FLRW embeddings in , differential geometry and conformal photon propagator
Phys. Rev. D 113, 065018 – Published 24 March, 2026
DOI: https://doi.org/10.1103/x3g4-b6s9
Abstract
This paper introduces differential-geometric methods to study -dimensional locally conformally flat spaces as submanifolds in . We derive explicit formulas relating intrinsic and ambient differential-geometric objects, including curvature tensors, the codifferential, and Laplacian operators. We apply this approach to Friedmann-Lemaître-Robertson-Walker (FLRW) spaces using newfound embedding formulas, obtaining new and simplified expressions for the photon propagator in four dimensions.