Cosmic ER=EPR in dS/CFT
Jordan Cotler, Andrew Strominger
TL;DR
This work extends the ER=EPR paradigm to global de Sitter space within dS/CFT by showing that the bulk exists as an entangled state of two boundary CFTs, with the Euclidean vacuum realized as a thermofield double at imaginary temperature. Using a quasinormal mode basis, the authors explicitly construct the bulk vacua, derive the northern density matrix as a thermal state of the static patch, and provide a precise boundary dual in terms of two coupled CFT$_3$s whose states form a thermofield double. The global dS$_4$ Hilbert space is shown to be isomorphic to the tensor product of two CFT$_3$ Hilbert spaces, with bulk operators and correlators expressible in terms of CFT$_3$ operators acting on both copies. The results illuminate how spacetime geometry and thermality emerge from quantum entanglement in holography and suggest connections to disorder-averaged CFT constructions and time's holographic emergence.
Abstract
In the dS/CFT correspondence, bulk states on global spacelike slices of de Sitter space are dual to (in general) entangled states in the tensor product of the dual CFT Hilbert space with itself. We show, using a quasinormal mode basis, that the Euclidean vacuum (for free scalars in a certain mass range) is a thermofield double state in the dual CFT description, and that the global de Sitter geometry emerges from quantum entanglement between two copies of the CFT. Tracing over one copy of the CFT produces a mixed thermal state describing a single static causal diamond.
