Effect of three-body clusters in the ground-state properties of spin-polarized liquid 3He

The ground-state energy of polarized and unpolarized liquid 3He is calculated using the variational theory. A variational wave function is constrained to be normalized appropriately by including the three-body terms in the cluster expansion of the two-body radial distribution function. The higher-order terms have been found to be important to obtain an equation of state which is in agreement with experimental data. The saturation density of unpolarized liquid 3He was found to be 0.267σ−3, which decreases by enhancing the polarization. For all relevant densities, the ground-state energy of the spin-polarized system is higher than that in the unpolarized case.