In this paper we study the spectral properties of a family of discrete one-dimensional quasi-periodic Schrödinger operators with discontinuous potential. In large disorder with piecewise analytic potential, under some suitable transversality condition and a Diophantine rotation number, we prove using basically KAM theory that the spectrum of this operator have a large punctual component. Moreover, the most of its eigenvectors are $\ell ^2$-localized in one site. We give an explicit estimation of the measure of the punctual spectrum and we prove that the set of phases for which this spectrum is empty have zero Hausdorff dimension.
Dans cet article, nous étudions les propriétés spectrales d’une famille d’opérateurs de Schrödinger quasi-périodiques discrets unidimensionnels avec potentiel discontinu. Pour un désordre important avec un potentiel analytique par morceaux, sous des conditions de transversalité appropriées et un nombre de rotation diophantien, nous démontrons essentiellement à l’aide de la théorie KAM que le spectre de cet opérateur possède une grande composante ponctuelle. De plus, la majorité de ses fonctions propres sont $\ell ^2$-localisées en un seul site. Nous fournissons une estimation explicite de la mesure du spectre ponctuel et prouvons que l’ensemble des phases pour lesquelles ce spectre est vide a une dimension de Hausdorff nulle.
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Keywords: Quasi-periodic Schrödinger operators, pure point spectrum, eigenfunctions
Mots-clés : Opérateurs de Schrödinger quasi-périodiques, spectre purement ponctuel, fonctions propres
Walid Refai 1

@article{CRMATH_2025__363_G4_425_0, author = {Walid Refai}, title = {On the point spectrum of quasi-periodic {Schr\"odinger} operators}, journal = {Comptes Rendus. Math\'ematique}, pages = {425--428}, publisher = {Acad\'emie des sciences, Paris}, volume = {363}, year = {2025}, doi = {10.5802/crmath.730}, language = {en}, }
Walid Refai. On the point spectrum of quasi-periodic Schrödinger operators. Comptes Rendus. Mathématique, Volume 363 (2025), pp. 425-428. doi : 10.5802/crmath.730. https://comptes-rendus.academie-sciences.fr/mathematique/articles/10.5802/crmath.730/
[1] On nonperturbative localization with quasi-periodic potential, Ann. Math. (2), Volume 152 (2000) no. 3, pp. 835-879 | DOI | MR | Zbl
[2] Discrete one-dimensional quasi-periodic Schrödinger operators with pure point spectrum, Acta Math., Volume 179 (1997) no. 2, pp. 153-196 | DOI | MR | Zbl
[3] Dynamical systems and small divisors, Lecture Notes in Mathematics, 1784, Springer, 2002, viii+191 pages | DOI | MR
[4] Localization for a class of one-dimensional quasi-periodic Schrödinger operators, Commun. Math. Phys., Volume 132 (1990) no. 1, pp. 5-25 | DOI | MR | Zbl
[5] Operators with singular continuous spectrum. III. Almost periodic Schrödinger operators, Commun. Math. Phys., Volume 165 (1994) no. 1, pp. 201-205 | DOI | MR | Zbl
[6] Localization of the discrete one-dimensional quasi-periodic Schrödinger operators, Math. Methods Appl. Sci., Volume 47 (2024) no. 12, pp. 10435-10443 | DOI | MR | Zbl
[7] Anderson localization for one-dimensional difference Schrödinger operator with quasiperiodic potential, J. Stat. Phys., Volume 46 (1987) no. 5-6, pp. 861-909 | DOI | MR | Zbl
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