Optical response in one dimensional Mott Insulators
  We study the optical response of a Mott Hubbard system in the framework of the half--filled Extended Hubbard Model using the Density Matrix Renormalization Group (DMRG) method. We discuss the appearance of excitonic features inside the spectral gap as the system goes from the Spin Density Wave (SDW) to the Charge Density Wave (CDW) phase. 
S. S. Kancharla and C. J. Bolech (Rutgers University)