Even the photon propagator must break de Sitter symmetry

Research output: Contribution to journalArticleAcademicpeer-review


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. (c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons .org /licenses /by /4 .0/). Funded by SCOAP3.
Original languageEnglish
Article number137928
Number of pages5
JournalPhysics Letters B
Early online dateApr 2023
Publication statusPublished - 10 Jun 2023


  • Massless


Dive into the research topics of 'Even the photon propagator must break de Sitter symmetry'. Together they form a unique fingerprint.

Cite this