World-Sheet Duality, Space-Time Foam, and the Quantum Fate of a Stringy Black Hole

We interpret Minkowski black holes as world-sheet spikes which are related by worldsheet duality to vortices that correspond to Euclidean black holes. These world-sheet defects induce defects in the gauge fields of the corresponding coset Wess-Zumino descriptions of spherically-symmetric black holes. The low-temperature target space-time foam is a Minkowski black hole (spike) plasma with confined Euclidean black holes (vortices). The high-temperature phase is a dense vortex plasma described by a topological gauge field theory on the world-sheet, which possesses enhanced symmetry as in the target space-time singularity at the core of a black hole. Quantum decay via higher-genus effects induces a back-reaction which causes a Minkowski black hole to lose mass until it is indistinguishable from intrinsic fluctuations in the space-time foam. CERN-TH.6534/92 ACT-12/92 CTP-TAMU-47/92 June 1992 † Permanent address : Center for Theoretical Physics, Dept. of Physics, Texas A & M University, College Station, TX 77843-4242, USA, and Astroparticle Physics Group, Houston Advanced Research Center (HARC), The Woodlands, TX 77381, USA.