QM Research Seminar: Ensemble averaged gravity and a measure of 2d CFTs

Recent insights from 2d quantum gravity and challenges in the holographic description of semiclassical gravity have strengthened a picture of pure gravity as a coarse-grained theory. Yet, it is still unknown how to construct an ensemble that, when averaged over, reproduces semiclassical gravity. In this talk, I will present this new picture of gravity, and some recent attempts to construct an ensemble in 3d gravity within the AdS/CFT framework. In particular, we will focus on a recent attempt to construct a maximally ignorant ensemble of 2d CFTs, deriving some new results on the spectrum of CFTs, and what this implies for gravity.