HEP Theory Journal Club

Gravity as an Ensemble Average

Alex Malone

McGill

I will explore the idea that certain theories of gravity in Anti-de Sitter space are dual to an average over an ensemble of quantum theories, rather than to a specific quantum theory. I will describe an average over Narain's family of two-dimensional conformal field theories which describe free bosons on a torus. This result takes the form of a sum over geometries as one would expect in a theory of quantum gravity. But the gravitational theory looks more like a Chern-Simons theory than Einstein gravity.