2019/09/06 by Geng, Jiansheng, Xue, Shuaishuai
#Dynamical Systems (math.DS) #FOS: Mathematics
paper · doi:10.48550/arxiv.1909.02681
We prove an infinite dimensional KAM theorem. As an application, we use the theorem to study the two-dimensional nonlinear Schrödinger equation iut-\triangle u +|u|2u+\frac∂f(x,u, u)∂ u=0, t∈\Bbb R, x∈\Bbb T2 with periodic boundary conditions, where the nonlinearity f(x,u, u)=∑j,l,j+l≥6ajl(x)uj ul, ajl=alj is a real analytic function in a neighborhood of the origin. We obtain for the equation a Whitney smooth family of small--amplitude quasi--periodic solutions which are partially hyperbolic.