Quantum properties of the electron field in Kerr–Newman black hole manifolds

We study some spectral features of the one-particle electron Hamiltonian obtained by separating the Dirac equation in a Kerr–Newman black hole background. We find that the essential spectrum coincides with the whole real line. As a consequence, there is no gap in the spectrum and discrete eigenvalues are not allowed for any value of the black hole charge Q and angular momentum J. Our spectral analysis will be also related to the dissipation of the black hole angular momentum and charge.