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arXiv 2003.05011math.AP
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三次NLS和mKdV在$H^s(\mathbb R)$中的尖锐适定性

Sharp well-posedness for the cubic NLS and mKdV in $H^s(\mathbb R)$

Benjamin Harrop-Griffiths, Rowan Killip, Monica Visan

AI总结:

本文证明三次NLS和mKdV方程在$H^s(\mathbb R)$中对任意$s>-\frac12$全局适定,通过交换流方法、局部光滑效应和新的微观守恒律克服低正则性困难。

摘要:

我们证明三次非线性薛定谔方程(聚焦和散焦两种情形)在$H^s(\mathbb R)$中对任意正则性$s>-\frac12$都是全局适定的。对于$s\geq 0$,适定性早已为人所知,见文献[55],但此前对任何$s<0$都未曾得到。这里必然排除临界标度值$s=-\frac12$,因为已知瞬时范数膨胀会发生,见文献[11, 40, 48]。\n我们还(以平行方式)证明实值和复值修正Korteweg-de Vries方程在$H^s(\mathbb R)$中对任意$s>-\frac12$的适定性。此前达到的最佳正则性是$s\geq \frac14$,见文献[15, 24, 33, 39]。\n为了克服数据到解映射的一致连续性失效问题,我们采用文献[37]中引入的交换流方法。与我们在[37]中的论证形成鲜明对比的是,本文的一个基本要素是证明两个方程的局部光滑效应。尽管适定性具有非微扰性质,但导数的增益与底层线性方程一致。为了补偿光滑估计的局部性质,我们还证明了轨道的紧致性。局部光滑和紧致性的证明都依赖于我们发现的一个新的单参数强制微观守恒律族,该守恒律族在此低正则性下仍然有意义。

英文摘要:

We prove that the cubic nonlinear Schrödinger equation (both focusing and defocusing) is globally well-posed in $H^s(\mathbb R)$ for any regularity $s>-\frac12$. Well-posedness has long been known for $s\geq 0$, see [55], but not previously for any $s<0$. The scaling-critical value $s=-\frac12$ is necessarily excluded here, since instantaneous norm inflation is known to occur [11, 40, 48]. We also prove (in a parallel fashion) well-posedness of the real- and complex-valued modified Korteweg-de Vries equations in $H^s(\mathbb R)$ for any $s>-\frac12$. The best regularity achieved previously was $s\geq \frac14$; see [15, 24, 33, 39]. To overcome the failure of uniform continuity of the data-to-solution map, we employ the method of commuting flows introduced in [37]. In stark contrast with our arguments in [37], an essential ingredient in this paper is the demonstration of a local smoothing effect for both equations. Despite the non-perturbative nature of the well-posedness, the gain of derivatives matches that of the underlying linear equation. To compensate for the local nature of the smoothing estimates, we also demonstrate tightness of orbits. The proofs of both local smoothing and tightness rely on our discovery of a new one-parameter family of coercive microscopic conservation laws that remain meaningful at this low regularity.

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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