Auxiliary-field quantum Monte Carlo calculations for systems with long-range repulsive interactions

We report on the first successful attempt to apply the auxiliary-field quantum Monte Carlo technique to the calculation of ground-state properties of systems of many electrons interacting via a Coulomb potential. We have been able to substantially reduce the huge statistical fluctuations arising from the repulsive, long-range character of the interactions, which had so far hindered the application of this method to realistic Hamiltonians for atoms, molecules, and solids. Our technique is demonstrated with calculations of ground-state properties of the simplest molecular and solid-state systems, i.e., the H-2 molecule and the homogeneous electron gas.