Holography and black holes in asymptotically flat FLRW spacetimes

In this paper, we extend the treatment of asymptotically decelerating spatially flat Friedmann-Lemaître-Robertson-Walker (FLRW) spacetimes initiated in [M. E. Rojo and T. Heckelbacher, Phys. Rev. D 103, 064009 (2021)., 10.1103/PhysRevD.103.064009]. We show that a certain class of those metrics is ruled by the asymptotic algebra b m s_s, which belongs to a one-parameter family of deformations of b m s . Furthermore, we enlarge our ansatz to include Diff(S²) transformations whose asymptotic algebra g b m s_s is a one-parameter deformation of g b m s . Therefore, the holographic algebras b m s_s and g b m 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.