STRONG EIGENFUNCTION CORRELATIONS NEAR THE ANDERSON-LOCALIZATION TRANSITION

We study the overlap of two different eigenfunctions as compared with self-overlap in the framework of an infinite-dimensional version of th e disordered tight-binding model. Despite a very sparse structure of t he eigenstates in the vicinity of the Anderson transition, their mutua l overlap is still found to be of the same order as self-overlap as lo ng as the energy separation is smaller than a critical value. The latt er fact explains the robustness of the Wigner-Dyson level statistics e verywhere in the phase of extended states. The same picture is expecte d to hold for usual d-dimensional conductors, ensuring the s(beta) for m of the level repulsion at a critical point.