Asymptotically conserved charges and 2-kink collision in quasi-integrable potential KdV models

Abstract

We study a particular deformation of the potential KdV model (pKdV) and construct the quasi-conservation laws by a direct method. The charge densities, differing from their integrable counterpart with homogeneous degree terms, exhibit mixed scale dimension terms. The modifications of the charges around the soliton interaction regions are examined by numerically simulating some representative anomalies. We show numerically the elastic scattering of two kinks for a wide range of values of the deformation parameters. It is discussed an anomaly cancellation mechanism to define an exact conservation law of the usual pKdV model, and a renormalization procedure is introduced for some divergent charges by subtructing the continuous linear background contribution. The KdV-type equations are quite ubiquitous in several areas of non-linear science, such as the study of General Relativity in $AdS_{3}$, Bose-Einstein condensates, superconductivity and fluid dynamics.