{ "id": "1709.09200", "version": "v1", "published": "2017-09-26T18:09:53.000Z", "updated": "2017-09-26T18:09:53.000Z", "title": "Bounds on the Pure Point Spectrum of Lattice Schrödinger Operators", "authors": [ "Volker Bach", "Walter de Siqueira Pedra", "Saidakhmat Lakaev" ], "comment": "24 pages", "categories": [ "math-ph", "math.MP" ], "abstract": "In dimension $d\\geq 3$, a variational principle for the size of the pure point spectrum of (discrete) Schr\\\"odinger operators $H(\\mathfrak{e},V)$ on the hypercubic lattice $\\mathbb{Z}^{d}$, with dispersion relation $\\mathfrak{e}$ and potential $V$, is established. The dispersion relation $\\mathfrak{e}$ is assumed to be a Morse function and the potential $V(x)$ to decay faster than $|x|^{-2(d+3)}$, but not necessarily to be of definite sign. Our estimate on the size of the pure-point spectrum yields the absence of embedded and threshold eigenvalues of $H(\\mathfrak{e},V)$ for a class ot potentials of this kind. The proof of the variational principle is based on a limiting absorption principle combined with a positive commutator (Mourre) estimate, and a Virial theorem. A further observation of crucial importance for our argument is that, for any selfadjoint operator $B$ and positive number $\\lambda >0$, the number of negative eigenvalues of $\\lambda B$ is independent of $\\lambda$.", "revisions": [ { "version": "v1", "updated": "2017-09-26T18:09:53.000Z" } ], "analyses": { "keywords": [ "pure point spectrum", "lattice schrödinger operators", "variational principle", "dispersion relation", "class ot potentials" ], "note": { "typesetting": "TeX", "pages": 24, "language": "en", "license": "arXiv", "status": "editable" } } }