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We discuss spectral properties of the one-dimensional Schr\"odinger operator with a potential of the form $\sum V(n)\delta(x-n)$. Our main result says that the absolutely continuous spectum of such an operator covers an interval…

Mathematical Physics · Physics 2025-09-25 Oleg Safronov

We study spectral approximations of Schr\"odinger operators $T=-\Delta+Q$ with complex potentials on $\Omega=\mathbb{R}^d$, or exterior domains $\Omega\subset \mathbb{R}^d$, by domain truncation. Our weak assumptions cover wide classes of…

Spectral Theory · Mathematics 2015-12-08 Sabine Bögli , Petr Siegl , Christiane Tretter

We investigate the spectral properties of Schr\"odinger operators in l^2(Z) with limit-periodic potentials. The perspective we take was recently proposed by Avila and is based on regarding such potentials as generated by continuous sampling…

Spectral Theory · Mathematics 2015-01-05 David Damanik , Zheng Gan

We introduce computational strategies for measuring the ``size'' of the spectrum of bounded self-adjoint operators using various metrics such as the Lebesgue measure, fractal dimensions, the number of connected components (or gaps), and…

Spectral Theory · Mathematics 2024-07-31 Matthew J. Colbrook , Mark Embree , Jake Fillman

We prove several new results on the absolutely continuous spectra of perturbed one-dimensional Stark operators. First, we find new classes of perturbations, characterized mainly by smoothness conditions, which preserve purely absolutely…

Spectral Theory · Mathematics 2007-05-23 M. Christ , A. Kiselev

A new method for finding electronic structure and wavefunctions of electrons in quasiperiodic potential is introduced. To obtain results it uses slightly modified Schrodinger equation in spaces of dimensionality higher than physical space.…

Other Condensed Matter · Physics 2014-10-03 Igor V. Blinov

We give a spectral description of the semi-classical Schrodinger operator with a piecewise linear, complex valued potential. Moreover, using these results, we show how an arbitrarily small bounded perturbation of a non-self-adjoint operator…

Spectral Theory · Mathematics 2007-05-23 P. Redparth

We study half-line Schr\"odinger operators with locally $H^{-1}$ potentials. In the first part, we focus on a general spectral theoretic framework for such operators, including a Last--Simon-type description of the absolutely continuous…

Spectral Theory · Mathematics 2022-06-16 Milivoje Lukić , Selim Sukhtaiev , Xingya Wang

This paper is devoted to the spectral properties of a class of unitary operators with a matrix representation displaying a band structure. Such band matrices appear as monodromy operators in the study of certain quantum dynamical systems.…

Mathematical Physics · Physics 2009-11-07 Olivier Bourget , James S. Howland , Alain Joye

We consider the quasi-periodic Schr\"odinger operator with the non-degenerate Gevrey potential for the Diophantine frequency. We prove that if the coupling number of the potential is large, then the spectrum is homogeneous.

Dynamical Systems · Mathematics 2021-11-29 Yan Yang , Kai Tao

In this article we describe the semi-classical spectrum of a Schrodinger operator on $\mathbb{R}$ with a double well potential. We study the shape of spectrum around the local maximum of the potential. In the classification of singularities…

Spectral Theory · Mathematics 2009-12-18 Olivier Lablée

Spectral components of one-dimensional Schr\"odinger operator with complex potential are investigated. An effective upper bound for the total number of eigenvalues and spectral singularities is established. For dissipative Schr\"odinger…

Classical Analysis and ODEs · Mathematics 2013-06-28 S. A. Stepin

We prove that one-dimensional reflectionless Schr\"odinger operators with spectrum a homogeneous set in the sense of Carleson, belonging to the class introduced by Sodin and Yuditskii, have purely absolutely continuous spectra. This class…

Spectral Theory · Mathematics 2007-05-23 Fritz Gesztesy , Peter Yuditskii

The purpose of this article is to study pseudospectral properties of the one-dimensional Schr\"{o}dinger operator perturbed by a complex steplike potential. By constructing the resolvent kernel, we show that the pseudospectrum of this…

Spectral Theory · Mathematics 2023-10-24 Tho Nguyen Duc

We introduce the periodic Airy-Schr\"odinger operator and we study its band spectrum. This is an example of an explicitly solvable model with a periodic potential which is not differentiable at its minima and maxima. We define a…

Spectral Theory · Mathematics 2017-01-30 H Boumaza , O Lafitte

Let $H$ be a quasiperiodic Schr\"{o}dinger operator generated by a monotone potential, as defined in [16]. Following [20], we study the connection between the Lyapunov exponent $L\left(E\right)$, arithmetic properties of the frequency…

Spectral Theory · Mathematics 2025-04-23 Netanel Levi

We consider discrete one-dimensional Schr\"odinger operators with Sturmian potentials. For a full-measure set of rotation numbers including the Fibonacci case we prove absence of eigenvalues for all elements in the hull.

Mathematical Physics · Physics 2009-10-31 David Damanik , Daniel Lenz

We consider a family of operators $-\Delta+ t V$ with a slowly decaying and oscillating potential $V$. We prove that the absolutely continuous spectrum of this operator is essentially supported by $[0,\infty)$ for almost every $t$.

Spectral Theory · Mathematics 2012-10-22 Oleg Safronov

In this paper, we study spectral properties of a family of quasi-periodic Schrodinger operators on the real line in the adiabatic limit. We assume that the adiabatic iso-energetic curves are extended along the momentum direction. In the…

Mathematical Physics · Physics 2009-11-10 Alexander Fedotov , Frederic Klopp

We show that the spectrum of a Schr\"odinger operator on $\mathbb{R}^n$, $n\ge 3$, with a periodic smooth Riemannian metric, whose conformal multiple has a product structure with one Euclidean direction, and with a periodic electric…

Spectral Theory · Mathematics 2015-08-18 Katsiaryna Krupchyk , Gunther Uhlmann