From black holes to baby universes in CGHS gravity

We study (CGHS) over cap gravity, a variant of the matterless Callan-Giddings-Harvey-Strominger model. We show that it describes a universal sector of the near horizon perturbations of non-extremal black holes in higher dimensions. In many respects this theory can be viewed as a flat space analog of Jackiw-Teitelboim gravity. The result for the Euclidean path integral implies that (CGHS) over cap is dual to a Gaussian ensemble that we describe in detail. The simplicity of this theory allows us to compute exact quantities such as the quenched free energy and provides a useful playground to study baby universes, averages and factorization. In particular we derive a wormhole = diagonal identity. We also give evidence for the existence of a non-perturbative completion in terms of a matrix model. Finally, flat wormhole solutions in this model are discussed.

Automated summary

The study focuses on cap gravity supergravity, revealing its role in the near-horizon perturbations of non-extremal black holes and its connection to Jackiw-Teitelboim gravity. The model's simplicity allows for exact calculations and exploration of phenomena, as well as proposing a non-perturbative completion in the form of a matrix model. This research also discusses the existence of flat wormhole solutions within this model.