Critical energy flux and mass in solvable theories of 2d dilaton gravity

TL;DR

This paper investigates the semiclassical conditions for black hole formation in 2D dilaton gravity models, revealing that critical energy flux and mass depend on initial spacetime configurations and vary across different models.

Contribution

It introduces a unified analysis of critical energy flux and mass in a family of solvable 2D dilaton gravity theories, highlighting the dependence on initial conditions.

Findings

Critical energy flux aligns with Hawking evaporation rate in some models.

Existence of a critical mass $m_{cr}$ that can vanish in certain theories.

Some models exhibit no critical flux or mass thresholds.

Abstract

In this paper we address the issue of determining the semiclassical threshold for black hole formation in the context of a one-parameter family of theories which continuously interpolates between the RST and BPP models. We find that the results depend significantly on the initial static configuration of the spacetime geometry before the influx of matter is turned on. In some cases there is a critical energy density, given by the Hawking rate of evaporation, as well as a critical mass $m_{cr}$ (eventually vanishing). In others there is neither $m_{cr}$ nor a critical flux.