Chern-Simons Theory and Three-Dimensional Gravity

As first noticed by Achúcarro and Townsend, and subsequently developed by Witten, the topological nature of three-dimensional general relativity can be made explicit by rewriting the theory as a Chern-Simons theory. Chern-Simons theories are a family of topological gauge theories with an extensively studied quantization, so this formulation opens up a promising pathway towards the quantization of gravity. The objective of this essay is to explore the relationship between three-dimensional gravity and Chern-Simons theory, first at the classical level and then in the context of dS3 quantum gravity.