CHARGE CURRENTS OF SPIN EXCITATIONS IN ONE-DIMENSIONAL HUBBARD-MODEL

The current-carrying states in a one-dimensional system of interacting electrons are considered. The new exact results for the Hubbard model and for the bosonization method are used. Away from half filling both spin and charge excitations were found to carry currents which are pr oportional to their momenta for most cases. Being in a qualitative agr eement with a single-particle picture of the noninteracting 1D Fermi g as, this result contradicts the spin-charge separation concept, since it is usually derived, e.g., from the bosonization approach or in stro ng repulsion picture. The paradox can be resolved by taking into accou nt the spectrum parabolicity and re-examining the structure of the cur rent operator within the bosonization approach.