A holographic dual of a 2d topological gravity model to an ensemble of boundary conditions in an open/closed TQFT

2d TQFT and baby universes

We extend a 2d topological gravity model of marolf and maxfieldto have as its bulk action any open/closed topological quantum field theory (tqft) obeying atiyah s axioms.The gravity model is then holographically dual to an ensemble of boundary conditions in an open/closed tqft without gravity.We find that the tqft hilbert space splits into sectors, between which correlators of boundaryobservables factorize, and that the corresponding sectors of the boundary theory have dimensions independently chosen from different poissondistributions.