String Theory Journal Club

I will explain how to use the quantum Ryu-Takayanagi formula to compute entanglement entropies in pure JT gravity, including all of the perturbative graviton corrections. I will also explain why it is not possible to factorize the gravity Hilbert space in a local way. The tension between defining a local and isometric factorization map motivates the insertion of a "defect operator" into the standard definition of the Renyi entropy. The defect operator has a clear interpretation in the Euclidean replica calculation of the entropy. The contribution of the defect operator to the entanglement entropy matches the area term in the quantum Ryu-Takayanagi formula. Zoom Link: https://mpi-aei.zoom.us/j/95580327312