HEP Theory Journal Club

Static sphere observers and geodesics in Schwarzschild-de Sitter spacetime

Mir Mehedi Faruk

McGill

We will study null radial geodesics in Schwarzschild-de Sitter spacetime connecting two conjugate static sphere observers, i.e. free-falling observers at a fixed radius in between the two horizons (based on arXiv:2312.06878). We explicitly determine the changes in the causal structure with respect to these natural observers as a result of the inward bending of the black hole singularity, as well as the outward bending of asymptotic infinity. Notably, the inward and outward bending changes as a function of the black hole mass, first increasing towards a maximum and then decreasing to vanish in the extreme Nariai limit.