Area spectra of extreme Kerr and nearly extreme Kerr–Newmann black holes from quasinormal modes

The area spectra of extreme Kerr and nearly extreme Kerr–Newmann black holes are investigated from quasinormal modes via Maggiore’s physical interpretation of quasinormal modes. Using the first law of black hole thermodynamics and the action variable quantization, we arrive at consistent equally spaced area and entropy spectra. Results show that the spectra are irrelevant to the parameters of the black holes and the perturbation fields, which fully agree with Bekensteins original conjecture. In the calculations, we have defined the corresponding Hawking temperatures of the black holes following the suggestion of Mäkelä et al. to avoid the zero temperature and to guarantee the (nearly-) extreme black holes quantizable.