Parity breaking reshapes black hole spectral dynamics

TL;DR

This paper introduces a mechanism to detect parity symmetry breaking in black holes by analyzing spectral instabilities of quasinormal modes, revealing unique phenomena in modified gravity theories like dynamical Chern-Simons gravity.

Contribution

It demonstrates how environmental perturbations can amplify subtle symmetry-breaking effects into observable gravitational wave signatures in black hole spectra.

Findings

Topological reconnections of mode branches in spectral spectra

Counterintuitive stabilization of modes delaying transitions

Scalar mode dominance at intermediate coupling strengths

Abstract

We propose a dynamical amplification mechanism for detecting symmetry breaking in black holes through environmentally driven spectral instabilities of quasinormal modes. Focusing on dynamical Chern-Simons gravity as a paradigm for parity violation, we perturb the Schwarzschild background with a localized potential bump. Our analysis reveals three distinctive phenomena absent in general relativity: 1) topological reconnections of mode branches, 2) counterintuitive mode stabilization that delays overtaking transitions, and 3) scalar mode dominance emerging at intermediate coupling strengths. These dynamical features amplify weak static splittings into observable signatures, establishing a connection between gravitational symmetry breaking and non-Hermitian spectral physics. Our framework provides new pathways for testing modified gravity theories through gravitational wave observations.