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arXiv 1910.07720nlin.SI
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具有非零渐近边界条件的修正非线性Schröinger方程的Riemann-Hilbert方法

Riemann-Hilbert approach to the modified nonlinear Schröinger equation with non-vanishing asymptotic boundary conditions

Yiling Yang, Engui Fan

摘要:

提出了修正的非线性薛定谔(NLS)方程来描述Alfven波和飞秒光脉冲在非线性单模光纤中的非线性传输。本文给出了无穷远渐近边界为非零的修正NLS方程的逆散射变换。通过引入适当的双叶Riemann曲面,将原始谱参数$k$映射为单值参数$z$ .详细分析了修正NLS方程的拉克斯对的Jost解的渐近性态、解析性和对称性,以及谱矩阵.然后建立了一个与非零渐近边界条件问题相联系的矩阵Riemann-Hilbert(RH)问题,利用相应的重构公式得到了$N$ -孤子解.作为$N$ -孤子公式的一个例子,根据谱的不同分布,给出了两种单孤子解和三种双孤子解.这些解决方案的动力学特征的特点是在特定的情况下与四重离散特征值。结果表明,谱的分布和非零边界也影响孤子解的性质。最后,我们分析了我们的结果与零边界情况下的结果之间的差异。

英文摘要:

The modified nonlinear Schrödinger (NLS) equation was proposed to describe the nonlinear propagation of the Alfven waves and the femtosecond optical pulses in a nonlinear single-mode optical fiber. In this paper, the inverse scattering transform for the modified NLS equation with non-vanishing asymptotic boundary at infinity is presented. An appropriate two-sheeted Riemann surface is introduced to map the original spectral parameter $k$ into a single-valued parameter $z$. The asymptotic behaviors, analyticity and the symmetries of the Jost solutions of Lax pair for the modified NLS equation, as well as the spectral matrix are analyzed in details. Then a matrix Riemann-Hilbert (RH) problem associated with the problem of nonzero asymptotic boundary conditions is established, from which $N$-soliton solutions is obtained via the corresponding reconstruction formulae. As an illustrate examples of $N$-soliton formula, two kinds of one-soliton solutions and three kinds of two-soliton solutions are explicitly presented according to different distribution of the spectrum. The dynamical feature of those solutions are characterized in the particular case with a quartet of discrete eigenvalues. It is shown that distribution of the spectrum and non-vanishing boundary also affect feature of soliton solutions. Finally, we analyze the differences between our results and those on zero boundary case.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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