Wormholes from averaging over states

An important question about black holes is to what extent a typical pure state differs from the ensemble average. We show that this can be answered within semi-classical gravity. focus on quantum deviation, which measures fluctuations in expectation value of an operator states. For large class ensembles and observables, these are calculated by correlation function eternal hole background, reliably This implements idea [arXiv:2002.02971] wormholes arise averages over states rather than theories. As application, we calculate size long-time $\langle A(t) A(0)\rangle$.