Agmon estimates for the difference of exact and approximate Dirichlet eigenfunctions for difference operators

Abstract

We analyze a general class of difference operators $H_\varepsilon = T_\varepsilon + V_\varepsilon$ on $\ell^2(\varepsilon\mathbb{Z}^d)$, where $V_\varepsilon$ is a multi-well potential and $\varepsilon$ is a small parameter. We construct approximate eigenfunctions in neighbourhoods of the different wells and give weighted $\ell^2$-estimates for the difference of these and the exact eigenfunctions of the associated Dirichlet-operators.