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Related papers: Almost reducibility and absolute continuity I

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We develop a new KAM scheme that applies to SL(2,R) cocycles with one frequency, irrespective of any Diophantine condition on the base dynamics. It gives a generalization of Dinaburg-Sinai's Theorem to arbitrary frequencies: under a…

Dynamical Systems · Mathematics 2010-01-19 Artur Avila , Bassam Fayad , Raphael Krikorian

We prove that the size of the spectral gaps of weakly coupled quasi-periodic Schr\"odinger operators with Liouville frequencies decays exponentially. As an application, we obtain the homogeneity of the spectrum.

Spectral Theory · Mathematics 2021-11-03 Wencai Liu , Yunfeng Shi

We consider continuous $\mathrm{SL}(2,\mathbb{R})$ valued cocycles over general dynamical systems and discuss a variety of uniformity notions. In particular, we provide a description of uniform one-parameter families of continuous…

Dynamical Systems · Mathematics 2022-07-26 David Damanik , Daniel Lenz

We study the reducibility of a Linear Schr\"odinger equation subject to a small unbounded almost-periodic perturbation which is analytic in time and space. Under appropriate assumptions on the smallness, analiticity and on the frequency of…

Analysis of PDEs · Mathematics 2019-10-29 Riccardo Montalto , Michela Procesi

For quasiperiodic Schr\"odinger operators with one-frequency analytic potentials, from dynamical systems side, it has been proved that the corresponding quasiperiodic Schr\"odinger cocycle is either rotations reducible or has positive…

Dynamical Systems · Mathematics 2021-01-28 Hongyu Cheng , Lingrui Ge , Jiangong You , Qi Zhou

We show that some spectral properties of the almost Mathieu operator with frequency well approximated by rationals can be as poor as at all possible in the class of all one-dimensional discrete Schroedinger operators. For the class of…

Mathematical Physics · Physics 2023-03-31 Artur Avila , Yoram Last , Mira Shamis , Qi Zhou

In this paper, we prove that any analytic quasi-periodic cocycle close to constant is the Poincar\'{e} map of an analytic quasi-periodic linear system close to constant. With this local embedding theorem, we get fruitful new results. We…

Dynamical Systems · Mathematics 2015-06-04 Jiangong You , Qi Zhou

We show that a large class of limit-periodic Schr\"odinger operators has purely absolutely continuous spectrum in arbitrary dimensions. This result was previously known only in dimension one. The proof proceeds through the non-perturbative…

Spectral Theory · Mathematics 2013-04-11 Helge Krueger

We establish the absolute continuity of the integrated density of states (IDS) for quasi-periodic Schr\"odinger operators with a large trigonometric potential and Diophantine frequency. This partially solves Eliasson's open problem in 2002.…

Spectral Theory · Mathematics 2023-05-09 Jing Wang , Xu Xu , Jiangong You , Qi Zhou

We prove non-perturbative Anderson localization and almost localization for a family of quasi-periodic operators on the strip. As an application we establish Avila's almost reducibility conjecture for Schr\"odinger operators with…

Mathematical Physics · Physics 2023-07-04 Rui Han , Wilhelm Schlag

We continue our study of the local theory for quasiperiodic cocycles in $\mathbb{T} ^{d} \times G$, where $G=SU(2)$, over a rotation satisfying a Diophantine condition and satisfying a closeness-to-constants condition, by proving a…

Dynamical Systems · Mathematics 2018-01-29 Nikolaos Karaliolios

We study discrete Schroedinger operators with analytic potentials. In particular, we are interested in the connection between the absolutely continuous spectrum in the almost periodic case and the spectra in the periodic case. We prove a…

Spectral Theory · Mathematics 2011-04-19 Mira Shamis

We generalize the approach to localization in one dimension introduced by Kunz-Souillard, and refined by Delyon-Kunz-Souillard and Simon, in the early 1980's in such a way that certain correlations are allowed. Several applications of this…

Spectral Theory · Mathematics 2019-02-25 David Damanik , Anton Gorodetski

We prove that the quasi-periodic Schr\"{o}dinger operator with a finitely differentiable potential has purely absolutely continuous spectrum for all phases if the frequency is Diophantine and the potential is sufficiently small in the…

Dynamical Systems · Mathematics 2021-03-30 Ao Cai

For analytic quasi-periodic Schr\"odinger cocycles, You and Zhang [9] proved that the Lyapunov exponent is H\"older continuous for weak Liouville frequency. In this paper, we prove that the H\"older continuity also holds if the analytic…

Mathematical Physics · Physics 2018-07-17 Licheng Fang , Daxiong Piao

Consider a quasi-periodic Schr\"odinger operator $H_{\alpha,\theta}$ with analytic potential and irrational frequency $\alpha$. Given any rational approximating $\alpha$, let $S_+$ and $S_-$ denote the union, respectively, the intersection…

Mathematical Physics · Physics 2012-02-14 S. Jitomirskaya , C. A. Marx

We prove that the spectrum of a Schrodinger operator that is periodic in certain directions and super-exponentially decaying in the others is purely absolutely continuous.

Mathematical Physics · Physics 2007-05-23 Nikolai Filonov , Frederic Klopp

Introducing and studying the pattern frequency algebra, we prove the analogue of L\"uck's approximation theorems on $L^2$-spectral invariants in the case of aperiodic order. These results imply a uniform convergence theorem for the…

Functional Analysis · Mathematics 2007-05-23 Gábor Elek

We study discrete quasiperiodic Schr\"odinger operators on $\ell^2(\zee)$ with potentials defined by $\gamma$-H\"older functions. We prove a general statement that for $\gamma >1/2$ and under the condition of positive Lyapunov exponents,…

Mathematical Physics · Physics 2015-08-18 S. Jitomirskaya , R. Mavi

We prove a reducibility result for a linear wave equation with a time quasi-periodic driving on the one dimensional torus. The driving is assumed to be fast oscillating, but not necessarily of small size. Provided that the external…

Analysis of PDEs · Mathematics 2023-01-20 Luca Franzoi