Gravito-Electromagnetic perturbation of higher derivative corrected Kerr-Newman black hole
We study linear gravito-electromagnetic perturbations of a slowly rotating 4-derivative corrected Kerr-Newman (KN) black hole (BH), using a perturbative approach beyond the KN geometry up to first order in angular momentum, first order in the higher-derivative parameters ci, i = 1,2...8, and 14th order in the BH electric charge. We derive the corrected coupled radial master equations for both axial and polar perturbation sectors. We extend the asymptotic iteration method (AIM) to apply to coupled second-order ordinary differential equations (ODEs) and employ it to compute the quasinormal frequencies (QNFs) of the system.Our results show pronounced isospectrality breakings between the two parity sectors, induced by c6,c7 and c8,particularly for high charge BH.This indicate the equations for the two parity sectors lose the transformation symmetry that relates them in the KN case.The very tiny frequency shifts induced by c4 support the interpretation that this parameter represents a redundant degree of freedom in the effective field theory.Finally, we parameterize the QNFs via a analytical fitting procedure for broader applicability.