Spinning extremal dyonic black holes in $\gamma=1$ Einstein-Maxwell-dilaton theory

TL;DR

This paper introduces a framework for studying extremal spinning dyonic black holes in Einstein-Maxwell-dilaton theory at gamma=1, revealing a family of solutions with equal electric and magnetic charges.

Contribution

It presents the first detailed analysis of extremal dyonic black holes in this theory at gamma=1, including near horizon solutions and conditions for regularity.

Findings

Existence of a one-parameter family of regular extremal black holes with equal charges.

Both perturbative and numerical solutions for near horizon geometries are provided.

Regular solutions are characterized by the equality of magnetic and electric charges.

Abstract

We propose a general framework for the study of asymptotically flat spinning dyonic {\it extremal} black holes (eBHs) in $D=4$ Einstein-Maxwell-dilaton theory. Restricting to the stringy value $\gamma=1$ of the dilaton coupling constant, we report on the existence of a one parameter family of eBHs which are free of pathologies, provided their magnetic and electric charges are equal. An understanding of this condition is found from a study of the near horizon limit of the solutions, both perturbative closed form and numerical solutions being presented.