New coordinates for Kerr–Newman black hole radiation

Abstract

A simple coordinate system of Kerr–Newman space–time is introduced. The new coordinates have several attractive properties: the time direction is a Killing vector, the metric is smooth at the horizons, constant-time slices are just flat Euclidean space in radial and satisfy Landau's condition of clock synchronization. The usefulness of the coordinates is demonstrated by calculating the rate at which uncharged particles tunnel across the event horizon. When self-gravitation is taken into account, the radiation deviates from precisely thermal spectrum. The corrected spectrum is consistent with an underlying unitary theory.