String Theory seminar - Manus Visser Seminar

Abstract: In their seminal 1977 paper, Gibbons and Hawking applied concepts of quantum statistical mechanics to ensembles containing black holes, finding that a semiclassical saddle point approximation to the partition function recovers the laws of black hole thermodynamics. We will generalise the Gibbons-Hawking method by defining a partition function of a ball of space at fixed proper volume. In the zero-loop approximation the result is the exponential of the Bekenstein-Hawking entropy of the boundary of the ball, indicating the holographic nature of nonperturbative quantum gravity in generic finite volumes of space. Based on the recent work 2212.10607 with Ted Jacobson.