BETHE ANSATZ STUDY OF 1+1 DIMENSIONAL HUBBARD-MODEL

A wave function of Bethe ansatz form is used to obtain approximate solutions for a 1 + 1 dimensional Hubbard model. In this model a helical structure with infinite diameter is constructed to mimic the square lattice. Betheansatz analysis is performed along the helical line. By including the hopping integrals in perpendicular direction, the solutions show some recovery of two dimensional character. At half-filling, the system undergoes Mott transition, the critical value of on-site repulsion obtained by this scheme is smaller than that of the mean-field theory. For a given particle density, the energy level of corresponding one dimensional model is extended to a "band". The relation of the results to the properties of two dimensional strong-correlation system is discussed.