Ensemble averaging in AdS/CFT

I will discuss two recent proposals that shed some light on the role of the ensemble in the semiclassical description of quantum gravity in AdS. The first one (2202.01372) highlights the role of quantum chaos in the black hole band by arguing that the ensemble does not affect the physics below the Hawking-Page transition. More ambitiously, the second proposal (2111.07863) adds a new class of spacetime boundary into the JT path integral which collapses the JT ensemble into a given draw, restoring factorization to all orders in the topological expansion.