Optical conductivity in normal-state fullerene superconductors

We calculate the optical conductivity sigma(omega) in the normal-state full erene superconductors by self-consistently including the impurity scatterin gs, the electron-phonon, and electron-electron Coulomb interactions. The fi nite bandwidth of the fullerenes and the vertex corrections are explicitly considered in calculating the renormalized Green's function, sigma(omega) i s obtained by calculating the current-current correlation function with the renormalized Green's function in the Matsubara frequency and then performi ng analytic continuation to the real frequency at finite temperature. The D rude weight in sigma(omega) is strongly suppressed due to the interactions and transfered to the mid-infrared region around and above 0.06 eV, which i s somewhat less pronounced and much broader compared with the experimental observation by DeGiorgi et al.