De Sitter horizons and holography

Abstract

Asymptotically AdS spacetimes have shown to be a powerful tool to probe black hole event horizons in the context of holography. Observers in de Sitter are surrounded by cosmological event horizons. In order to use the tools from holography to describe the cosmological horizon, we need to embed (a patch of) de Sitter into an asymptotically AdS spacetime. I will show how to build these geometries in the context of two-dimensional dilaton-gravity theories. Then I will focus on one particular observable: the length of spacelike geodesics anchored at the boundaries of double-sided geometries. I will show important differences between the black hole and the cosmological horizon case and comment on possible interpretations of this result in terms of the microscopic dual theories.