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arXiv 2404.09892math.NAcs.NA
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Nehari流形优化及其在求解半线性椭圆型偏微分方程不稳定解中的应用

Nehari manifold optimization and its application for finding unstable solutions of semilinear elliptic PDEs

Zhaoxing Chen, Wei Liu, Ziqing Xie, Wenfan Yi

AI总结:

提出Nehari流形优化方法求解Hilbert空间中泛函的1-鞍点,用于计算半线性椭圆PDE的不稳定基态解,并数值发现Hénon方程对称破缺临界值。

摘要:

本文提出了一种Nehari流形优化方法(NMOM),用于在Hilbert空间中寻找一般非线性泛函的1-鞍点,即Morse指标等于1的鞍点。实际上,该方法基于变分刻画:该泛函的1-鞍点是同一泛函限制在相关Nehari流形上的局部极小值点。该框架包含两个重要组成部分:一是回缩映射,使迭代点始终位于Nehari流形上;二是切向搜索方向,配合适当的步长搜索规则以减小泛函值。特别地,通过一些关键的分析技术(包括弱收敛方法),严格建立了全局收敛性,这些技术克服了无限维设置中的困难。在实践中,结合易于实现的Nehari回缩和负黎曼梯度方向,NMOM成功应用于计算一类典型半线性椭圆型偏微分方程的不稳定基态解,如稳态非线性薛定谔方程和Hénon方程。特别地,本文在1维和2维中数值探索了Hénon方程基态解的对称破缺现象,并报告了关于对称破缺临界值的有趣数值发现。

英文摘要:

A Nehari manifold optimization method (NMOM) is introduced for finding 1-saddles, i.e., saddle points with the Morse index equal to one, of a generic nonlinear functional in Hilbert spaces. Actually, it is based on the variational characterization that 1-saddles of this functional are local minimizers of the same functional restricted on the associated Nehari manifold. The framework contains two important ingredients: one is the retraction mapping to make the iterative points always lie on the Nehari manifold; the other is the tangential search direction to decrease the functional with suitable step-size search rules. Particularly, the global convergence is rigorously established by virtue of some crucial analysis techniques (including a weak convergence method) that overcome difficulties in the infinite-dimensional setting. In practice, combining with an easy-to-implement Nehari retraction and the negative Riemannian gradient direction, the NMOM is successfully applied to compute the unstable ground-state solutions of a class of typical semilinear elliptic PDEs, such as the stationary nonlinear Schrödinger equation and the Hénon equation. In particular, the symmetry-breaking phenomenon of the ground states of the Hénon equation is explored numerically in 1D and 2D with interesting numerical findings on the critical value of the symmetry-breaking reported.

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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