Properties of naked black holes

Abstract

We investigate the properties of a class of near-extreme static black hole solutions called naked black holes. These black holes, which occur in string theory, have small curvature invariants but large tidal forces outside their event horizons. We show that these large tidal forces are due to a concentration of dilaton stress-energy near the horizon. We study infalling test strings and find that they are highly excited by the large tidal forces, but remain small. Perhaps most importantly, it turns out that a small amount of infalling matter will cause the curvature invariants to become large outside the horizon. Nevertheless, an exact calculation shows that both the matter trajectories and the classical black hole background are not significantly altered.