QUANTUM N=2 SUPERSYMMETRIC BLACK-HOLES IN THE S-T MODEL

We consider axion-free quantum corrected black hole solutions in the c ontext of the heterotic S-T model with half the N = 2, D = 4 supersymm etries unbroken. We express the perturbatively corrected entropy in te rms of the electric and magnetic charges in such a way, that target-sp ace duality invariance is manifest, We also discuss the microscopic or igin of particular quantum black hole configurations, We propose a mic roscopic interpretation in terms of a gas of closed membranes for the instanton corrections to the entropy. (C) 1997 Elsevier Science B.V.