Friday, July 31, 2020 - 2:00 pm
Brandon Rayhaun (Stanford PhD candidate)
I will summarize some of the recent work which aims to settle the question of whether or not pure AdS3 gravity is consistent as a quantum theory. In particular, I'll focus on attempts to resolve two potentially problematic aspects of the Maloney-Witten-Keller (MWK) partition function [1,2], which is thought to be a good starting point for studying the spectrum of the theory: (a) negativities  and (b) continuities in the density of states.
Broadly speaking, to resolve issue (a), people have explored additional contributions to the path integral of 3d quantum gravity which are not accounted for by the MWK partition function, and which are thought to cancel the negativities [4,5]. As for (b), while it appears to rule out the possibility of pure AdS3 gravity being dual to a single compact CFT2, it is actually consistent with it being dual to an ensemble average of such theories. Such an idea has precedence in the context of 2d JT gravity , and there are a variety of papers [7-11] which provide hope that something similar will alleviate the tension brought about by the continuous MWK spectrum. Of course, everything I've said is not without (interesting) subtleties and caveats, and I hope to foster discussion about some of these issues by providing a list of questions I've had in navigating this literature throughout my talk.