Global Well-Posedness for the Fourth-Order Nonlinear Schrödinger Equation with Potential in the Energy-Critical Case

Abstract

We consider the defocusing fourth-order nonlinear Schrödinger equation with potential \[ i\partial_t u + Δ^2 u + Vu + λ|u|^{p-1}u = 0 \qquad (x \in \mathbb{R}^n,\ t \in \mathbb{R}), \] 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 Schrödinger equation. The proof relies on Strichartz estimates for fourth-order Schrödinger operators with potential, equivalence of Sobolev norms associated with $Δ^2+V$ and $Δ^2$, 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.