1:30 pm MCP 201
Emergent unitarity in de Sitter from matrix integrals - Jordan Cotler, Stanford University
I will discuss Jackiw-Teitelboim gravity with positive cosmological constant as a model for de Sitter quantum gravity. We will explore the quantum mechanics of the model, and show that there is a Hilbert space of asymptotic states at past and future infinity, along with an S-matrix encoding infinite-time evolution. This evolution is not unitary, although it is unitary on a subspace of asymptotic states, up to non-perturbative corrections. This non-unitary is due to universes which evolve into a crunch singularity. We also study topology-changing processes including the nucleation of baby universes. There is significant evidence that this 1+1 dimensional model is dual to a 0+0 dimensional matrix integral. We find that the Hilbert space and time evolution comprising the 1+1D de Sitter physics arise rather robustly from universal properties of the level repulsion of eigenvalues in the random matrix theory.