Tachyon Splits the (d = 2 String) Black Hole Horizon and Turns it Singular

TL;DR

This paper finds that including tachyon back reaction in a 2D string black hole causes the horizon to split into two and introduces new singularities, suggesting significant modifications to black hole structure.

Contribution

It provides a static solution incorporating tachyon back reaction in 2D string theory, revealing horizon splitting and new singularities.

Findings

Horizon splits into two when tachyon is included.

Curvature scalar develops new singularities at horizons.

Features likely persist with potential V(T) present.

Abstract

We present a static solution for $d = 2$ critical string theory including the tachyon $T$ but not its potential $V(T)$. This solution thus incorporates tachyon back reaction and, when $T = 0$, reduces to the black hole solution. When $T \neq 0$ one finds that (1) the Schwarzschild horizon of the above black hole splits into two, resembling Reissner-Nordstrom horizons and (2) the curvature scalar develops new singularities at the horizons. These features, as we argue, will persist even with $V(T)$ present. Some possible methods for removing these singularities are discussed.