Charged Scalar Perturbations around Garfinkle-Horowitz-Strominger Black Holes

TL;DR

This paper investigates the stability of Garfinkle-Horowitz-Strominger black holes under charged scalar perturbations, demonstrating their stability and absence of superradiant instability through numerical analysis.

Contribution

It introduces efficient numerical methods for analyzing charged scalar perturbations and establishes the stability of GHS black holes against such perturbations, contrasting with other black hole types.

Findings

GHS black holes are stable under charged scalar perturbations.

The continued fraction and asymptotic iteration methods are effective for frequency domain analysis.

No superradiant instability occurs in GHS black holes.

Abstract

We examine the stability of the Garfinkle-Horowitz-Strominger (GHS) black hole under charged scalar perturbations. We find that different from the neutral scalar field perturbations, only two numerical methods, such as the continued fraction method and the asymptotic iteration method, can keep high efficiency and accuracy requirements in the frequency domain computations. The comparisons of the efficiency between these two methods have also been done. Employing the appropriate numerical method, we show that the GHS black hole is always stable against charged scalar perturbations. This is different from the result obtained in the de Sitter and Anti-de Sitter black holes. Furthermore we argue that in the GHS black hole background there is no amplification of the incident charged scalar wave to cause the superradiance, so that the superradiant instability cannot exist in this spacetime.