Real Part Emergence in Purely Imaginary Quasinormal Modes in Perturbed de Sitter Braneworlds
This study investigates how adding small disturbances to a de Sitter brane causes purely imaginary quasinormal modes (QNMs) to gain a non-zero real part, potentially leading to oscillations in gravitational waves. The researchers used perturbations modeled by a double-kink function and found that the mode behavior is sensitive to perturbation strength and location.