“Listening to Regular Black Holes: QNMs and Ringdown in Two Scalar Coupling Models”
Abstract
Quasi-normal modes (QNMs) play a central role in black hole physics, as they govern the characteristic “ringdown” phase of gravitational wave signals and provide a powerful tool to test the nature of compact objects beyond general relativity. In this talk, we investigate the QNMs and ringdown behavior of regular black holes in two distinct coupling scenarios for a scalar field. In the first model, the scalar field is non-minimally coupled to the Ricci scalar, which modifies the effective potential and influences the oscillation spectrum. In the second model, we consider the derivative coupling of the scalar field to the Einstein tensor, a higher-order interaction that significantly alters the perturbation dynamics near the horizon. By analyzing the corresponding quasi-normal spectra, we highlight the differences in stability, damping times, and late-time ringing between the two couplings. These findings shed light on how field–geometry interactions affect gravitational wave signatures of regular black holes and may provide potential observational imprints to distinguish among modified gravity models.