Speaker: Marek Liska

Title: Semiclassical spacetime thermodynamics

Abstract: I outline the recovery of semiclassical gravitational dynamics from entanglement equilibrium of local causal horizons. Due to backreaction of quantum fields, gravitational entanglement entropy acquires corrections encoded in the conformal anomaly. Though entropy is no longer simply proportional to area, the universal nature of the anomaly still ensures a robust entropy prescription that can be obtained without invoking the gravitational Lagrangian. Then, gravitational dynamics follows from equilibrium conditions in a self-contained and internally consistent way. Since the resulting theory includes a non-minimally coupled scalar field, I further discuss the peculiarities of entropy in such theories. While the talk focuses on a tractable 2D setup, I also comment on the physically most relevant 4D case.