{ "id": "1501.07876", "version": "v1", "published": "2015-01-30T18:39:37.000Z", "updated": "2015-01-30T18:39:37.000Z", "title": "Commutation Relations for Unitary Operators II", "authors": [ "M. A. Astaburuaga", "O. Bourget", "V. H. Cortés" ], "categories": [ "math.FA" ], "abstract": "Let $f$ be a regular non-constant symbol defined on the $d$-dimensional torus ${\\mathbb T}^d$ with values on the unit circle. Denote respectively by $\\kappa$ and $L$, its set of critical points and the associated Laurent operator on $l^2({\\mathbb Z}^d)$. Let $U$ be a suitable unitary local perturbation of $L$. We show that the operator $U$ has finite point spectrum and no singular continuous component away from the set $f(\\kappa)$. We apply these results and provide a new approach to analyze the spectral properties of GGT matrices with asymptotically constant Verblunsky coefficients. The proofs are based on positive commutator techniques. We also obtain some propagation estimates.", "revisions": [ { "version": "v1", "updated": "2015-01-30T18:39:37.000Z" } ], "analyses": { "keywords": [ "unitary operators", "commutation relations", "asymptotically constant verblunsky coefficients", "singular continuous component away", "finite point spectrum" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2015arXiv150107876A" } } }