Long-range correlations in nonequilibrium quantum Lorentz gases

Spatial correlation functions in noninteracting disordered electronic systems maintained in a nonequilibrium steady state are studied using diagrammatic perturbation theory. The classical result obtained in a previous study is recovered for the correlation function of microscopic number densities of the moving particle and scatterer; it decays as 1/r(2) in three dimensions. The number-density correlation function of moving particles is also calculated. We find that spatial correlations at second order in a concentration gradient decay linearly in three dimensions at low temperatures. The connection of this result with mesoscopic fluctuations is discussed.