Rotating Black Holes in Einstein-Born-Infeld Theory

Abstract: We numerically construct a family of stationary, axisymmetric black hole solutions in Einstein-Born-Infeld theory, incorporating both electric charge and rotation. Our results indicate that when nonlinear electromagnetic effects are weak, rotating BI black holes with fixed spin approach the extremal limit as the electric charge increases. In contrast, strong nonlinear effects lead to the termination of solutions at configurations corresponding to naked singularities. We demonstrate that nonlinear electrodynamics enhances the gyromagnetic ratio relative to that of Kerr-Newman (KN) black holes. Additionally, we analyze the Innermost Stable Circular Orbits (ISCOs) and find that both prograde and retrograde ISCO radii are consistently smaller than those found in KN black holes.