Observables, Hilbert Spaces and Entropies from the Gravitational Path Integral

Gravitational path integrals can define Hilbert spaces and algebras of bulk observables under a specified set of assumptions. This seminar develops the associated notion of entropy and its state-counting interpretation. In appropriate semiclassical limits, it connects those constructions with the Ryu-Takayanagi formula, providing a bulk interpretation of a result originally motivated by holographic boundary theories.