Holography and black holes in asymptotically flat FLRW

Abstract

In this paper, we extend the treatment of asymptotically decelerating spatially flat FLRW spacetimes initiated in [1]. We show that a certain class of those metrics is ruled by the asymptotic algebra $\mathfrak{bm}{\mathfrak{s}}_s$, which belongs to a one-parameter family of deformations of $\mathfrak{bms}$. Furthermore, we enlarge our ansatz to include $\text{Diff}(S^2)$ transformations whose asymptotic algebra $\mathfrak{gbm}{\mathfrak{s}}_s$ is a one parameter deformation of $\mathfrak{gbms}$. Therefore, the holographic algebras $\mathfrak{bm}{\mathfrak{s}}_s$ and $\mathfrak{gbm}{\mathfrak{s}}_s$ in FLRW can be related to their flat counterparts through a cosmological holographic flow. Finally, we introduce a logarithmic ansatz in order to account for cosmological black holes, which does not generally satisfy the peeling property but preserves the asymptotic algebra.

20+6 pages, matches the published version