Classifying boundary conditions in JT gravity: from energy-branes to $\alpha$-branes

TL;DR

This paper classifies boundary conditions in JT gravity, exploring their implications for matrix models, black hole physics, and cosmology, and discusses their exact quantization and ensemble interpretations.

Contribution

It provides a comprehensive classification of boundary conditions in JT gravity and analyzes their effects on the theory's matrix model, factorization, and physical interpretations.

Findings

New boundary conditions reveal diverse matrix integral behaviors

Boundary conditions influence factorization and ensemble averaging

Connections to near-extremal black holes and cosmological models

Abstract

We classify the possible boundary conditions in JT gravity and discuss their exact quantization. Each boundary condition that we study will reveal new features in JT gravity related to its matrix integral interpretation, its factorization properties and ensemble averaging interpretation, the definition of the theory at finite cutoff, its relation to the physics of near-extremal black holes and, finally, its role as a two-dimensional model of cosmology.