Parity breaking reshapes black hole spectral dynamics

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.