Quasinormal modes of a charged spherically symmetric black hole in bumblebee gravity

Abstract

Lorentz symmetry may be violated at the Planck scale. In the bumblebee model, a vector field acquires a nonzero vacuum expectation value, spontaneously breaking Lorentz symmetry. We study quasinormal modes of a charged spherically symmetric black hole in this framework, focusing on the coupled gravito-electromagnetic perturbations induced by nonminimal coupling. Using the continued fraction and asymptotic iteration methods, we find that the Lorentz-violating parameter shifts the real frequencies of gravitationally-dominated and electromagnetically-dominated modes in opposite directions. The results reveal mixed excitation channels that are absent in the standard Reissner–Nordström limit, offering potential targets for future gravitational-wave ringdown observations.