de Sitter quantum gravity and information via T\bar T

After briefly reviewing de Sitter models in string theory (including a new
class under development), I will highlight basic structural constraints which enter into its holographic description. For the bulk of the talk I will explain a holographic duality for
patches of (A)dS spacetimes obtained from concrete generalizations of the solvable $T\bar T$ deformation, supported by explicit agreement of the energy spectrum on the two sides along with a growing list of matching information-theoretic quantities. In particular, I will present our recent analysis of subregion dualities, building from new calculations of entanglement entropy which match precisely on both sides of the duality. Along the way I will comment on novel features of the operator algebras in these systems. These results probe the form of nonlocality (consistently with causality) arising in $T\bar T$ deformed theories, and exhibit the phenomenon of redundant encoding of bulk operators (quantum error correction) in the more realistic case of de Sitter quantum gravity.