Microscopic origin of the entropy of black holes in general relativity

February 6, 2023
4:30pm to 5:30pm


Specialist level
Martín Sasieta
Brandeis University



It has been known for a long time that the local description of the interior of the black hole is in clear tension with its universal entropy, given by the Bekenstein-Hawking formula. In this talk, I will start by constructing an infinite family of semiclassical microstates with smooth interiors in the gravitational effective field theory, which naively overcount the entropy of the black hole. I will then show that the gravitational path integral is able to detect non-orthogonalites between these states via non-perturbative wormhole contributions. I will finally show how to count these states carefully to conclude that the microcanonical Hilbert space spanned by these states is e^S dimensional, where S is the Bekenstein-Hawking entropy. Time permitting, I will talk about holographic complexity at exponential times and I will mention future directions.