Resonance Spectra of Caged Stringy Black Hole and Its Spectroscopy

TL;DR

This paper uses Maggiore's method with boxed quasinormal modes to analyze the entropy and area spectra of a caged Garfinkle--Horowitz--Strominger black hole, revealing equally spaced spectra independent of black hole parameters.

Contribution

It introduces a novel approach using BQNMs and a confining cavity to determine the quantization of entropy and area spectra of GHS black holes.

Findings

Entropy and area spectra are equally spaced.

Quantization is independent of black hole parameters.

Resonance frequencies are computed via Bessel differential equations.

Abstract

The Maggiore's method (MM), which evaluates the transition frequency that appears in the adiabatic invariant from the highly damped quasinormal mode (QNM) frequencies, is used to investigate the entropy/area spectra of the Garfinkle--Horowitz--Strominger black hole (GHSBH). Instead of the ordinary QNMs, we compute the boxed QNMs (BQNMs) that are the characteristic resonance spectra of the confined scalar fields in the GHSBH geometry. For this purpose, we assume that the GHSBH has a confining cavity (mirror) placed in the vicinity of the event horizon. We then show how the complex resonant frequencies of the caged GHSBH are computed using the Bessel differential equation that arises when the scalar perturbations around the event horizon are considered. Although the entropy/area is characterized by the GHSBH parameters, their quantization is shown to be independent of those parameters. However, both spectra are equally spaced.