Quasinormal modes and greybody factors of charge black hole in bumblebee gravity model

TL;DR

This paper studies how perturbations and quasinormal modes of charged black holes in Einstein-bumblebee gravity are affected by Lorentz violation and charge, revealing their influence on effective potentials, greybody factors, and shadow radii.

Contribution

It introduces analysis of perturbations, greybody factors, and QNMs of RNdS and RNAdS-like black holes within Einstein-bumblebee gravity, highlighting the effects of Lorentz violation and charge.

Findings

Increasing Lorentz violation parameter L decreases effective potential for RNdS-like black holes.

Charge Q reduces the effective potential for all perturbations in both black hole types.

Higher effective potential correlates with lower greybody factors.

Abstract

In this paper, we investigate the Dirac field, scalar field and electromagnetic field perturbations of Reissner-Nordstorm-de Sitter (RNdS) and Reissner-Nordstorm-(anti)-de Sitter (RNAdS)-like black holes within the frame work of Einstein-bumblebee gravity. The effective potential, greybody factor and quasinormal modes (QNMs) are also explored by using Dirac equation, Klein-Gordon equation and Maxwell's equation. We find that for RNdS-like black hole increasing the Lorentz violation parameter $L$ consistently leads to decrease in the effective potential for all types of perturbations but for RNAdS case the influence of $L$ varies depending on the types of perturbation. Further for both RNdS and RNAdS-like black holes, increasing charge $Q$ reduces the effective potential in all the perturbations. The greybody factors of all the types of perturbations are also discussed. The results show that the greybody factors depend on the shape of the effective potential: higher (lower) potentials gives lower (higher) greybody factors. The QNMs frequencies of RNdS-like black hole for the massless field perturbations are discussed by using 6th order WKB approximation and Pad\'e approximation. We also analyze the time-domain profiles of the perturbations. The effects of Lorentz violation parameter $L$ and charge $Q$ to the photon sphere radius and shadow radius are also discussed. It is noted that increasing $Q$ and $L$ reduce the rise of shadow radius for RNdS-like black hole.