Nongauge bright soliton of the nonlinear Schrodinger (NLS) equation and a family of generalized NLS equations

摘要

We present an approach to the bright soliton solution of the nonlinear Schrodinger (NLS) equation from the standpoint of introducing a constant potential term in the equation. We discuss a "nongauge" bright soliton for which both the envelope and the phase depend only on the traveling variable. We also construct a family of generalized NLS equations with solitonic sechp solutions in the traveling variable and find an exact equivalence with other nonlinear equations, such as the Korteveg-de Vries (KdV) and Benjamin-Bona-Mahony (BBM) equations when p = 2.