Eur.Phys.J.C, 82, 546 (2022)
Extremal charged black holes and superradiantly unstable quasinormal modes
Zhan-Feng Mai1, Run-Qiu Yang1 and Hong Lü1
1 Center for Joint Quantum Studies, Department of Physics, School of Science, Tianjin University, Tianjin 300350, China.
* mrhonglu@gmail.com
Abstract
It was recently shown that the extremal charged black holes in STU supergravity su er from superradiant instability owing to the existence of the unstable (low-frequency) qua sibound states associated with a charged massive scalar eld. In this paper, we show numerically that for some charge con gurations, these black holes can also excite the (higher-frequency) superradiantly unstable quasinormal modes. We find empirically that the unstable modes are closely related to having a volcano-shaped effective potential in the Schrodinger-like wave equation.
