Asymptotic symmetries and charges in de Sitter space

Abstract

The asymptotic symmetry group (ASG) at future null infinity (I^+) of\nfour-dimensional de Sitter spacetimes is defined and shown to be given by the\ngroup of three-dimensional diffeomorphisms acting on I^+. Finite charges are\nconstructed for each choice of ASG generator together with a two-surface on\nI^+. A conservation equation is derived relating the evolution of the charges\nwith the radiation flux through I^+.\n