All-Disorder Localization for the One-Dimensional Anderson Model with Power-Law Hopping

Abstract

We consider the one-dimensional random operator \[ (H_{λ,ω}u)(n) = \sum_{m\ne n}\frac{u(m)}{|n-m|^r} +λω_nu(n), \] where the random variables $ω_n$ are independent and uniformly distributed on $[-1,1]$ (i.e., \mbox{$ω_n\stackrel{\mathrm{i.i.d.}}{\sim}\operatorname{Unif}[-1,1]$}). For every $λ>0$ and $r>3/2$, we prove that $H_{λ,ω}$ almost surely has pure point spectrum and admits an orthonormal eigenbasis $\{ψ_j\}$ satisfying \[ \sum_{n\in\bbZ}(1+|n|)^{2τ}|ψ_j(n)|^2<\infty \qquad \text{for every }j\text{ and }0\leτ<r-\frac32. \] These conclusions establish spectral localization, thereby rigorously confirming the prediction of earlier analytical and numerical studies in the physics literature, which identified $r=3/2$ as the marginal exponent.