We address the question how a correspondence between particle-like excitations in the one-dimensional Hubbard model (i.e. "holons" and "spinons") and the free fermionic picture can be established in the limit of vanishing interaction by studying the finite size spectrum in the framework of the Bethe ansatz. Special attention has to be paid to the case of a vanishing magnetic field where the two bands of excitations in either description are degenerate. The interaction lifts this degeneracy. © 1995.
Frahm, H., & Pfannmüller, M. P. (1995). On the Hubbard model in the limit of vanishing interaction. Physics Letters A, 204(5–6), 347–352. https://doi.org/10.1016/0375-9601(95)00499-S