Bound states of discrete Schrödinger operators on one and two dimensional lattices
We study the spectral properties of discrete Schrödinger operator $$ \widehat H_μ=\widehat H_0 + μ\widehat{V},\qquad μ\ge0, $$ associated to a one-particle system in $d$-dimensional lattice $\mathbb{Z}^d, $ $d=1,2,$ where the non-perturbed operator $\hat H_0$ is a self-adjoint Laurent-Toeplitz-type operator generated by $\hat e:\mathbb{Z}^d\to\mathbb{C}$ and the potential $\hat V$ is the multiplication operator by $\hat v:\mathbb{Z}^d\to\mathbb{R}.$ Under certain regularity assumption on $\hat e$ and a decay assumption on $\hat v$, we establish the existence or non-existence and also the finiteness of eigenvalues of $\hat H_μ.$ Moreover, in the case of existence we study the asymptotics of eigenvalues of $\hat H_μ$ as $μ\searrow 0.$
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