Radial perturbations of charged wormholes

Ellis-Bronnikov wormholes suffer from an unstable radial mode. Here we investigate the evolution of the unstable mode(s) for charged wormholes. We show that the instability remains in the presence of charge, but exhibits a very fast decrease to zero. We hereby make a full study of the spectrum of the unstable radial modes. For so-called supercritical wormholes, two purely imaginary unstable modes merge and continue with degenerate imaginary parts and opposite real parts. By analogy, we conjecture an analogous behavior for rotating chargeless wormholes.