Exact solitary wave solutions for a coupled gKdV-Schrodinger system by a new ODE reduction method

TL;DR

This paper introduces a systematic new method to find exact solitary wave solutions for a coupled gKdV-Schrodinger system, revealing 22 solution families for various nonlinearities, including previously unknown solutions for p>1.

Contribution

A novel ODE reduction technique that systematically derives all polynomial solutions for coupled nonlinear dispersive wave equations, expanding known solution families.

Findings

22 solution families for p=1,2,3,4

New solutions for p>1 not previously known

Features include bright/dark peaks and kink profiles

Abstract

A new method is developed for finding exact solitary wave solutions of a generalized Korteweg-de Vries equation with p-power nonlinearity coupled to a linear Schr\"odinger equation arising in many different physical applications. This method yields 22 solution families, with p=1,2,3,4. No solutions for p>1 were known previously in the literature. For p=1, four of the solution families contain bright/dark Davydov solitons of the 1st and 2nd kind, obtained in recent work by basic ansatze applied to the ODE system for travelling waves. All of the new solution families have interesting features, including bright/dark peaks with (up to) p symmetric pairs of side peaks in the amplitude and a kink profile for the nonlinear part in the phase. The present method is fully systematic and involves several novel steps which reduce the travelling wave ODE system to a single nonlinear base ODE for which all polynomial solutions are found by symbolic computation. It is applicable more generally to other coupled nonlinear dispersive wave equations as well as to nonlinear ODE systems of generalized H\'enon-Heiles form.