1991/11/28 by C. Callan, S. Giddings, J. Harvey +1 · 2 citations
Physics and Astronomy · #hep-th
paper · pdf · doi:10.1103/physrevd.45.r1005
published as Phys.Rev.D45:1005-1009,1992 · 14 pages
arxiv created 1991/11/28 · arxiv updated 2009/11/30
A renormalizable theory of quantum gravity coupled to a dilaton and conformal matter in two space-time dimensions is analyzed. The theory is shown to be exactly solvable classically. Included among the exact classical solutions are configurations describing the formation of a black hole by collapsing matter. The problem of Hawking radiation and backreaction of the metric is analyzed to leading order in a 1/N expansion, where N is the number of matter fields. The results suggest that the collapsing matter radiates away all of its energy before an event horizon has a chance to form, and black holes thereby disappear from the quantum mechanical spectrum. It is argued that the matter asymptotically approaches a zero-energy ``bound state'' which can carry global quantum numbers and that a unitary S-matrix including such states should exist.