Properties of Naked Black Holes

TL;DR

This paper explores the unique properties of naked black holes in string theory, highlighting their large tidal forces, the effects on infalling matter, and the stability of their classical backgrounds despite external curvature changes.

Contribution

It provides a detailed analysis of the tidal forces and matter interactions of naked black holes, revealing their stability and the role of dilaton stress-energy in these phenomena.

Findings

Large tidal forces due to dilaton stress-energy

Infalling strings are highly excited but remain small

Small matter infall can cause external curvature to become large

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.