Linear scaling QMC

"Linear scaling of the local energy in quantum Monte Carlo" JCP 119, 1307 by Manten and Luchow.

Cutting off the orbitals and using sparse matrix computations for the determinant, and cutting of the Jastrow factor are the time consuming parts.

One interesting point - they use a topological cutoff for the orbitals rather than a strictly spatial cutoff.

This is the scaling of the local energy with the number of electrons - I'm curious how the correlation time varies with system size.