The focusing energy-critical nonlinear Schrödinger equation in dimensions five and higher

We consider the focusing energy-critical nonlinear Schr\"odinger equation $iu_t+\Delta u = - |u|^{4\over{d-2}}u$ in dimensions $d\geq 5$. We prove that if a maximal-lifespan solution $u\colon \ I\times {\Bbb R}^d\to {\Bbb C}$ obeys $\sup_{t\in I}\|\nabla u(t)\|_2<\|\nabla W\|_2$, then it is global and scatters both forward and backward in time. Here $W$ denotes the ground state, which is a stationary solution of the equation. In particular, if a solution has both energy and kinetic energy less than those of the ground state $W$ at some point in time, then the solution is global and scatters. We also show that any solution that blows up with bounded kinetic energy must concentrate at least the kinetic energy of the ground state. Similar results were obtained by Kenig and Merle for spherically symmetric initial data and dimensions $d=3,4,5$.