Large-distance behavior of the massless vector two-point function in de Sitter spacetime

摘要

We study the long-distance behavior of the massless vector propagator in n-dimensional de Sitter spacetime, where n ≥ 4. Specifically, we consider the massless limit of the vector propagator in the Stueckelberg theory, which is an extension of Proca theory, with an additional gauge-fixing term. We work to leading order in the de Sitter-invariant distance Z to show that, in the large Z limit, this propagator tends to a gauge-dependent constant, where the gauge worked in is described by the Stueckelberg parameter ξ. In the Landau gauge, where ξ = 0, this constant is found to be 0. This result is in agreement with the four-dimensional case discussed by Youssef.