Density matrix of black hole radiation

Hawking s model of black hole evaporation is not unitary and leads to a mixed density matrix for the emitted radiation while the Page model describes a unitary evaporation process in which the density matrix evolves from an almost thermal state to a pure state We compare a recently proposed model of semiclassical black hole evaporation to the two established models In particular we study the density matrix of the outgoing radiation and determine how the magnitude of the off diagonal corrections differs for the three