Global well-posedness and scattering for the defocusing energy-critical nonlinear Schrödinger equation in $\R^{1+4}$
E. Ryckman, M. Visan
TL;DR
This work establishes global well-posedness and scattering for the defocusing cubic energy-critical NLS in ${\mathbb R}^{1+4}$ for finite-energy data. It refines the concentration-compactness/rigidity approach of CKSTT by providing a simpler frequency-localized interaction Morawetz inequality, yielding a superior bound on the critical spacetime norm $\|u\|_{L^6_{t,x}}$. A key part of the argument is ruling out energy evacuation to high frequencies via a detailed frequency/localization analysis and perturbation theory, culminating in a contradiction that proves global control and scattering. The result also furnishes a tower-type bound on the $L^6_{t,x}$ norm, highlighting the quantitative complexity of the energy-critical problem while guaranteeing asymptotic completeness and uniform regularity.
Abstract
We obtain global well-posedness, scattering, uniform regularity, and global $L^6_{t,x}$ spacetime bounds for energy-space solutions to the defocusing energy-critical nonlinear Schr\"odinger equation in $\R\times\R^4$. Our arguments closely follow those of Colliander-Keel-Staffilani-Takaoka-Tao, though our derivation of the frequency-localized interaction Morawetz estimate is somewhat simpler. As a consequence, our method yields a better bound on the $L^6_{t,x}$-norm.
