Long-time asymptotics of the coupled nonlinear Schödinger equation in a weighted Sobolev space

Fuente: arXiv
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Main Authors: Huang, Yubin, Ling, Liming, Zhang, Xiaoen
Format: Preprint
Published: 2025
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author Huang, Yubin
Ling, Liming
Zhang, Xiaoen
author_facet Huang, Yubin
Ling, Liming
Zhang, Xiaoen
contents We study the Cauchy problem for the focusing coupled nonlinear Schrödinger (CNLS) equation with initial data $\mathbf{q}_0$ lying in the weighted Sobolev space and the scattering data having $n$ simple zeros. Based on the corresponding $3\times3$ matrix spectral problem, we deduce the Riemann-Hilbert problem (RHP) for CNLS equation through inverse scattering transform. We remove discrete spectrum of initial RHP using Darboux transformations. By applying the nonlinear steepest-descent method for RHP introduced by Deift and Zhou, we compute the long-time asymptotic expansion of the solution $\mathbf{q}(x,t)$ to an (optimal) residual error of order $\mathcal{O}\left(t^{-3 / 4+1/(2p)}\right)$ where $2\le p<\infty$. The leading order term in this expansion is a multi-soliton whose parameters are modulated by soliton-soliton and soliton-radiation interactions. Our work strengthens and extends the earlier work regarding long-time asymptotics for solutions of the nonlinear Schrödinger equation with a delta potential and even initial data by Deift and Park.
format Preprint
id arxiv_https___arxiv_org_abs_2504_21315
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Long-time asymptotics of the coupled nonlinear Schödinger equation in a weighted Sobolev space
Huang, Yubin
Ling, Liming
Zhang, Xiaoen
Exactly Solvable and Integrable Systems
We study the Cauchy problem for the focusing coupled nonlinear Schrödinger (CNLS) equation with initial data $\mathbf{q}_0$ lying in the weighted Sobolev space and the scattering data having $n$ simple zeros. Based on the corresponding $3\times3$ matrix spectral problem, we deduce the Riemann-Hilbert problem (RHP) for CNLS equation through inverse scattering transform. We remove discrete spectrum of initial RHP using Darboux transformations. By applying the nonlinear steepest-descent method for RHP introduced by Deift and Zhou, we compute the long-time asymptotic expansion of the solution $\mathbf{q}(x,t)$ to an (optimal) residual error of order $\mathcal{O}\left(t^{-3 / 4+1/(2p)}\right)$ where $2\le p<\infty$. The leading order term in this expansion is a multi-soliton whose parameters are modulated by soliton-soliton and soliton-radiation interactions. Our work strengthens and extends the earlier work regarding long-time asymptotics for solutions of the nonlinear Schrödinger equation with a delta potential and even initial data by Deift and Park.
title Long-time asymptotics of the coupled nonlinear Schödinger equation in a weighted Sobolev space
topic Exactly Solvable and Integrable Systems
url https://arxiv.org/abs/2504.21315