Self-gravitating strings and quantum effects in two-dimensional gravity

TL;DR

This paper explores self-gravitating string configurations in two-dimensional dilaton gravity, deriving analytic solutions and analyzing quantum effects, including background radiation analogous to black hole thermodynamics.

Contribution

It provides the first analytic solutions for winding strings in two-dimensional dilaton gravity and examines quantum effects using the RST model.

Findings

Derived analytic solutions for winding strings in 2D gravity.

Analyzed the geometry of self-gravitating strings near the bound state surface.

Found quantum effects include background radiation with temperature matching the strings.

Abstract

It is expected that when the string coupling is taken to be sufficiently small, a black hole turns into a bound state of self-gravitating fundamental strings. This state would be described by winding strings wrapping around the Euclidean time circle, known as the Horowitz-Polchinski solution. In this paper, we study such a self-gravitating string configuration in two-dimensional dilaton gravity theories. We first derive an analytic expression of the solution describing a winding string in two-dimensions and investigate in detail the geometry of this solution. Our winding string solution in two dimensions describes the geometry near the surface of the bound state of self-gravitating strings in the large-dimension limit, much like a two-dimensional black hole describes the near horizon geometry of the Schwarzschild black hole in the large-dimension limit. To study quantum effects around self-gravitating strings, we obtain an analytic solution of winding strings in the RST model. In a similar fashion to the Hartle-Hawking vacuum around a black hole, our string solution in the RST model contains the background radiation, whose temperature is the same as that of the winding strings.