An Apology for AdS3

by Massimo Porrati (New York University)

Tuesday 27 Sept 2016, 15:00 → 17:00 Europe/Rome

The talk will review well known unsolved questions in quantum
gravity, such as the need for a completion at high energies and the
absence of non-perturbative local observables. It will explain how
gravity in three space-time dimension, on the negatively-curved
maximally symmetric background called 3D Anti de Sitter space
(Ad3), retains some of its most puzzling features in a vastly
simplified context. Among the former are the presence of black
holes and infinite-dimensional asymptotic symmetries as well as
the absence of local observables; among the latter, the absence of
local dynamics. I will explain how to use asymptotic symmetries
to recover the celebrated Bekenstein-Hawking formula for black
hole entropy from a statistical-mechanics type of microstate
counting, which uses only very general properties of quantum
gravity in AdS3. The last part of the talk will briefly describe
certain conceptual aspects of gravity in 3D that require a more
technical understanding of the theory.

2016_09_27_Porrati_slides.pdf