Revisiting superradiant stability of Kerr-Newman black holes under a charged massive scalar

TL;DR

This paper analyzes the superradiant stability of Kerr-Newman black holes under charged massive scalar perturbations, deriving a new potential form that clarifies stability conditions.

Contribution

It introduces a new non-singular potential in the Schrödinger-type equation for better stability analysis of Kerr-Newman black holes.

Findings

Derived a new potential that is regular at the outer horizon.

Established a condition for superradiant stability.

Provided insights into black hole stability under scalar perturbations.

Abstract

We revisit the superradiant stability of Kerr-Newman black holes under a charged massive scalar perturbation. We obtain a newly suitable potential which is not singular at the outer horizon when a radial equation is expressed the Schr\"{o}dinger-type equation in terms of the tortoise coordinate. From the potential analysis, we find a condition for the superradiant stability of Kerr-Newman black holes.