Trace anomaly and black holes evaporation

Abstract

A model is proposed to describe a transition from a Schwarzschild black hole of mass $M_0$ to a Schwarzschild black hole of mass $M_1$ $\le M_0$. The basic equations are derived from the non-vacuum Einstein field equations taking a source representing a null scalar field with a nonvanishing trace anomaly. It is shown that the nonvanishing trace anomaly of the scalar field prevents a complete evaporation.