Nekhoroshev type stability for non-local semilinear Schr\"odinger equations

This paper investigates Nekhoroshev-type stability for solutions of ultra-differentiable regularity in Schrödinger equations with non-local nonlinear terms, employing the method of rational normal forms.

We establish the first rigorous results for logarithmic ultra-differentiable regularity in infinite-dimensional Hamiltonian systems without external parameters.

Under Gevrey class regularity assumptions, we achieve the stability times matching Bourgain's conjectured optimal stability time in \cite{B04}.

Furthermore, we introduce a novel global vector field norm adapted to the rational normal form framework.

This norm eliminate the need for degree tracking during the iteration process, thereby enabling a unified treatment of nonlinear terms.