On the Mass of Two Dimensional Quantum Black Hole

TL;DR

This paper defines a local black hole mass in a two-dimensional quantum gravity model, analyzing its behavior and showing it decreases along matter shock-waves while remaining constant at past null infinity.

Contribution

It introduces a local mass concept for 2D quantum black holes and analyzes its properties within the CGHS model, extending prior four-dimensional analogues.

Findings

Local mass decreases along matter shock-waves

Mass remains constant at past null infinity

Provides a new tool for analyzing 2D quantum black holes

Abstract

For the two dimensional dilaton-coupled quantum gravity model, we give the local black hole mass, which is an analogue of what was first introduced by Fischler, Morgan and Polchinski in the four dimensional gravitational systems. We analyze the original CGHS model with this local mass and find that the local mass is decreasing in the future direction on the matter shock-wave line, while it stays constant at past null infinity.