Cutting cosmological correlators
File(s)Goodhew_2021_J._Cosmol._Astropart._Phys._2021_003.pdf (982.74 KB)
Published version
Author(s)
Goodhew, H
Jazayeri, S
Lee, MHG
Pajer, E
Type
Journal Article
Abstract
The initial conditions of our universe appear to us in the form of a classical probability distribution that we probe with cosmological observations. In the current leading paradigm, this probability distribution arises from a quantum mechanical wavefunction of the universe. Here we ask what the imprint of quantum mechanics is on the late time observables. We show that the requirement of unitary time evolution, colloquially the conservation of probabilities, fixes the analytic structure of the wavefunction and of all the cosmological correlators it encodes. In particular, we derive in perturbation theory an infinite set of single-cut rules that generalize the Cosmological Optical Theorem and relate a certain discontinuity of any tree-level n-point function to that of lower-point functions. Our rules are closely related to, but distinct from the recently derived Cosmological Cutting Rules. They follow from the choice of the Bunch-Davies vacuum and a simple property of the (bulk-to-bulk) propagator and are astoundingly general: we prove that they are valid for fields with a linear dispersion relation and any mass, any integer spin and arbitrary local interactions with any number of derivatives. They also apply to general FLRW spacetimes admitting a Bunch-Davies vacuum, including de Sitter, slow-roll inflation, power-law cosmologies and even resonant oscillations in axion monodromy. We verify the single-cut rules in a number of non-trivial examples, including four massless scalars exchanging a massive scalar, as relevant for cosmological collider physics, four gravitons exchanging a graviton, and a scalar five-point function.
Date Issued
2021-08
Online Publication Date
2024-06-25T10:57:38Z
Date Acceptance
2021-06-27
ISSN
1475-7516
Publisher
IOP Publishing
Journal / Book Title
Journal of Cosmology and Astroparticle Physics
Volume
2021
Issue
08
Copyright Statement
© 2021 The Author(s) Published by IOP Publishing Ltd on behalf of Sissa Medialab. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
License URI
Identifier
http://dx.doi.org/10.1088/1475-7516/2021/08/003
Publication Status
Published
Article Number
003
Date Publish Online
2021-08-02