GROUND-STATE PROPERTIES OF THE DEGENERATE HUBBARD CHAIN - 1/N-EXPANSION OF THE BETHE-ANSATZ SOLUTION FOR A LATTICE SYSTEM

The one-dimensional Hubbard model with arbitrary degeneracy N (N = 2S + 1, where S is the spin) is integrable if site-occupations of more than two electrons are excluded. The Bethe-ansatz equations are analyzed in the thermodynamic limit in the absence of external fields. In the large N limit they reduce to those of a hard core Bose gas. The 1/N-correction to the leading order result vanishes identically, so that the first corrections are contributions of the order 1/N2. © 1990.