Abstract: ‘Recent works have proposed that pure gravity in $AdS_3$ may be understood as an ensemble average over approximate $\mathrm{CFT}_2$ data. We explore the spectral content of this idea by constructing a “Cardy random matrix theory”: an RMT whose only bootstrap input is coarse-grained $\mathbb{S}$-modular invariance. When we prescribe the vacuum to be the only state below the black-hole threshold, … Read More

Abstract:   We explain the necessary and sufficient conditions for the gravitational path integral (GPI) to admit an interpretation in terms of (i) an inner product in the Hilbert space of open/closed universes or (ii) a statistical average of boundary observables. The conditions needed for (i) are necessary but not sufficient for (ii).  The conditions are  are equivalent to  positivity constraints … Read More