Solution of Dirac equation in Reissner–Nordström de Sitter space

The radial parts of the Dirac equation between the outer black hole horizon and the cosmological horizon are solved in Reissner–Nordstrom de Sitter (RNdS) space numerically. An accurate approximation, the polynomial approximation, is used to approximate the modified tortoise coordinate , which leads to the inverse function and the potential . The potential is replaced by a collection of step functions in sequence. Then the solution of the wave equation as well as the reflection and transmission coefficients is computed by a quantum mechanical method.