Collective Coordinate Model of Kink-Antikink Collisions in φ4 Theory

Abstract

The fractal velocity pattern in symmetric kink-antikink collisions in φ4 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.