Quasinormal modes and greybody factors of magnetically charged de Sitter black holes probed by massless external fields in Einstein Euler Heisenberg gravity

TL;DR

This study analyzes quasinormal modes and greybody factors of magnetically charged de Sitter black holes in Einstein Euler-Heisenberg gravity, revealing how parameters like charge, cosmological constant, and coupling influence black hole perturbations and radiation properties.

Contribution

It provides new calculations of quasinormal frequencies and greybody factors for magnetically charged de Sitter black holes in Einstein Euler-Heisenberg gravity, using multiple numerical methods for validation.

Findings

Good agreement between AIM and WKB methods for QNFs.

Cross-checked QNFs with Bernstein spectral method for scalar perturbations.

Parameters like magnetic charge and coupling significantly affect greybody factors.

Abstract

This paper investigates the perturbation dynamics of massless scalar and electromagnetic fields on magnetically charged de Sitter (dS) black holes within the framework of string-inspired Euler-Heisenberg (EH) gravity. We calculate the quasinormal frequencies (QNFs) and discuss the influences of black hole magnetic charge $Q_{\mathrm{m}}$, the cosmological constant $\Lambda$, coupling parameter $\epsilon$ and multipole number $l$ on QNFs, emphasizing the relationships between these parameters and quasinormal modes (QNMs) behavior. We find that the results obtained through the asymptotic iteration method (AIM) are in good agreement with those obtained by the WKB method. Importantly, the Bernstein spectral method is employed as a rigorous cross-check for QNFs in the $l=0$ scalar perturbation sector, where the WKB approximation is often unreliable. The greybody factor (GFs) is calculated using WKB method. The effects of the parameters $Q_{\mathrm{m}}$ and $\epsilon$ on the greybody factor are also studied.