MAGNETIC-PROPERTIES OF THE ONE-DIMENSIONAL SUPERSYMMETRIC T-J MODEL

Starting with the known exact solution of the one-dimensional supersymmetric t-J model, we investigate ground-state properties of the system in the presence of an external magnetic field. By analytical calculations we find a representation of the magnetization curves and the susceptibility using the dressed charge matrix and the charge and spin densities; the dressed properties are given by a set of coupled integral equations which are derived from the Bethe ansatz equations in the thermodynamic limit. Some special results are found analytically, namely the magnetic field at which saturation occurs and the corresponding susceptibility. Furthermore we show the vanishing of the lower critical field. The dependence of magnetization and susceptibility on the magnetic field is calculated numerically for various particle densities.