BACK-REACTION AND COMPLEMENTARITY IN 1+1 DILATON GRAVITY

We study radiation from black holes in the effective theory produced b y integrating gravity and the dilaton out of 1 + 1 dilaton gravity, Th e semiclassical wavefunctions for the dressed particles show that the self-interactions produce an unusual renormalization of the frequencie s of outgoing stales. Modes propagating in the dynamical background of an incoming quantum state are seen to acquire large scattering phases that nevertheless conspire, in the absence of self-interactions, to p reserve the thermality of the Hawking radiation, However, the in-out s cattering matrix does not commute with the self-interactions and this could lead to observable corrections to the final state, Finally, our calculations explicitly display the limited validity of the semiclassi cal theory of Hawking radiation and provide support for a formulation of black hole complementarity.