Aspects of Jackiw-Teitelboim Gravity in Anti-de Sitter and de Sitter spacetime

TL;DR

This paper explores Jackiw-Teitelboim gravity in AdS and dS spacetimes, analyzing path integrals, tunneling processes, and holographic duals involving Random Matrix Theory and SYK models, revealing new insights into quantum cosmology and holography.

Contribution

It introduces a detailed analysis of JT gravity in AdS and dS, proposing modifications to holographic duals and addressing divergences in moduli space integrals.

Findings

Path integrals produce Hartle-Hawking wave functions and tunneling amplitudes.

Modified holography with SYK theory can potentially resolve divergences.

Quantum perturbations may show departures from scale invariance.

Abstract

We discuss JT gravity in AdS and dS space in the second order formalism. For the pure dS JT theory without matter, we show that the path integral gives rise in general to the Hartle-Hawking wave function which describes an arbitrary number of disconnected universes produced by tunnelling "from nothing", or to transition amplitudes which describe the tunnelling of an initial state consisting of several contracting universes to a final state of several expanding universes. These processes can be described by a hologram consisting of Random Matrix Theory (RMT) or, we suggest, after some modification on the gravity side, by a hologram with the RMT being replaced by SYK theory. In the presence of matter, we discuss the double trumpet path integral and argue that with suitable twisted boundary conditions, a divergence in the moduli space integral can be avoided and the system can tunnel from a contracting phase to an expanding one avoiding a potential big bang/big crunch singularity. The resulting spectrum of quantum perturbations which are produced can exhibit interesting departures from scale invariance. We also show that the divergence in moduli space can be avoided for suitable correlators which involve different boundaries in the AdS/dS cases, and suggest that a hologram consisting of the SYK theory with additional matter could get rid of these divergences in general. Finally, we analyse the AdS double trumpet geometry and show that going to the micro-canonical ensemble instead of the canonical one, for the spectral form factor, does not get rid of the divergence in moduli space.