The Existence of full dimensional tori for d-dimensional Nonlinear Schr$\ddot{\mbox{O}}$dinger equation

TL;DR

This paper proves the existence of full dimensional invariant tori for a class of d-dimensional nonlinear Schrödinger equations with convolution potential, confirming a conjecture by Bourgain and revealing slower decay rates of the tori's radius.

Contribution

It establishes the existence of full dimensional tori with slower decay rates in the radius for d-dimensional NLS equations, confirming Bourgain's conjecture.

Findings

Existence of full dimensional tori for d-dimensional NLS with convolution potential.

Radius of invariant tori decays as e^{-r ln^{σ}(n)} with σ>2.

Confirms Bourgain's conjecture from 2005.

Abstract

In this paper, we prove the existence of full dimensional tori for $d$-dimensional nonlinear Schr$\ddot{\mbox{o}}$dinger equation with periodic boundary conditions \begin{equation*}\label{L1} \sqrt{-1}u_{t}+\Delta u+V*u\pm\epsilon |u|^2u=0,\hspace{12pt}x\in\mathbb{T}^d,\quad d\geq 1, \end{equation*} where $V*$ is the convolution potential. Here the radius of the invariant torus satisfies a slower decay, i.e. \begin{equation*}\label{031601} I_{\textbf n}\sim e^{-r\ln^{\sigma}\left\|\textbf n\right\|},\qquad \mbox{as}\ \left\|\textbf n\right\|\rightarrow\infty, \end{equation*}for any $\sigma>2$ and $r\geq 1$. This result confirms a conjecture by Bourgain [J. Funct. Anal. 229 (2005), no. 1, 62-94].