On the Perturbations of String-Theoretic Black Holes

TL;DR

This paper analyzes how string-intrinsic effects influence the perturbations, stability, and scattering of string-theoretic black holes, revealing significant differences from classical general relativity black holes and potential constraints on string coupling.

Contribution

It generalizes Chandrasekhar's method to string-theoretic black holes, deriving explicit axial potential barriers and highlighting effects of the dilaton field on stability and scattering.

Findings

String-intrinsic effects significantly alter black hole perturbations.

Potential barriers can become negative for certain dilaton values.

Results may constrain the string coupling constant.

Abstract

The perturbations of string-theoretic black holes are analyzed by generalizing the method of Chandrasekhar. Attention is focussed on the case of the recently considered charged string-theoretic black hole solutions as a representative example. It is shown that string-intrinsic effects greatly alter the perturbed motions of the string-theoretic black holes as compared to the perturbed motions of black hole solutions of the field equations of general relativity, the consequences of which bear on the questions of the scattering behavior and the stability of string-theoretic black holes. The explicit forms of the axial potential barriers surrounding the string-theoretic black hole are derived. It is demonstrated that one of these, for sufficiently negative values of the asymptotic value of the dilaton field, will inevitably become negative in turn, in marked contrast to the potentials surrounding the static black holes of general relativity. Such potentials may in principle be used in some cases to obtain approximate constraints on the value of the string coupling constant. The application of the perturbation analysis to the case of two-dimensional string-theoretic black holes is discussed.