Subordinacy theory for long-range operators: hyperbolic geodesic flow insights and monotonicity theory

Fuente: arXiv
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Main Authors: Wang, Zhenfu, Xu, Disheng, Zhou, Qi
Format: Preprint
Published: 2025
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author Wang, Zhenfu
Xu, Disheng
Zhou, Qi
author_facet Wang, Zhenfu
Xu, Disheng
Zhou, Qi
contents We introduce a comprehensive framework for subordinacy theory applicable to long-range operators on $\ell^2(\mathbb Z)$, bridging dynamical systems and spectral analysis. For finite-range operators, we establish a correspondence between the dynamical behavior of partially hyperbolic (Hermitian-)symplectic cocycles and the existence of purely absolutely continuous spectrum, resolving an open problem posed by Jitomirskaya. For infinite-range operators-where traditional cocycle methods become inapplicable-we characterize absolutely continuous spectrum through the growth of generalized eigenfunctions, extending techniques from higher-dimensional lattice models. Our main results include the first rigorous proof of purely absolutely continuous spectrum for quasi-periodic long-range operators with analytic potentials and Diophantine frequencies-in particular, the first proof of the all-phases persistence for finite-range perturbations of subcritical almost Mathieu operators-among other advances in spectral theory of long-range operators. The key novelty of our approach lies in the unanticipated connection between stable/vertical bundle intersections in geodesic flows-where they detect conjugate points-and their equally fundamental role in governing (de-)localization for Schrödinger operators. The geometric insight, combined with a novel coordinate-free monotonicity theory for general bundles (including its preservation under center-bundle restrictions) and adapted analytic spectral and KAM techniques, enables our spectral analysis of long-range operators.
format Preprint
id arxiv_https___arxiv_org_abs_2506_23098
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Subordinacy theory for long-range operators: hyperbolic geodesic flow insights and monotonicity theory
Wang, Zhenfu
Xu, Disheng
Zhou, Qi
Dynamical Systems
Mathematical Physics
Spectral Theory
We introduce a comprehensive framework for subordinacy theory applicable to long-range operators on $\ell^2(\mathbb Z)$, bridging dynamical systems and spectral analysis. For finite-range operators, we establish a correspondence between the dynamical behavior of partially hyperbolic (Hermitian-)symplectic cocycles and the existence of purely absolutely continuous spectrum, resolving an open problem posed by Jitomirskaya. For infinite-range operators-where traditional cocycle methods become inapplicable-we characterize absolutely continuous spectrum through the growth of generalized eigenfunctions, extending techniques from higher-dimensional lattice models. Our main results include the first rigorous proof of purely absolutely continuous spectrum for quasi-periodic long-range operators with analytic potentials and Diophantine frequencies-in particular, the first proof of the all-phases persistence for finite-range perturbations of subcritical almost Mathieu operators-among other advances in spectral theory of long-range operators. The key novelty of our approach lies in the unanticipated connection between stable/vertical bundle intersections in geodesic flows-where they detect conjugate points-and their equally fundamental role in governing (de-)localization for Schrödinger operators. The geometric insight, combined with a novel coordinate-free monotonicity theory for general bundles (including its preservation under center-bundle restrictions) and adapted analytic spectral and KAM techniques, enables our spectral analysis of long-range operators.
title Subordinacy theory for long-range operators: hyperbolic geodesic flow insights and monotonicity theory
topic Dynamical Systems
Mathematical Physics
Spectral Theory
url https://arxiv.org/abs/2506.23098