2026/07/27 by Manizheh Botshekananfard, Elif Büşra Güraksın, Vasileios A. Letsios +1
#hep-th #gr-qc
We study the free Maxwell field on the planar patch of four-dimensional de Sitter spacetime (dS4). We review its bulk canonical quantization in the Bunch-Davies vacuum, and we give a representation-theoretic viewpoint by studying the transformation properties of single-particle states under infinitesimal dS transformations. By taking the late-time limit, we identify two late-time operators with scaling dimensions Δ=1 (leading) and Δ=2 (subleading). We introduce CFT-inspired inner products invariant under the dS group (SO(4,1)) for states created by late-time operators acting on the Bunch-Davies vacuum. We explain how the unitary discrete series representations of SO(4,1) associated with the photon are furnished by both operators, in contrast with the Maxwell field on AdS where the Δ=1 operator corresponds to a non-normalizable mode. We also explain how the corresponding discrete series representations of SO(4,1) split into a direct sum of representations corresponding to two helicities +1 and -1. This is achieved by taking advantage of the dS invariance of the self-dual and anti-self-dual sectors of the photon field strength. In our outlook, we draw inspiration from a recent proposal for the microscopic description of dS4 higher-spin gravity where conformal gauge fields in 3 dimensions play a central role, and we investigate a possible connection of the Δ=1 late-time operator with a conformal spin-1 gauge field in 3 dimensions.