Application of the connected-moments expansion to the half-filled Hubbard model

Summary In this paper we have applied the method of connected-moments expansion to investigate the ground state of the half-filled Hubbard model for both the linear chain and the square lattice. The CMX series appear very unstable and give rather poor estimates of the ground-state energies. This seems to suggest that it does not provide a useful method for estimating ground-state energies of this model.