The Calogero--Moser Derivative Nonlinear Schr\"odinger Equation

TL;DR

This paper investigates the Calogero--Moser derivative nonlinear Schrödinger equation, establishing global well-posedness, classifying solitary waves, and analyzing multi-soliton solutions with energy cascade behavior.

Contribution

It introduces a Lax pair approach for the $L^2$-critical equation, proving well-posedness for certain initial data, and provides a detailed analysis of soliton solutions and their energy dynamics.

Findings

Global well-posedness for $s \\geq 1$ and sub-critical $L^2$ mass.

Classification of ground states and traveling solitary waves.

Multi-soliton solutions exhibit energy cascades with polynomial growth in Sobolev norms.

Abstract

We study the Calogero--Moser derivative NLS equation $$ i \partial_t u +\partial_{xx} u + (D+|D|)(|u|^2) u =0 $$ posed on the Hardy-Sobolev space $H^s_+(\mathbb{R})$ with suitable $s>0$. By using a Lax pair structure for this $L^2$-critical equation, we prove global well-posedness for $s \geq 1$ and initial data with sub-critical or critical $L^2$-mass $\| u_0 \|_{L^2}^2 \leq 2 \pi$. Moreover, we prove uniqueness of ground states and also classify all traveling solitary waves. Finally, we study in detail the class of multi-soliton solutions $u(t)$ and we prove that they exhibit energy cascades in the following strong sense such that $\|u(t)\|_{H^s} \sim_s |t|^{2s}$ as $t \to \pm \infty$ for every $s > 0$. \end{abstract}