The weakly nonlinear Schrödinger equation in higher dimensions with quasi-periodic initial data

Abstract

In this paper, under the exponential/polynomial decay condition in Fourier space, we prove that the nonlinear solution to the quasi-periodic Cauchy problem for the weakly nonlinear Schrödinger equation in higher dimensions will asymptotically approach the associated linear solution within a specific time scale. The proof is based on a combinatorial analysis method presented through diagrams. Our results and methods apply to arbitrary space dimensions and general power-law nonlinearities of the form $\pm |u{|}^{2p}u$, where $1\le p\in N$.