Dilaton Black Holes with Electric Charge

TL;DR

This paper explores static spherically symmetric solutions in Einstein-Maxwell-dilaton gravity, revealing how the dilaton charge influences black hole geometry and identifying conditions under which black holes cannot form due to electric charge constraints.

Contribution

It introduces a generalized class of dilaton black hole solutions with an additional dilaton charge parameter, extending previous models and analyzing their geometric and physical properties.

Findings

Dilaton charge affects space-time geometry of black holes.

Scalar curvature diverges at horizons in most cases.

Existence of a finite charge interval where black holes cannot form.

Abstract

Static spherically symmetric solutions of the Einstein-Maxwell gravity with the dilaton field are described. The solutions correspond to black holes and are generalizations of the previously known dilaton black hole solution. In addition to mass and electric charge these solutions are labeled by a new parameter, the dilaton charge of the black hole. Different effects of the dilaton charge on the geometry of space-time of such black holes are studied. It is shown that in most cases the scalar curvature is divergent at the horizons. Another feature of the dilaton black hole is that there is a finite interval of values of electric charge for which no black hole can exist.