Scalarized dyonic black holes in vector-tensor Horndeski gravity

TL;DR

This paper investigates scalarized dyonic black holes within a vector-tensor Horndeski gravity framework, revealing instabilities in Reissner-Nordstrom solutions and the emergence of hairy black holes with scalar hair at critical couplings.

Contribution

It introduces a non-minimally coupled scalar field into vector-tensor Horndeski gravity, demonstrating the formation of scalarized black holes from instabilities in known solutions.

Findings

Reissner-Nordstrom solutions become unstable and bifurcate into hairy black holes.

Scalar hair appears at specific non-minimal coupling values.

Critical phenomena define the existence domain of these black holes.

Abstract

The vector-tensor Horndeski theory is supplemented by a real, massless scalar field non-minimally coupled to the Horndeski interaction term. The generic dyonic Reissner-Nordstrom solutions characterized by electric and magnetic charges, acquire an instability and bifurcate into electromagnetically charged solutions presenting an horizon and a cloud of scalar hairs at specific values of the non-minimal coupling constant. These hairy black holes are studied in terms of the physical parameters of the model and the critical phenomena limiting their domain of existence are discussed.