Low Energy Skyrmion-Skyrmion Scattering

TL;DR

This paper investigates low-energy Skyrmion scattering by reducing the system to a finite-dimensional manifold, revealing that at large separation, the dynamics resemble a Kepler problem due to the dominant metric-induced interaction.

Contribution

It introduces a finite-dimensional manifold approach for Skyrmion scattering and demonstrates that the low-energy dynamics reduce to a geodesic problem, with the interaction dominated by the induced metric.

Findings

Interaction is mainly from the induced metric, not the static potential.

At large separation, the Skyrmion scattering reduces to a Kepler problem.

The approach simplifies the complex Skyrmion dynamics to a manageable finite-dimensional model.

Abstract

We study the scattering of two Skyrmions at low energy and large separation. We use the method proposed by Manton for truncating the degrees of freedom of the system from infinite to a manageable finite number. This corresponds to identifying the manifold consisting of the union of the low energy critical points of the potential along with the gradient flow curves joining these together and by positing that the dynamics is restricted here. The kinetic energy provides an induced metric on this manifold while restricting the full potential energy to the manifold defines a potential. The low energy dynamics is now constrained to these finite number of degrees of freedom. For large separation of the two Skyrmions the manifold is parametrised by the variables of the product ansatz. We find the interaction between two Skyrmions coming from the induced metric, which was independently found by Schroers. We find that the static potential is actually negligible in comparison to this interaction. Thus to lowest order, at large separation, the dynamics reduces to geodesic motion on the manifold. We consider the scattering to first order in the interaction using the perturbative method of Lagrange and find that the dynamics in the no spin or charge exchange sector reduces to the Kepler problem.