Recent Bethe-ansatz results for the spin-1/2 XXZ model in a ring with a magnetic flux are used to identify current-carrying states and interpreted in terms of Haldane’s Luttinger-liquid theory. The velocity associated with these current excitations in a Luttinger-liquid picture is extracted and compared with the velocities corresponding to charge and sound-wave excitations. The validity of the scaling relation between velocities predicted by Luttinger-liquid theory is confirmed from exact, independent evaluation of the three velocities.

• Received 16 August 1991

DOI:https://doi.org/10.1103/PhysRevB.46.14217