Distinctive signatures of space-time diffeomorphism breaking in EFT of inflation

TL;DR

This paper explores how breaking both time and space diffeomorphisms during inflation affects observable signatures, providing new ways to constrain inflationary models through scalar and tensor mode statistics.

Contribution

It develops an effective field theory framework for inflation with simultaneous breaking of time and space diffeomorphisms, analyzing observational signatures and constraints.

Findings

Enhanced squeezed bispectra amplitude

Distinctive angular dependence in three-point functions

Potential to constrain spatial diffeomorphism breaking

Abstract

The effective field theory of inflation is a powerful tool for obtaining model independent predictions common to large classes of inflationary models. It requires only information about the symmetries broken during the inflationary era, and on the number and nature of fields that drive inflation. In this paper, we consider the case for scenarios that simultaneously break time reparameterization and spatial diffeomorphisms during inflation. We examine how to analyse such systems using an effective field theory approach, and we discuss several observational consequences for the statistics of scalar and tensor modes. For example, examining the three point functions, we show that this symmetry breaking pattern can lead to an enhanced amplitude for the squeezed bispectra, and to a distinctive angular dependence between their three wavevectors. We also discuss how our results indicate prospects for constraining the level of spatial diffeomorphism breaking during inflation.