Quasinormal modes for massive charged scalar fields in Reissner-Nordstr\"om dS black holes: anomalous decay rate

TL;DR

This paper investigates the anomalous decay rates of quasinormal modes for massive charged scalar fields in Reissner-Nordström-de Sitter black holes, revealing critical parameters that influence decay behavior and its inversion.

Contribution

It demonstrates that the anomalous decay rate phenomenon extends to charged massive scalar fields and identifies critical values affecting this behavior.

Findings

Anomalous decay rates are present for charged massive scalar fields.

A critical mass value causes the decay rate behavior to invert.

Critical charge parameters depend on the cosmological constant.

Abstract

The anomalous decay rate of the quasinormal modes occurs when the longest-lived modes are the ones with higher angular number. Such behaviour has been recently studied in different static spacetimes, for uncharged scalar and fermionic perturbations, being observed in both cases. In this work we consider the propagation of charged massive scalar fields in the background of Reissner-Nordstr\"om-de Sitter black holes and we mainly study the effect of the scalar field charge in the spectrum of quasinormal frequencies, as well as, its effect on the anomalous decay rate. Mainly, we show that the anomalous behaviour is present for massive charged scalar fields as well, and a critical value of scalar field mass exists, beyond which the behaviour is inverted. However, there is also a critical value of the parameter $qQ$ of the charge of the scalar field and of the charge of the black hole, which increases when the cosmological constant increases, and beyond the critical value the anomalous behaviour of the decay rate could be avoided for the fundamental mode.