Pseudoparticle Description of the 1D Hubbard Model Electronic Transport   Properties
  We extend the pseudoparticle transport description of the Hubbard chain to all energy scales. In particular we compute the mean value of the electric current transported by any Bethe-ansatz state and the transport masses of the charge carriers. We present numerical results for the optical conductivity of the model at half-filling for values of U/t=3 and 4. We show that these are in good agreement with the pseudoparticle description of the finite-energy transitions involving new pseudoparticle energy bands. 
N. M. R. Peres, J. M. P. Carmelo, D. K. Campbell, and A. W. Sandvik