Black Holes Coupled to a Massive Dilaton

TL;DR

This paper explores the properties of charged black holes coupled to a massive dilaton, revealing size-dependent behaviors, the existence of wormholes, and unique repulsive interactions among extremal black holes.

Contribution

It provides the first detailed analysis of black holes with a massive dilaton, showing size-dependent solutions, wormhole formation, and novel extremal black hole interactions.

Findings

Large black holes resemble Reissner-Nordström solutions.

Small black holes resemble massless dilaton solutions.

Extremal black holes repel each other and are quantum mechanically unstable.

Abstract

We investigate charged black holes coupled to a massive dilaton. It is shown that black holes which are large compared to the Compton wavelength of the dilaton resemble the Reissner-Nordstr\"om solution, while those which are smaller than this scale resemble the massless dilaton solutions. Black holes of order the Compton wavelength of the dilaton can have wormholes outside the event horizon in the string metric. Unlike all previous black hole solutions, nearly extremal and extremal black holes (of any size) repel each other. We argue that extremal black holes are quantum mechanically unstable to decay into several widely separated black holes. We present analytic arguments and extensive numerical results to support these conclusions.