UC Berkeley

In this dissertation, we explore these two complementary approaches to quantum gravity – holography as a bottom-up perspective and string theory as a top-down framework.

On the holography side, we study two novel extensions of the AdS/CFT duality – TT deformed CFTs and their gravitational duals, and a two-dimensional BCFT with two conformal boundaries dual to AdS spacetime with two End-of-the-World branes that can intersect at a defect. We also develop a bulk flow procedure that can be interpreted as generating a sequence of coarse-grained holographic states. We demonstrate the existence of a novel inside-out entanglement island for the eternally inflating multiverse. We compute the entanglement entropy of free fermions in the presence of a partially transmitting boundary and use it to study entanglement islands for a blackhole with non-trivial graybody factors.

On the string theory side, we study non-perturbative effects in minimal string theory. We compute various instanton contributions like the ZZ cylinder, the ZZ annulus one-point function, and the disk two-point function using string field theory. We also match these to results from the dual matrix model or matrix quantum mechanics.