Integral representation of the Feynman propagators of the Dirac fermions on the de Sitter expanding universe

TL;DR

This paper derives a new integral representation for the Feynman propagators of Dirac fermions in de Sitter spacetime, facilitating calculations in quantum field theory on this curved background.

Contribution

It introduces a novel integral form of the Feynman propagators for Dirac fields in de Sitter space, aiding the development of quantum electrodynamics in curved spacetime.

Findings

New integral representation of propagators

Applicable to massive and massless Dirac fields

Enables derivation of Feynman rules in de Sitter QED

Abstract

The propagators of the Dirac fermions on the expanding portion of the (1+3)-dimensional de Sitter spacetime are considered as mode sums in momentum representation with a fixed vacuum of Bunch-Davies type. The principal result reported here is a new integral representation of the Feynman propagators of the massive and left-handed massless Dirac fields which can be used for deriving the Feynman rules of the de Sitter QED in Coulomb gauge or of an extended QFT.