SPECTRAL-FUNCTION OF THE 1D HUBBARD-MODEL IN THE U-]+INFINITY LIMIT

We show that the one-particle spectral functions of the one-dimensional Hubbard model diverge at the Fermi energy like \omega - epsilon(F)\(-3/8) in the U --> + infinity limit. The Luttinger liquid behavior to \omega - epsilon(F)\(alpha), where alpha --> 1/8 as U --> + infinity, should be limited to \omega - epsilon(F)\ similar to t(2)/U (for U large but finite), which shrinks to a single point, omega = epsilon(F), in that limit. The consequences for the observation of the Luttinger liquid behavior in photoemission and inverse photoemission experiments are discussed.