A Non Degenerate Semi-Classical Lagrangian for Dilaton-Gravity in Two Dimensions

TL;DR

This paper develops a semi-classical model of two-dimensional dilaton-gravity that shows all generic solutions are flat, providing insights into black hole configurations and their classical limits.

Contribution

It introduces a non-degenerate semi-classical Lagrangian for 2D dilaton-gravity, analyzing solutions including black holes and their collapse behavior.

Findings

Classical solutions include black holes.

Semi-classical equations imply flat geometry for generic solutions.

Collapse of matter fields leads to singular solutions.

Abstract

An action for two dimensional gravity conformally coupled to two dilaton-type fields is analysed. Classically, the theory has some exact solutions. These include configurations representing black holes. A semi-classical theory is obtained by assuming that these singular solutions are caused by the collapse of some matter fields. The semi-classical equations of motion reveal then that any generic solution must have a flat geometry.