Superradiance and stability of rotating charged black holes in T-duality

TL;DR

This paper explores how electric charge and quantum deformation parameters influence the shadow, quasinormal modes, superradiance, and stability of rotating charged black holes under T-duality, revealing new phenomenological behaviors and stability regimes.

Contribution

It provides a comprehensive analysis of the effects of charge and quantum deformation on black hole shadows, QNMs, superradiance, and stability in T-duality, highlighting novel behaviors and extended stability regimes.

Findings

Shadow radius decreases with increasing electric charge.

Shadow radius initially increases then decreases with quantum deformed parameter $l_0$.

Superradiance amplification peaks and then diminishes with parameters Q and $l_0$.

Abstract

We investigate the shadow images, the relation between Quasinormal Modes (QNMs) and the shadow radius, and the superradiance effect observed in the context of a rotating charged black hole under T-duality. Our investigation places particular emphasis on two key parameters: the electric charge denoted as $Q$ and the quantum deformed parameter represented by the zero-point length, $l_0$. Our findings reveal a distinct pattern: as the electric charge increases, the shadow radius experiences a consistent decrease. Intriguingly, when considering the quantum deformed parameter, we find a noteworthy phenomenona reflecting point. Specifically, we illustrate that the shadow radius initially increases with an increase in $l_0$ and subsequently decreases. Further analysis involves the computation of eikonal equatorial and polar QNMs, where a similar reflecting point emerges upon varying $l_0$. This establishes the inverse correlation between QNMs and shadow radius within our research framework. Our investigation into the effects of Q and $l_0$ on superradiance reveals that the amplification factor initially increases with $Q$ and $l_0$ and then starts decreasing. Moreover, the rotating black holes in T-duality allows superradiance scattering for a wider range of frequency than Kerr black holes, making black holes in T-duality brighter than the Kerr black holes. We also delve into the stability of the combined system of the rotating black hole and scalar field with the help of black hole bomb mechanism. It provides a window to observe the impact of parameters Q and $l_0$ on the stability. It shows that the combined system is stable for a wider regime for the Kerr black hole.