TY - JOUR
T1 - Cantor spectrum for schrödinger operators with potentials arising from generalized skew-shifts
AU - Avila, Artur
AU - Bochi, Jairo
AU - Damanik, David
PY - 2009/2
Y1 - 2009/2
N2 - We consider continuous SL(2,R{double-struck})-cocycles over a strictly ergodic homeomorphism that fibers over an almost periodic dynamical system (generalized skew-shifts). We prove that any cocycle that is not uniformly hyperbolic can be approximated by one that is conjugate to an SO(2,R{double-struck})-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 C0-perturbed to become uniformly hyperbolic. For cocycles arising from Schrödinger 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 Schrödinger operator is a Cantor set.
AB - We consider continuous SL(2,R{double-struck})-cocycles over a strictly ergodic homeomorphism that fibers over an almost periodic dynamical system (generalized skew-shifts). We prove that any cocycle that is not uniformly hyperbolic can be approximated by one that is conjugate to an SO(2,R{double-struck})-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 C0-perturbed to become uniformly hyperbolic. For cocycles arising from Schrödinger 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 Schrödinger operator is a Cantor set.
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U2 - 10.1215/00127094-2008-065
DO - 10.1215/00127094-2008-065
M3 - Article
AN - SCOPUS:77954016470
SN - 0012-7094
VL - 146
SP - 253
EP - 280
JO - Duke Mathematical Journal
JF - Duke Mathematical Journal
IS - 2
ER -