Top of the spectrum of discrete Anderson Hamiltonians with correlated Gaussian potentials
Giuseppe Cannizzaro, Cyril Labbé, Willem van Zuijlen
TL;DR
This work analyzes the top of the spectrum for discrete Anderson Hamiltonians with correlated Gaussian potentials in growing volumes. It develops a mesoscopic splitting method that exploits decorrelation across well-separated boxes and a local deterministic model defined by a shape function and a fluctuation field, yielding a Poisson limit for the top eigenvalues and precise localisation around the corresponding noise maxima. A key finding is the subtle dependence of localisation centres on the near-origin covariance, captured by the parameter $\tau_L$; depending on its scaling, the relation between eigenfunction localisation and noise maxima can be direct or mediated by a decorated Poisson structure. The results unify into three regimes that mirror the classical i.i.d. Weibull/regularly varying pictures, and they provide a rigorous bridge between extreme value theory of Gaussian fields and spectral theory of random Schrödinger operators with correlated noise.
Abstract
We investigate the top of the spectrum of discrete Anderson Hamiltonians with correlated Gaussian noise in the large volume limit. The class of Gaussian noises under consideration allows for long-range correlations. We show that the largest eigenvalues converge to a Poisson point process and we obtain a very precise description of the associated eigenfunctions near their localisation centres. We also relate these localisation centres with the locations of the maxima of the noise. Actually, our analysis reveals that this relationship depends in a subtle way on the behaviour near $0$ of the covariance function of the noise: in some situations, the largest eigenfunctions are not associated with the largest values of the noise.
