Physics

Gravitation

Spacetime

Non-Gaussianity

De Sitter universe

Cosmic microwave background

Slow roll

Cosmological perturbation theory

Mathematics

Mathematical physics

Eternal inflation

Particle physics

Scalar field

Bispectrum

Statistics

Graviton

Unitarity

Spectral density

Inflaton

Inflation (cosmology)

De Sitter space

Geometry

Theoretical physics

Quantum mechanics

Anisotropy

Homogeneous space

Observable

Scalar (mathematics)

Classical mechanics

Universe

Journal of Cosmology and Astroparticle Physics

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.

Building a boostless bootstrap for the bispectrum