Fermi-Hypernetted Chain Theory for Liquid ³He: A Reassessment

The Fermi-Hypernetted Chain theory for ³He is reviewed. We develop the theory step by step by the inclusion of elementary diagrams, triplet-correlations, propagator corrections, and spin-correlations. Simulation data are reproduced at each level of implementation. So-called "backflow" correlations are identified to be a consequence of the "mean spherical approximation" which is implicit to the Jastrow-Feenberg wave function for fermions. Results of the best calculation for the energetics and structure functions agree within 0.2-0.3 K with experiments.