Commutator Estimates and Quantitative Local Weyl's Law for Schrödinger Operators with Non-Smooth Potentials
Esteban Cárdenas, Laurent Lafleche
TL;DR
This work develops sharp commutator estimates for semiclassical Schrödinger operators with non-smooth potentials and uses them to derive quantitative local and phase-space Weyl laws for both non-interacting and interacting (Hartree) particle systems. The authors establish uniform-in-$\hbar$ Schatten-norm bounds for commutators $[x,\boldsymbol{\gamma}]$ and $[\hbar\nabla,\boldsymbol{\gamma}]$, relate these to regularity of $f_{\boldsymbol{\gamma}}$ and $\varrho_{\boldsymbol{\gamma}}$, and prove Besov-type phase-space bounds and Agmon-type decay. They extend the linear theory to the Hartree nonlinear setting, obtaining nonlinear commutator bounds that depend on the singularity of the interaction $K(x)=\kappa|x|^{-a}$, including the Coulomb case ($a=1$) with logarithmic corrections. The results yield precise rates of convergence for densities and Wigner functions to Thomas–Fermi limits, and provide robust tools for semiclassical analysis of many-body quantum systems with non-smooth interactions. Collectively, these results strengthen the quantum-classical correspondence in non-smooth regimes and have potential implications for effective mean-field descriptions of interacting fermions, especially in Coulombic environments.
Abstract
We analyze semi-classical Schrödinger operators with potentials of class $C^{1,1/2}$ and establish commutator estimates for the associated projection operators in Schatten norms. These are then applied to prove quantitative versions of the local and phase space Weyl laws in $L^p$ spaces. We study both non-interacting, and interacting particle systems. In particular, we are able to treat the case of the minimizers of the Hartree energy in the case of repulsive singular pair interactions such as the Coulomb potential.
