Spectral Butterfly Effect and Resilient Ringdown in Thick Braneworlds
Deformations of a thick braneworld's effective potential cause dramatic shifts in its quasinormal mode spectrum, creating a 'spectral butterfly effect.' While spectral features are fragile and rearrange easily, the prompt ringdown remains controlled by the original barrier. This coexistence suggests that while the standard gravitational-wave fingerprint is sensitive to small changes, it also reveals a resilient pattern of extra-dimensional physics.