DECAY PROPERTIES OF THE FINITE-TEMPERATURE DENSITY-MATRIX IN METALS

Using ordinary Fourier analysis, the asymptotic decay behavior of the density matrix F(r, r') is derived for the case of a metal at a finite electronic temperature. An oscillatory behavior that is damped expone ntially with increasing distance between r and r' is found. The decay rate is not only determined by the electronic temperature, but also by the Fermi energy. The theoretical predictions are confirmed by numeri cal simulations.