Building a boostless bootstrap for the bispectrum

By E. Pajer. Journal of Cosmology and Astroparticle Physics, 2020

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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.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/db41a3908c089692ac0f169efcbb010b346c2070

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Citations in the corpus

The Cosmological Optical Theorem (2020, methodology): “A more detailed discussion can be found in [31], where a large number of bispectra containing scalar and tensor perturbations have been derived from a set of “bootstrap rules”, which do not rely on de Sitter boosts.”