Abstract:
At exponentially low temperatures in the black hole entropy, (doubly) non-perturbative effects are not merely important; they dominate. In this talk, I’ll address this regime using the near-extremal sector universally captured by JT-like theories and its matrix integral description. I’ll begin by explaining how the matrix ensemble generically implies a negative divergence at extremality of the annealed entropy traditionally computed by gravity, and how supersymmetry only qualitatively corrects this. In obtaining the actual thermodynamic quenched entropy via replica trick, I’ll outline how the matrix computation identifies an eigenvalue instanton as the dominant low-temperature contribution to any correlator. In the second part, I’ll describe this instanton’s gravity dual: a class of dynamical branes without free parameters that captures all-genus contributions. Remarkably, in the Airy limit, the genus sum becomes a sum over cusps, and an effective, modified JT theory emerges, whose semiclassical limit describes non-perturbative physics of the original theory.
Based on 2407.20321 and work in progress with Nico Valdes-Meller and Wayne Weng.