Revisiting subregion holography using OPE blocks

Abstract: In this short note, we revisit the entanglement wedge representation of AdS$_3$ bulk fields in terms of CFT operator product expansion (OPE) blocks for a general class of blocks. Given a boundary interval and its associated causal diamond, the OPEs involve boundary operators with or without spin, and located either at spacelike or timelike edges of the diamond. Only for a subset of these cases, can the OPE block be dual to a geodesic bulk field. We show that when applied to de Sitter, a suitable combination of Euclidean OPE blocks can represent a dS scalar integrated over the timelike extremal surfaces, which play an important role in defining pseudo-entropy. We also work out some simple higher dimensional examples.