Black hole minimum size and scalar charge in shift-symmetric theories

TL;DR

This paper investigates how additional shift-symmetric scalar interactions influence the minimum size and scalar charge of black holes, extending understanding of black hole hair in modified gravity theories.

Contribution

It analyzes the effects of extra shift-symmetric interactions on black hole properties beyond the known linear Gauss-Bonnet coupling.

Findings

Additional interactions modify the minimum black hole mass.

Scalar charge depends on the new interactions and black hole parameters.

The structure of hairy black holes is affected by these interactions.

Abstract

It is known that, for shift-symmetric scalars, only a linear coupling with the Gauss-Bonnet invariant can introduce black hole hair. Such hairy black holes have a minimum mass, determined by the coupling of this interaction, and a scalar charge that is uniquely determined by their mass and spin for a fixed value of that coupling. Here we explore how additional shift-symmetric interactions affect the structure of the black hole, the value of the minimum mass, and the scalar charge.