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arXiv · 1408.5660

Extended States for the Schr\"odinger Operator with Quasi-periodic Potential in Dimension Two

Yulia Karpeshina·Roman Shterenberg
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Abstract

We consider a Schr\"odinger operator $H=-\Delta+V(\vec x)$ in dimension two with a quasi-periodic potential $V(\vec x)$. We prove that the absolutely continuous spectrum of $H$ contains a semiaxis and there is a family of generalized eigenfunctions at every point of this semiaxis with the following properties. First, the eigenfunctions are close to plane waves $e^{i\langle \vec \varkappa,\vec x\rangle}$ at the high energy region. Second, the isoenergetic curves in the space of momenta $\vec \varkappa$ corresponding to these eigenfunctions have a form of slightly distorted circles with holes (Cantor type structure). A new method of multiscale analysis in the momentum space is developed to prove these results. The result is based on the previous paper [1] on quasiperiodic polyharmonic operator $(-\Delta)^l+V(\vec x)$, $l>1$. We address here technical complications arising in the case $l=1$. However, this text is self-contained and can be read without familiarity with [1].

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Yulia Karpeshina, Roman Shterenberg. 2014-08-25. Extended States for the Schr\"odinger Operator with Quasi-periodic Potential in Dimension Two. https://arxiv.org/abs/1408.5660

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