Charge currents of spin excitations in one dimensional Hubbard model
Brazovskii S., Matveenko S., Nozieres P.
We consider current carrying states in a one dimensional system of interacting electrons. The new exact results for the Hubbard model and for the bosonization method are exploited. We find that away from half filling both spin and charge excitations carry currents which are proportional to their momenta for most cases. Being in a qualitative agreement with a single particle picture of the noninteracting Id Fermi gas this result contradicts to the spin-charge separation concept as it is usually derived e.g. from the bosonization approach or in a strong repulsion pictures. The paradox is resolved by taking into account the spectrum parabolicity and reexaming the structure of the current operator within the bosonization approach.