Algebraic properties of the Fermi variety for periodic graph operators

J Fillman, W Liu, R Matos - Journal of Functional Analysis, 2024 - Elsevier
We present a method to estimate the number of irreducible components of the Fermi
varieties of periodic Schrödinger operators on graphs in terms of suitable asymptotics. Our …

Flat bands of periodic graphs

M Sabri, P Youssef - Journal of Mathematical Physics, 2023 - pubs.aip.org
We study flat bands of periodic graphs in a Euclidean space. These are infinitely degenerate
eigenvalues of the corresponding adjacency matrix, with eigenvectors of compact support …

Fermi isospectrality for discrete periodic Schrödinger operators

W Liu - Communications on Pure and Applied Mathematics, 2024 - Wiley Online Library
Abstract Let Γ= q 1 Z⊕ q 2 Z⊕…⊕ qd Z Γ=q_1Z⊕q_2Z⊕...⊕q_dZ, where ql∈ Z+ q_l∈Z_+,
l= 1, 2,…, dl=1,2,...,d, are pairwise coprime. Let Δ+ V Δ+V be the discrete Schrödinger …

Proof of geometric Borg's Theorem in arbitrary dimensions

W Liu - arXiv preprint arXiv:2306.16412, 2023 - arxiv.org
Let $\Delta+ V $ be the discrete Schr\" odinger operator, where $\Delta $ is the discrete
Laplacian on $\mathbb {Z}^ d $ and the potential $ V:\mathbb {Z}^ d\to\mathbb {C} $ is …

Floquet isospectrality for periodic graph operators

W Liu - Journal of Differential Equations, 2023 - Elsevier
Abstract Let Γ= q 1 Z⊕ q 2 Z⊕⋯⊕ qd Z with arbitrary positive integers ql, l= 1, 2,⋯, d. Let Δ
discrete+ V be the discrete Schrödinger operator on Z d, where Δ discrete is the discrete …

Bloch varieties and quantum ergodicity for periodic graph operators

W Liu - Journal d'Analyse Mathématique, 2024 - Springer
For periodic graph operators, we establish criteria to determine the overlaps of spectral band
functions based on Bloch varieties. One criterion states that for a large family of periodic …

The curious spectra and dynamics of non-locally finite crystals

J Kerner, O Post, M Sabri, M Täufer - arXiv preprint arXiv:2411.14965, 2024 - arxiv.org
This paper is devoted to the investigation of the spectral theory and dynamical properties of
periodic graphs which are not locally finite but carry non-negative, symmetric and summable …

Ergodic theorems for continuous-time quantum walks on crystal lattices and the torus

AB de Monvel, M Sabri - arXiv preprint arXiv:2312.04492, 2023 - arxiv.org
We give several quantum dynamical analogs of the classical Kronecker-Weyl theorem,
which says that the trajectory of free motion on the torus along almost every direction tends …

Ergodic Theorems for Continuous-Time Quantum Walks on Crystal Lattices and the Torus

A Boutet de Monvel, M Sabri - Annales Henri Poincaré, 2024 - Springer
We give several quantum dynamical analogs of the classical Kronecker–Weyl theorem,
which says that the trajectory of free motion on the torus along almost every direction tends …

Dispersion on certain Cartesian products of graphs

K Ammari, M Sabri - Spring School on Control & Inverse Problems, 2022 - Springer
In this short note, we prove a sharp dispersive estimate ∥ e i t H f ∥ ∞ < t − d ∕ 3 ∥ f ∥ 1 \documentclass[12pt]{minimal}
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