Abstract: 

In this talk, I will discuss an information paradox in black hole physics where the entanglement entropy across a two-sided black hole can become negative when inserting a large number of matter excitations behind the black hole horizon. First posed by Lin, Maldacena, Rosenberg, and Shan in two-sided BPS black holes in SUSY JT gravity, I will show this paradox extends to non-SUSY JT gravity with matter as well. Using the newly defined semi-quenched entropy, I will demonstrate how positivity is rescued. In the bulk, the resolution involves a mapping to an effective JT gravity without matter theory and a resummation of topologies of higher genera. On the boundary, the resolution involves zooming in on the edge of the eigenvalue spectrum of the dual matrix model called the Airy limit. Going beyond the Airy limit by adding more matter excitations, we show that the semi-quenched entropy remains positive by a novel mechanism called the one-eigenvalue instanton. This talk is Part II of a talk given by Stefano Antonini.