalized interactions of the scalar field in question.