The density of states and local eigenvalue statistics for random band matrices of fixed width

Abstract

We prove that the local eigenvalue statistics for $d=1$ random band matrices with fixed bandwidth and, for example, Gaussian entries, is given by a Poisson point process and we identify the intensity of the process. The proof relies on an extension of the localization bounds of Schenker [23] and the Wegner and Minami estimates. These two estimates are proved using averaging over the diagonal disorder. The new component is a proof of the uniform convergence and the smoothness of the density of states function. The limit function, known to be the semicircle law with a band-width dependent error [5, 14, 15, 20], is identified as the intensity of the limiting Poisson point process. The proof of these results for the density of states relies on a new result that simplifies and extends some of the ideas used by Dolai, Krishna, and Mallick [16]. These authors proved regularity properties of the density of states for random Schrödinger operators (lattice and continuum) in the localization regime. The proof presented here applies to the random Schrödinger operators on a class of infinite graphs treated in [16] and extends the results of [16] to probability measures with unbounded support. The method also applies to fixed bandwidth RBM for $d=2,3$ provided certain localization bounds are known.