Optical response of electrons in a random potential

Using our recently developed Chebyshev expansion technique for finite-temperature dynamical correlation functions, we numerically study the AC conductivity sigma(omega) of the Anderson model on large cubic clusters of up to 1003 sites. Extending previous results, we focus on the role of the boundary conditions and check the consistency of the DC limit, omega -> 0, by comparing with direct conductance calculations based on a Greens function approach in a Landauer Buttiker-type setup. (c) 2005 Elsevier B.V. All rights reserved.