Quasinormal Spectra of Fields of Various Spin in Asymptotically de Sitter Black Holes within Generalized Proca Theory

TL;DR

This paper investigates the quasinormal spectra of various spin fields in asymptotically de Sitter black holes within generalized Proca theory, revealing how parameters influence damping and spectrum characteristics.

Contribution

It derives master equations for different spin perturbations and analyzes their spectra, highlighting the effects of Proca hair and other parameters on quasinormal modes.

Findings

Scalar sector, especially $ ext{l}=0$, is most sensitive to metric deformations.

Increasing Proca-hair parameter $Q$ weakens damping near the three-horizon regime.

Time-domain and WKB results agree well for $ ext{l}=1$ modes.

Abstract

We study massless scalar, electromagnetic, and Dirac perturbations of asymptotically de Sitter black holes in generalized Proca theory. These geometries are especially interesting because the Proca sector generates both a primary-hair parameter and an effective cosmological term $\Lambda_{\rm eff}$, thereby reshaping the horizon structure and the size of the static patch. Working on this common hairy background, we derive the master equations for the three spin sectors and analyze their quasinormal spectra by means of Pad\'e-improved WKB calculations supplemented by characteristic time-domain integration. We show that the scalar sector, especially the $\ell=0$ mode, is the most sensitive to metric deformations; increasing the Proca-hair parameter $Q$ weakens the damping as the charged three-horizon regime is approached; $\beta$ hardens the spectrum in the $(\alpha,\beta)$ scan; and increasing $\lambda$ and $c_1$ produces the strongest overall softening. For the neutral scalar $\ell=1$ mode, the time-domain Prony extraction agrees excellently with the WKB results and resolves both the Schwarzschild-like black-hole branch and the de Sitter branch. We also discuss the implications of the exact empty-de Sitter limit for strong cosmic censorship and note that the resulting quasinormal frequencies provide useful input for grey-body factors.