  In this paper, we address the role of electron-electron interactions on the
velocities of spin and charge transport in one-dimensional systems typified by
conjugated polymers. We employ the Hubbard model to model electron-electron
interactions. The recently developed technique of time dependent Density Matrix
Renormalization Group (tdDMRG) is used to follow the spin and charge evolution
in an initial wavepacket described by a hole doped in the ground state of the
neutral system. We find that the charge and spin velocities are different in
the presence of correlations and are in accordance with results from earlier
studies; the charge and spin move together in the noninteracting picture while
interaction slows down only the spin velocity. We also note that dimerization
of the chain only weakly affects these velocities.
