Kink-antikink collisions in the phi^6 model

TL;DR

This paper investigates kink-antikink collisions in the phi^6 model, revealing resonant scattering phenomena without internal vibrational modes, challenging previous assumptions about multi-bounce resonances.

Contribution

It demonstrates that multi-bounce resonances can occur without internal vibrational modes, providing new insights into kink-antikink collision dynamics in non-integrable models.

Findings

Resonant scattering occurs without internal vibrational modes.

Two-bounce windows are linked to bound states in small oscillation spectra.

Counterexample to the belief that vibrational modes are necessary for multi-bounce resonances.

Abstract

We study kink-antikink collisions in the one-dimensional non-integrable scalar phi^6 model. Although the single-kink solutions for this model do not possess an internal vibrational mode, our simulations reveal a resonant scattering structure, thereby providing a counterexample to the standard belief that existence of such a mode is a necessary condition for multi-bounce resonances in general kink-antikink collisions. We investigate the two-bounce windows in detail, and present evidence that this structure is caused by existence of bound states in the spectrum of small oscillations about a combined kink-antikink configuration.