Stability analysis and absorption cross-section in three-dimensional black string

TL;DR

This paper analyzes the stability and absorption properties of a three-dimensional black string, revealing non-propagating string fields, a decoupled dilaton equation, and calculating absorption cross-sections for dilaton and scalar fields.

Contribution

It introduces a new gauge to disentangle dilaton mixing, derives a decoupled dilaton equation, and computes absorption cross-sections, advancing understanding of black string perturbations.

Findings

Black string is stable under perturbations.

Dilaton and scalar absorption cross-sections are calculated.

Non-propagating string fields except dilaton are identified.

Abstract

It is shown that all string fields except dilaton are non-propagating in the (2+1)-dimensional black string. One finds that the perturbation around the black string reveals a mixing between the dilaton and other fields. Under the new gauge(dilaton gauge), we disentangle this mixing and obtain one decoupled dilaton equation. It turns out that this black string is stable. From the scattering of dilaton off the neutral black string(N=0), we find the absorption cross-section. Further the absorption cross-section for minimally coupled scalar is obtained and we compared it with that of dilaton.