We consider the defocusing fourth-order nonlinear Schr\"{ o}dinger equation with potential \[ i\partial_t u + \Delta^2 u + Vu + \lambda |u|^{ p-1}u = 0 \qquad (x \in \mathbb{ R}^n,\ t \in \mathbb{ R}), \] in dimensions $n \ge 5$. In the energy-critical case $p = \frac{ n+4}{ n-4}$, under suitable assumptions on a radial real-valued potential $V$, we prove global well-posedness for radial initial data in $H^2(\mathbb{ R}^n)$. We also show that every such solution scatters in $H^2$ to a free solution of the biharmonic Schr\"{ o}dinger equation. The proof relies on Strichartz estimates for fourth-order Schr\"{ o}dinger operators with potential, equivalence of Sobolev norms associated with $\Delta^2+V$ and $\Delta^2$, boundedness of wave operators, perturbative stability theory, and a Morawetz-type estimate adapted to the presence of a potential. This extends earlier results for the case without potential to a class of radial potentials.
Categories: math.AP