Even the photon propagator must break de Sitter symmetry

0572395 - FZÚ 2024 RIV NL eng J - Journal Article
Glavan, Dražen - Prokopec, T.
Even the photon propagator must break de Sitter symmetry.
Physics Letters. B. Roč. 841, June (2023), č. článku 137928. ISSN 0370-2693. E-ISSN 1873-2445
R&D Projects: GA ČR(CZ) GA20-28525S
Institutional support: RVO:68378271
Keywords : de Sitter space * early universe particle physics * gauge symmetry * non- equilibrium field theory
OECD category: Particles and field physics
Impact factor: 4.3, year: 2022
Method of publishing: Open access

The propagator for the massless vector field in de Sitter space cannot maintain de Sitter invariance in the general covariant gauge, except in the exactly transverse limit. This is due to a previously overlooked Ward-Takahashi identity that the propagator must satisfy. We construct the propagator that satisfies all the necessary conditions, and that preserves cosmological symmetries and dilation, but breaks spatial special conformal transformations. Our propagator vanishes in the infrared, contrary to previously reported de Sitter invariant results, which is relevant for loop computations.
Permanent Link: https://hdl.handle.net/11104/0348517