Soliton-like behaviour in non-integrable systems

We present a general scheme for constructing robust excitations (soliton-like) in non-integrable multicomponent systems. By robust, we mean localised that propagate with almost constant velocity and which interact cleanly little to no radiation. achieve this via reduction of these complex systems more familiar effective chiral field-theories using perturbation techniques the Fredholm alternative. As specific platform, consider generalised Nonlinear Schr\"{o}dinger Equations (MNLS) arbitrary interaction coefficients. This system reduces uncoupled Korteweg-de Vries (KdV) equations, one each sound speed system. then enables us exploit multi-soliton solutions KdV equation turn leads construction soliton-like profiles original demonstrate powerful technique coherent evolution minimal radiative loss These constructed objects bear remarkably close resemblance true solitons integrable models. Although use ubiquitous MNLS as our findings are major step forward towards generic continuum