Resonance structures in kink-antikink scattering in a quantum vacuum

We investigate kink-antikink scattering in the λφ4 model in the presence of an additional scalar field, ψ, that is in its quantum vacuum and interacts with φ via a ζφ2ψ2 term where ζ is the coupling. The final state of such a scattering is either a bound state with eventual annihilation or a reflection of the kink-antikink pair. Without the ψ field, the outcome is known to depend fractally on the initial velocity of the kink-antikink pair. In the quantum vacuum of the ψ field, the fractal dependence gets modified and disappears above a critical interaction strength, ζ≈0.1.