A multiverse model in $T^2$ dS wedge holography

Abstract

We construct a multiverse model where empty AdS$_{d+1}$ space is cut off by a pair of accelerated dS$_d$ space universes, at a finite AdS boundary cutoff which we treat as a $T^2$ deformation in the holographic dual, and one in the AdS interior, the IR brane{; and denote the construction as $T^2$ dS wedge holography}. We glue together several copies of this configuration along the UV cutoff and the IR branes in a periodic matter. To provide the model with dynamics similar to those of near Nariai black holes used in other multiverse toy models{, we specialize to $d=2$ and} add dS JT gravity as an intrinsic gravity theory on the IR branes. We then study the entanglement entropy with respect to a finite cutoff observer, who finds a Page curve transition due to an entanglement island connecting the UV cutoff and IR brane. This process involves the coarse-graining of information outside the causally accessible region to the observer. Our model provides an explicit realization of entanglement between IR and UV degrees of freedom encoded in the multiverse.