Shadow band in the one-dimensional infinite-U Hubbard model

We show that the factorized wave function of Ogata and Shiba can be used to calculate the k dependent spectral functions of the one-dimensional, infinite-U Hubbard model, and of some extensions to finite U. The resulting spectral function is remarkably rich: In addition to low energy features typical of Luttinger liquids, there is a well defined band, which we identify as the shadow band resulting from 2k(F) spin fluctuations. This band should be detectable experimentally because its intensity is comparable to that of the main band for a large range of momenta.