Analytical Study of a Kerr-Sen Black Hole and a Charged Massive Scalar Field

Abstract

It is reported that Kerr-Newman and Kerr-Sen black holes are unstable to perturbations of charged massive scalar field. In this paper, we study analytically the complex frequencies which characterize charged massive scalar fields in a near-extremal Kerr-Sen black hole. For near-extremal Kerr-Sen black holes and for charged massive scalar fields in the eikonal large-mass $\mathcal{M}\gg \mu$ regime, where $\mathcal{M}$ is the mass of the black hole, and $\mu$ is the mass of the charged scalar field, we have obtained a simple expression for the dimensionless ratio ${\omega }_I/\left({\omega }_R-{\omega }_c\right)$, where ${\omega }_I$ and ${\omega }_R$ are, respectively, the imaginary and real parts of the frequency of the modes, and ${\omega }_c$ is the critical frequency for the onset of super-radiance. We have also found our expression is consistent with the result of Hod [Phys. Rev. D 94, 044036 (2016)] for the case of a near-extremal Kerr-Newman black hole and the result of Zouros and Eardly [Ann. Phys. (N.Y.) 118, 139 (1979)] for the case of neutral scalar fields in the background of a near-extremal Kerr black hole.

18 pages, no figures; v2: references are added, typos are corrected, to be published in Physical Review D. The reference list is slightly different from the journal version

References in corpus (14)

• Instability of the massive Klein-Gordon field on the Kerr spacetime
• Kerr-Newman scalar clouds
• Kerr-Newman black holes with stationary charged scalar clouds
• A new spin on black hole hair
• Kerr-Newman black holes with scalar hair
• Scalar clouds and the superradiant instability regime of Kerr-Newman black hole
• Stationary Charged Scalar Clouds around Black Holes in String Theory
• Analytic treatment of the system of a Kerr-Newman black hole and a charged massive scalar field
• Scalar clouds around Kerr-Sen black holes
• Scalar clouds in charged stringy black hole-mirror system
• Spectroscopy of Rotating Linear Dilaton Black Holes From Boxed Quasinormal Modes
• Eigenvalue spectrum of the spheroidal harmonics: A uniform asymptotic analysis
• Charged black holes in string-inspired gravity: I. Causal structures and responses of the Brans-Dicke field
• Resonance Spectra of Caged Stringy Black Hole and Its Spectroscopy

Cited by in corpus (3)

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• Hidden conformal symmetry of the rotating charged AdS black holes in quadratic $f$($T$) gravity
• Absorption by stringy black holes