Exact ground-state properties of one-dimensional Hubbard model in the presence of magnetic field

The exact phase diagram and the ground-state properties of the one-dimensio nal Hubbard model with arbitrary on-site:interaction of electrons are calcu lated over a wide range of magnetic field and electron concentrations by me ans of the Bethe-ansatz formalism. The ground-state properties, including t he total energy, the average spin (magnetization) and spin (magnetic) susce ptibility are investigated for both signs of the interaction strength U/t. The critical behavior near the onset of magnetization and magnetic saturati on are also analyzed. At the onset of magnetization and near the magnetic s aturation the spin susceptibility chi diverges at all U/t for half-filling case n = 1, whereas for n not equal 1 it is always finite. The reverse susc eptibility chi(-1)(U) exhibits anomalous hump, which increases with h or n, and shows discontinuity as U/t --> +/-0 at infinitesimal h --> 0. The anal ytical results for the ground-state properties in strong and weak interacti on limits are in full agreement with our numerical calculations.