Resolvent bounds for repulsive potentials
Andrés Larraín-Hubach, Yulong Li, Jacob Shapiro, Joseph Tiller
TL;DR
The paper proves weighted limiting absorption (resolvent) bounds for the semiclassical Schrödinger operator $P(h) = -h^2 \Delta + V(x)$ in dimensions $n \ge 3$ with nonnegative, repulsive potentials that may have a singularity at the origin. Using a spherical energy method and careful weighted estimates, it derives nontrapping and low-frequency resolvent bounds in weighted $L^2$ spaces, valid for $s,s_1,s_2>1/2$ with $s_1+s_2>2$, and extends known one-dimensional results to higher dimensions including singularities like $r^{-1}$. These resolvent bounds feed into norm bounds for weighted Helmholtz resolvents and their $\lambda$-derivatives, which, via Fourier analysis and Duhamel's formula, yield time decay of the weighted energy for the associated wave equation with a short-range repulsive potential and compactly supported initial data. The results provide a rigorous link between low-energy resolvent behavior and long-time decay, with implications for dispersive and scattering phenomena in quantum mechanics and wave propagation.
Abstract
We prove limiting absorption resolvent bounds for the semiclassical Schrödinger operator with a repulsive potential in dimension $n\ge 3$, which may have a singularity at the origin. As an application, we obtain time decay for the weighted energy of the solution to the associated wave equation with a short range repulsive potential and compactly supported initial data.
