Nonlinear Schrödinger equation with Ornstein-Uhlenbeck operator
Xueying Yu, Haitian Yue, Zehua Zhao
TL;DR
This work introduces nonlinear Schrödinger equations with an Ornstein-Uhlenbeck drift acting as a confining direction, analyzed in two formulations: divergence-form OU and non-divergence-form OU. The authors establish Strichartz estimates and Gaussian-weighted Morawetz inequalities in this mixed-geometry setting, proving a virial-type blow-up result for the divergence form and global well-posedness with small-data scattering for the non-divergence form in key 2D and 3D regimes. The analysis leverages spectral decompositions via OU eigenfunctions and Keel–Tao machinery, capturing waveguide-like dispersive behavior in a non-product geometry and revealing how drift confinement mimics compactness. The results provide foundational tools for NLS under soft confinement and open avenues for stochastic extensions, broader confinement mechanisms, and long-time dynamics in mixed-geometry dispersive PDEs.
Abstract
In this work, we introduce and study nonlinear Schrödinger equations (NLS) with anisotropic dispersion, where the standard Laplacian acts on the Euclidean variable \(x \in \mathbb{R}^d\), and an Ornstein-Uhlenbeck ($\mathcal{OU}$) operator governs the confined direction \(α\in \mathbb{R}\). We consider models with two natural variants of $\mathcal{OU}$-induced confinement: (Model Div) based on the divergence form \(\nabla_α\cdot (e^{-\frac{α^2}{2}} \nabla_α)\), and (Model Non-Div) based on the non-divergence form \(Δ_α- α\cdot \nabla_α\). For both models, we establish the Strichartz estimates and Gaussian-weighted Morawetz estimates. In addition, for (Model Div), we prove a virial-type finite-time blow-up result; for (Model Non-Div), we establish global well-posedness and small data scattering in the 2D quintic and 3D cubic cases. The primary motivation of this work is to capture waveguide-type dispersive behavior in a Euclidean setting. To the best of our knowledge, this is the first rigorous analysis of NLS with $\mathcal{OU}$ operators in both divergence and non-divergence forms.
