Regular magnetic black holes with anti-de Sitter cores in scalar-tensor gravity with nonlinear electrodynamics: ghost-free construction and axial stability

Rustam Ibadov; Najibullokhon Shukurullokhon

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arXiv · 2610.28670

Regular magnetic black holes with anti-de Sitter cores in scalar-tensor gravity with nonlinear electrodynamics: ghost-free construction and axial stability

Rustam Ibadov·Najibullokhon Shukurullokhon

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Abstract

We construct static, asymptotically flat regular black holes in Einstein-frame scalar--tensor gravity, sourced by a canonical scalar coupled to magnetic nonlinear electrodynamics. Prescribing the density and scalar profiles, we reconstruct the metric, the scalar--photon coupling and the potential. Regularity requires the mass function to vanish at the centre, which fixes the ADM mass, and the central $r^2$ growth of the density to be balanced by the scalar gradient energy. The solutions have an anti-de Sitter core supported by a negative potential and a nearly Reissner--Nordström exterior; the no-ghost condition confines the magnetic charge to a window that closes at a finite core depth. Axial perturbations reduce to a symmetric two-channel master system whose positive-definite potential guarantees mode stability; spectral and time-domain quasinormal frequencies agree. An angular Laplacian instability near the centre can be hidden behind the inner horizon, which excludes horizonless solutions.

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Rustam Ibadov, Najibullokhon Shukurullokhon. 2026-10-17. Regular magnetic black holes with anti-de Sitter cores in scalar-tensor gravity with nonlinear electrodynamics: ghost-free construction and axial stability. https://arxiv.org/abs/2610.28670

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