Comment on "Specific sine-Gordon soliton dynamics in the presence of external driving forces"

Abstract

It is shown that the results presented by Reinisch and Fernandez have an alternative interpretation where the soliton does behave as a Newtonian particle. The key features required for this alternative interpretation are (i) properly defining where the center of the soliton is, and (ii) expanding the solution so as to avoid any secular terms. When these two objectives are achieved, then the center of the soliton is found to satisfy Newton's equation of motion for a point particle.