On the charge-to-mass ratio for self-gravitating systems of scalar and electromagnetic fields

TL;DR

This paper establishes an exact upper bound on the charge-to-mass ratio for a specific family of static, spherically symmetric scalar hairy black holes with electric charge, contributing to understanding their physical limits.

Contribution

It provides a rigorous proof of the precise upper limit of the charge-to-mass ratio in scalar hairy black holes with electric charge, a novel result in black hole physics.

Findings

Charge-to-mass ratio has an exact upper bound of approximately 1.06.

The bound applies to static, asymptotically flat, spherically symmetric scalar hairy black holes.

The result enhances understanding of the physical properties of charged scalar black holes.

Abstract

We prove that in the family of static, asymptotically flat, spherically symmetric scalar hairy black holes with the central electric charge, the set of the charge-to-mass ratios has the exact upper bound $3\sqrt{2}/4\approx1.06$.