Optimized correlations inspired by perturbation theory

We study the accuracy of analytical wave function based many-body methods derived by energy minimization of a Jastrow-Feenberg ansatz for electrons (`Fermi hypernetted chain / Euler Lagrange' approach). Approximations to avoid the complexity of the fermion problem are chosen to parallel successful boson theories and be computationally efficient. For the three-dimensional homogeneous electron gas, we calculate the correlation energy, the pair distribution function and the static structure function in comparison with simulation results. We also present a new variant of theory, which is interpreted as approximate, self-consistent sum of ladder and ring diagrams of perturbation theory. The theory performs particularly well in the highly dilute density regime.