Quasinormal Modes of a Massive Scalar Field in 4D Einstein--Gauss--Bonnet Black Hole Spacetimes

TL;DR

This paper investigates how a massive scalar field behaves around 4D Einstein-Gauss-Bonnet black holes, revealing that increased field mass leads to longer-lived modes and that the Gauss-Bonnet coupling has a mild effect within stability constraints.

Contribution

It provides the first detailed analysis of quasinormal modes and scattering properties of massive scalar fields in 4D Einstein-Gauss-Bonnet black hole spacetimes, highlighting the impact of field mass and coupling.

Findings

Higher field mass reduces damping and leads to long-lived quasi-resonances.

Larger potential barriers suppress transmission and low-frequency absorption.

Gauss-Bonnet coupling has a mild impact within the stable parameter range.

Abstract

We analyze quasinormal modes, grey-body factors, and absorption cross-sections of a massive scalar field in four-dimensional Einstein--Gauss--Bonnet black-hole spacetimes within a stability-constrained coupling window. High-order WKB-Pad\'e spectra show that increasing field mass typically reduces damping and drives the system toward long-lived, quasi-resonant behavior. The scattering sector follows the same potential-barrier physics: larger effective barriers suppress transmission and low-frequency absorption, while the Gauss--Bonnet coupling has a comparatively mild impact over the stable range. These results provide a compact baseline for massive-field spectroscopy in higher-curvature black-hole backgrounds.