Beam-like Excitations of Kerr-Schild Geometry and Semiclassical Mechanism of Black-Hole Evaporation

Abstract

It has been observed that exact solutions for electromagnetic (EM) excitations of the Kerr-Schild (KS) geometry form outgoing beams which have very strong back reaction to metric and break the black hole horizon. As a result, interaction of a black hole with nearby electromagnetic field and electromagnetic vacuum has to cover the horizon by a set of fluctuating microholes. We integrate and analyze the Debney-Kerr-Schild equations for electromagnetic excitations of a black-hole and obtain that the exact solutions for outgoing radiation contain two related but radically different components which shed light on a possible semi-classical mechanism of black-hole evaporation: a) first component consists of the singular beam pulses which perforate horizon, breaking its impenetrability, and b) another component is regular and responsible for the loss of mass similar to the known Vaidya `shining star' radiation. We show also that the mysterious twosheeted twistor structure of the Kerr-Schild geometry corresponds to a holographic structure of quantum black hole spacetimes predicted by Stephens, t' Hooft and Whiting. The resulting Kerr-Schild geometry of fluctuating twistor-beams takes an intermediate position between the classical and quantum gravity.