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Building a boostless bootstrap for the bispectrum

Accepted version
Peer-reviewed

Type

Article

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Authors

Abstract

The observation of primordial correlators by cosmological surveys is a very promising avenue to probe high energies and the perturbative regime of quantum gravity. Hence, it is imperative that we understand how these observables are shaped by the pillars of fundamental physics, namely unitarity, locality and symmetries. To this end, we study the three-point correlators of gravitons and scalar curvature perturbations around a quasi de Sitter spacetime. We identify a set of Bootstrap Rules that fully fix the form of these correlators in the asymptotic future, i.e. at the boundary, and make no reference to bulk time evolution. Importantly, our Boostless Bootstrap accounts for the ubiquitous (spontaneous) breaking of de Sitter boosts caused by any inflationary background. We show how all bispectra involving gravitons in single-clock, canonical inflation can be easily derived in this approach. We also derive for the first time the scalar bispectrum in the Effective Field Theory of inflation to any order in derivatives. In many cases, our derivation is computationally simpler than the corresponding explicit calculation, and makes particularly transparent the implications of locality, the choice of vacuum, and the underlying symmetries.

Description

Keywords

non-gaussianity, primordial gravitational waves (theory), cosmological perturbation theory, inflation

Journal Title

Journal of Cosmology and Astroparticle Physics

Conference Name

Journal ISSN

1475-7516
1475-7516

Volume Title

2021

Publisher

IOP Publishing

Rights

All rights reserved
Sponsorship
Science and Technology Facilities Council (ST/P000673/1)
STFC (ST/T00049X/1)
EPSRC (EP/V048422/1)