GROUND-STATE OF THE U=INFINITY HUBBARD-MODEL WITH INFINITE-RANGE HOPPING

The ground-state wave function and energy of the Hubbard model with unlimited hopping can be obtained for arbitrary fillings using the transformation recently introduced by Brandt and Giesekus. A simple linear behavior is obtained for the ground-state energy dependence on the number of particles: E(GS) = -2t(L - N), where -t is the hopping energy (t > 0), L is the number of sites, and N is the number of electrons. The ground state shows a very large total spin degeneracy. The system is shown to behave as a Fermi liquid with a spectral weight Z = 1 - N/L for all fillings less than 1 (N less-than-or-equal-to L).