Chandrasekhar separation ansatz and the generalized total angular\n momentum for the Dirac equation in the Kerr-Newman metric

In this paper we compute the square root of the generalized squared total\nangular momentum operator $J$ for a Dirac particle in the Kerr-Newman metric.\nThe separation constant $\\lambda$ arising from the Chandrasekahr separation\nansatz turns out to be the eigenvalue of $J$. After proving that $J$ is a\nsymmetry operator, we show the completeness of Chandrasekhar Ansatz for the\nDirac equation in oblate spheroidal coordinates and derive an explicit formula\nfor the propagator $e^{-itH}$.\n