The Cosmological Slavnov-Taylor Identity from BRST Symmetry in Single-Field Inflation

TL;DR

This paper derives the cosmological Slavnov-Taylor identity from BRST symmetry in single-field inflation, linking fundamental symmetries to consistency relations among cosmological correlators.

Contribution

It establishes the ST identity in the cosmological context from BRST symmetry, recovering Maldacena's relations and extending them with next-to-leading corrections.

Findings

Derivation of the cosmological Slavnov-Taylor identity from BRST symmetry.

Recovery of Maldacena's relations for correlators at horizon crossing.

Extension of consistency relations with conformal symmetry corrections.

Abstract

The cosmological Slavnov-Taylor (ST) identity of the Einstein-Hilbert action coupled to a single inflaton field is obtained from the Becchi-Rouet-Stora-Tyutin (BRST) symmetry associated with diffeomorphism invariance in the Arnowitt-Deser-Misner (ADM) formalism. The consistency conditions between the correlators of the scalar and tensor modes in the squeezed limit are then derived from the ST identity, together with the softly broken conformal symmetry. Maldacena's original relations connecting the 2- and 3-point correlators at horizon crossing are recovered, as well as the next-to-leading corrections, controlled by the special conformal transformations.