Nonthermal radiation of evaporating black holes

Abstract

Black hole (BH) evaporation is caused by creation of entangled particle-antiparticle pairs near the event horizon, with one carrying positive energy to infinity and the other carrying negative energy into the BH. Since under the event horizon, particles always move toward the BH center, they can only be absorbed but not emitted at the center. This breaks absorption-emission symmetry and, as a result, annihilation of the particle at the BH center is described by a non-Hermitian Hamiltonian. We show that due to entanglement between photons moving inside and outside the event horizon, nonunitary absorption of the negative energy photons near the BH center, alters the outgoing radiation. As a result, radiation of the evaporating BH is not thermal; it carries information about BH interior, and entropy is preserved during evaporation.