Soft theorems for boosts and other time symmetries
Abstract
We derive soft theorems for theories in which time symmetries -- symmetries that involve the transformation of time, an example of which are Lorentz boosts -- are spontaneously broken. The soft theorems involve unequal-time correlation functions with the insertion of a soft Goldstone in the far past. Explicit checks are provided for several examples, including the effective theory of a relativistic superfluid and the effective field theory of inflation. We discuss how in certain cases these unequal-time identities capture information at the level of observables that cannot be seen purely in terms of equal-time correlators of the field alone. We also discuss when it is possible to phrase these soft theorems as identities involving equal-time correlators.
Cite
@article{arxiv.2210.16276,
title = {Soft theorems for boosts and other time symmetries},
author = {Lam Hui and Austin Joyce and Ilia Komissarov and Klaas Parmentier and Luca Santoni and Sam S. C. Wong},
journal= {arXiv preprint arXiv:2210.16276},
year = {2023}
}
Comments
50 pages