Ground states of polarized and unpolarizedHe3

A variational computation of the ground-state energy of a Fermi fluid similar to ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ is made using Slater-Jastrow-type wave functions. The calculation of the energy is performed by an exact Monte Carlo algorithm. The two cases of the polarized and unpolarized fluids are considered in the domain of densities corresponding to a stable thermodynamic state. For these densities the energy of the polarized fluid is shown to be lower than the energy of the unpolarized fluid. A comparison is made with the previous approximate computations of the ground state of unpolarized ${}_{}{}^3{}_{}{}^{}\mathrm{He}$.