Iterative backflow renormalization procedure for many-body ground-state wave functions of strongly interacting normal Fermi liquids

We show how a ground-state trial wave function of a Fermi liquid can be systematically improved by introducing a sequence of renormalized coordinates through an iterative backflow transformation. We apply this scheme to calculate the ground-state energy of liquid He3 in two dimensions at freezing density using variational and fixed-node diffusion Monte Carlo. Compared with exact transient estimate results for systems with a small number of particles, we find that variance extrapolations provide accurate results for the true ground state together with stringent lower bounds. For larger systems these bounds can in turn be used to quantify the systematic bias of fixed-node calculations. These wave functions are size consistent and the scaling of their computational complexity with the number of particles is the same as for standard backflow wave functions.