Cloudy black-hole configurations of the composed Einstein-Yang-Mills-Higgs field theory: Analytic treatment

Abstract

Non-Abelian black holes that violate the non-hair conjecture are known to exist in the Einstein-Yang-Mills-Higgs field theory. The onset of hair formation in this composed physical system is marked by the presence of `cloudy' black-hole spacetimes, magnetically charged Reissner-Nordström black holes that support spatially regular linearized field configurations. In the present paper we explore, using {\it analytical} techniques, the physical and mathematical properties of the composed black-hole-linearized-field bound-state configurations of the Einstein-Yang-Mills-Higgs theory. In particular, we derive a remarkably compact analytical formula for the discrete resonance spectrum $\{μ_k\}^{k=\infty}_{k=1}$ of the dimensionless mass-radius parameter $μ\equiv m_{\text{w}} r_+$ that characterizes the cloudy black-hole-field configurations in the regime $1\ll r_+\ll m^{-1}_{\text{w}}$ of small-mass weakly-magnetized black holes (here $r_+$ is the horizon radius of the central supporting black hole and $m_{\text{w}}$ is the mass of the Yang-Mills field due to the Higgs effect). Interestingly, our results reveal that the excited black-hole-field resonances are characterized by the asymptotic $k$-independent dimensionless ratio ${μ_{k+1}/{μ_{k}}}=e^{-{{2π}/{\sqrt{3}}}}$.