Random data Cauchy theory for the fourth order nonlinear Schr\"{o}dinger equation with cubic nonlinearity

TL;DR

This paper establishes almost sure local and global well-posedness, along with scattering results, for a fourth order nonlinear Schrödinger equation with derivative nonlinearity and random initial data in certain Sobolev spaces.

Contribution

It introduces a probabilistic approach to prove well-posedness and scattering for the equation below the scale critical regularity, expanding the understanding of such equations.

Findings

Almost sure local well-posedness in H^s for s > (d-5)/2 or (d-5)/6

Global well-posedness and scattering for small initial data

Lower regularity threshold below the scale critical regularity

Abstract

We consider the Cauchy problem for the fourth order nonlinear Schr\"{o}dinger equation with derivative nonlinearity $(i\partial _t + \Delta ^2) u= \pm \partial (|u|^2u)$ on $\mathbb{R} ^d$, $d \ge 3$, with random initial data, where $\partial$ is a first order derivative with respect to the spatial variable, for example a linear combination of $\frac{\partial}{\partial x_1} , \, \dots , \, \frac{\partial}{\partial x_d}$ or $|\nabla |= \mathcal{F}^{-1}[|\xi | \mathcal{F}]$. We prove that almost sure local in time well-posedness, small data global in time well-posedness and scattering hold in $H^s(\mathbb{R} ^d)$ with $\max ( \frac{d-5}{2}, \frac{d-5}{6}) < s$, whose lower bound is below the scale critical regularity $s_c= \frac{d-3}{2}$.