Collective Coordinate Model of Kink-Antikink Collisions in φ4 Theory

The fractal velocity pattern in symmetric kink-antikink collisions in phi(4) theory is shown to emerge from a dynamical model with two effective moduli: the kink-antikink separation and the internal shape mode amplitude. The shape mode usefully approximates Lorentz contractions of the kink and antikink, and the previously problematic null vector in the shape mode amplitude at zero separation is regularized.

Automated summary

The study reveals that the fractal velocity pattern in symmetric kink-antikink collisions can be explained by a dynamical model with two effective moduli. The shape mode is useful for approximating Lorentz contractions of the kink and antikink during collisions, and the problematic null vector in the shape mode amplitude at zero separation has been successfully regularized.