A note about a new class of two-kinks

TL;DR

This paper introduces a new class of two-kinks in a modified $^4$ model, revealing complex collision dynamics and fractal structures due to additional internal modes.

Contribution

It constructs a novel two-kink solution with an extra parameter and analyzes its internal modes and collision behavior, highlighting new nonlinear energy exchange phenomena.

Findings

Two-kinks possess two discrete internal modes besides the zero mode.

Collision dynamics exhibit fractal structures indicating complex energy exchange.

Additional internal modes influence the outcome of kink-antikink interactions.

Abstract

We present a model of two-kinks resulting from an explicit composition of two standards kinks of the $\phi^4$ model based on the procedure of Ref. \cite{uchiyama}. The two-kinks have an additional parameter accounting for the separation of the standard kinks of $\phi^4$ model. We have shown that the two-kinks have two discrete internal modes besides the zeroth mode and the continuous spectrum. This new feature signalizes that the head-on collision a two-kinks/two-antikinks pair exhibits a rich and complex behavior due to the additional channel from which the energy of the system can be stored. We have exhibited the fractal structure associated with the main configurations after the collision. We have inferred the fractality as the imprint of the nonlinear exchange of energy into the two discrete internal modes.