The defocusing Calogero--Moser derivative nonlinear Schr{ö}dinger equation with a nonvanishing condition at infinity
Xi Chen
TL;DR
This work analyzes the defocusing Calogero-Moser derivative NLS on the real line with nonvanishing boundary at infinity. It develops a functional framework based on the energy space $E$ and its chiral subspace $E_+$, proves global well-posedness in $E$, and establishes uniform long-time bounds via a Lax-pair structure and two conservation laws. A key contribution is an explicit Poisson-type formula for chiral solutions in $E_+$, extending known explicit formulas from $H_+^s$ to the energy setting. The combination of local well-posedness, conserved quantities, and the explicit solution representation provides tools to study long-time dynamics, potential zero-dispersion limits, and traveling waves within this nonzero-background regime.
Abstract
We consider the defocusing Calogero--Moser derivative nonlinear Schr{ö}dinger equation\begin{align*}i \partial_{t} u+\partial_{x}^2 u-2ΠD\left(|u|^{2}\right)u=0, \quad (t,x ) \in \mathbb{R} \times \mathbb{R}\end{align*}posed on $E := \left\{u \in L^{\infty}(\mathbb{R}): u' \in L^{2}(\mathbb{R}), u'' \in L^{2}(\mathbb{R}), |u|^{2}-1 \in L^{2}(\mathbb{R})\right\}$. We prove the global well-posedness of this equation in $E$. Moreover, we give an explicit formula for the chiral solution to this equation.
