HAWKING RADIATION FOR NONMINIMALLY COUPLED MATTER FROM GENERALIZED 2-D BLACK-HOLE MODELS

It is well known that spherically symmetric reduction of general relat ivity (SSG) leads to non-minimally coupled scalar matter. We generaliz e (and correct) recent results to Hawking radiation for a class of dil aton models which share with the Schwarzschild black hole non-minimal coupling of scalar fields and the basic global structure. An inherent ambiguity of such models (if they differ from SSG) is discussed. Howev er, for SSG we obtain the rather disquieting result of a negative Hawk ing flux at infinity, if the usual recipe for such calculations is app lied.