The Inflationary Wavefunction from Analyticity and Factorization
Abstract
We study the analytic properties of treelevel wavefunction coefficients in quaside Sitter space. We focus on theories which spontaneously break dS boost symmetries and can produce significant nonGaussianities. The corresponding inflationary correlators are (approximately) scale invariant, but are not invariant under the full conformal group. We derive cutting rules and dispersion formulas for the latetime wavefunction coefficients by using factorization and analyticity properties of the dS bulktobulk propagator. This gives a unitarity method which is valid at treelevel for general $n$point functions and for fields of arbitrary mass. Using the cutting rules and dispersion formulas, we are able to compute $n$point functions by gluing together lowerpoint functions. As an application, we study general fourpoint, scalar exchange diagrams in the EFT of inflation. We show that exchange diagrams constructed from boostbreaking interactions can be written as a finite sum over residues. Finally, we explain how the dS identities used in this work are related by analytic continuation to analogous identities in Antide Sitter space.
 Publication:

arXiv eprints
 Pub Date:
 July 2021
 arXiv:
 arXiv:2107.10266
 Bibcode:
 2021arXiv210710266M
 Keywords:

 High Energy Physics  Theory;
 Astrophysics  Cosmology and Nongalactic Astrophysics;
 General Relativity and Quantum Cosmology;
 High Energy Physics  Phenomenology
 EPrint:
 29 pages + appendices, v2: Typos corrected and references added