Exponential Decays of Steklov Eigenfunctions for the Magnetic Laplacian
Zhongwei Shen
TL;DR
This work analyzes the exponential decay of Steklov-type eigenfunctions for the magnetic Dirichlet-to-Neumann map associated with the magnetic Laplacian $H(β\mathbf{A})=(D+β\mathbf{A})^2$ on a bounded Lipschitz domain. By constructing an Agmon distance $d_β$ weighted by the magnetic field and exploiting the finite-type condition on $\mathbf{B}$, the authors establish $L^2$ and pointwise decay estimates for eigenfunctions when the field strength $β$ is large. The main finding is that ground-state eigenfunctions decay exponentially away from the boundary subset where $\mathbf{B}$ vanishes to the maximal order, with quantitative bounds expressed through the magnetic wells $W_β(t)$ and the distance $d_β$. The results also cover different vanishing scenarios, including non-vanishing and higher-order vanishing of the magnetic field, and provide explicit implications for the localization near boundary magnetic wells.
Abstract
Consider the Dirichlet-to-Neumann map $Λ_β$ associated with the Schrödinger operator $(D+β\A)^2$ with a magnetic potential in a bounded Lipschitz domain $Ω$, where $β>1$ is the field strength parameter. Assume that the magnetic field $\B=\nabla \times \A$ is of finite type. We show that if $β>β_0$, the ground state for $Λ_β$ decays exponentially away from a neighborhood of the subset of $\partialΩ$, on which $\B$ vanishes to the maximal order.
