QUANTUM-GRAVITY AND NON-UNITARITY IN BLACK-HOLE EVAPORATION

We discuss the relevance of quantum gravitational corrections to the f unctional Schrodinger equation for black hole evaporation. These corre ctions are found from the Wheeler-DeWitt equation through a semiclassi cal expansion scheme. The dominant contribution in the final evaporati on stage, when the black hole approaches the Planck regime, is a term which explicitly violates unitarity in the non-gravitational sector. W hile pure states remain pure, there is an increase in the degree of pu rity for non-pure states in this sector. This result holds irrespectiv e of whether full quantum gravity respects unitarity or not.