{ "id": "0709.2667", "version": "v2", "published": "2007-09-17T16:43:42.000Z", "updated": "2008-04-22T14:52:26.000Z", "title": "Cantor Spectrum for Schrödinger Operators with Potentials arising from Generalized Skew-shifts", "authors": [ "Artur Avila", "Jairo Bochi", "David Damanik" ], "comment": "Final version. To appear in Duke Mathematical Journal", "journal": "Duke Mathematical Journal, 146, no. 2 (2009), 253-280", "doi": "10.1215/00127094-2008-065", "categories": [ "math.DS", "math-ph", "math.MP", "math.SP" ], "abstract": "We consider continuous $SL(2,\\mathbb{R})$-cocycles over a strictly ergodic homeomorphism which fibers over an almost periodic dynamical system (generalized skew-shifts). We prove that any cocycle which is not uniformly hyperbolic can be approximated by one which is conjugate to an $SO(2,\\mathbb{R})$-cocycle. Using this, we show that if a cocycle's homotopy class does not display a certain obstruction to uniform hyperbolicity, then it can be $C^0$-perturbed to become uniformly hyperbolic. For cocycles arising from Schr\\\"odinger operators, the obstruction vanishes and we conclude that uniform hyperbolicity is dense, which implies that for a generic continuous potential, the spectrum of the corresponding Schr\\\"odinger operator is a Cantor set.", "revisions": [ { "version": "v2", "updated": "2008-04-22T14:52:26.000Z" } ], "analyses": { "keywords": [ "generalized skew-shifts", "schrödinger operators", "cantor spectrum", "potentials arising", "uniform hyperbolicity" ], "tags": [ "journal article" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2007arXiv0709.2667A" } } }