Resonance structures in kink-antikink collisions in a deformed sine-Gordon model

TL;DR

This paper investigates kink-antikink collisions in a deformed sine-Gordon model, revealing complex behaviors like resonance windows, integrability breaking, and the influence of false vacua and kink modes, supported by numerical and analytical analysis.

Contribution

It introduces a model interpolating between sine-Gordon, phi^4, and phi^6 theories, uncovering new collision phenomena and resonance structures not previously observed.

Findings

Identification of resonance windows with irregular patterns

Discovery of new window types near the phi^6-like regime

Role of false vacua and kink modes in collision dynamics

Abstract

We study kink-antikink collisions in a model which interpolates smoothly between the completely integrable sine-Gordon theory, the $\phi^4$ model, and a $\phi^6$-like model with three degenerate vacua. We find a rich variety of behaviours, including integrability breaking, resonance windows with increasingly irregular patterns, and new types of windows near the $\phi^6$-like regime. False vacua, extra kink modes and kink fragmentation play important roles in the explanations of these phenomena. Our numerical studies are backed up by detailed analytical considerations.