# THRESHOLDS AND MORE BANDS OF A.C. SPECTRUM FOR THE DISCRETE SCHRÖDINGER OPERATOR WITH A MORE GENERAL LONG RANGE CONDITION

Abstract : We continue the investigation of the existence of absolutely continuous (a.c.) spectrum for the discrete Schr\"odinger operator $\Delta+V$ on $\ell^2(\mathbb{Z}^d)$, in dimensions $d\geq 2$, for potentials $V$ satisfying the long range condition $n_i(V-\tau_i ^{\kappa}V)(n) = O(\ln^{-q}(|n|))$ for some $q>2$, $\kappa \in \mathbb{N}$, and all $1 \leq i \leq d$, as $|n| \to \infty$. $\tau_i ^{\kappa} V$ is the potential shifted by $\kappa$ units on the $i^{\text{th}}$ coordinate. The difference between this article and \cite{GM2} is that here \textit{finite} linear combinations of conjugate operators are constructed leading to more bands of a.c.\ spectrum being observed. The methodology is backed primarily by graphical evidence because the linear combinations are built by numerically implementing a polynomial interpolation. On the other hand an infinitely countable set of thresholds, whose exact definition is given later, is rigorously identified. Our overall conjecture, at least in dimension 2, is that the spectrum of $\Delta+V$ is void of singular continuous spectrum, and consecutive thresholds are endpoints of a band of a.c. spectrum.
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https://hal-cnrs.archives-ouvertes.fr/hal-03498793
Contributor : Sylvain Golenia Connect in order to contact the contributor
Submitted on : Friday, January 21, 2022 - 2:04:56 PM
Last modification on : Tuesday, January 25, 2022 - 3:04:53 AM

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### Identifiers

• HAL Id : hal-03498793, version 1
• ARXIV : 2201.09545

### Citation

Sylvain Golénia, Marc-Adrien Mandich. THRESHOLDS AND MORE BANDS OF A.C. SPECTRUM FOR THE DISCRETE SCHRÖDINGER OPERATOR WITH A MORE GENERAL LONG RANGE CONDITION. 2022. ⟨hal-03498793⟩

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