We investigate the role that quasinormal modes can play in kink–antikink collisions, via an example based on a deformation of the ϕ4 model. We find that narrow quasinormal modes can store energy during collision processes and later return it to the translational degrees of freedom. Quasinormal modes also decay, which leads to energy leakage, causing a closing of resonance windows and an increase of the critical velocity. We observe similar phenomena in an effective model, a small modification of the collective-coordinate approach to the ϕ4 model.
Dorey, P., & Romańczukiewicz, T. (2018). Resonant kink-antikink scattering through quasinormal modes. Physics Letters B, 779, 117-123. https://doi.org/10.1016/j.physletb.2018.02.003