Self Consistent Auxiliary Field Quantum Monte Carlo Method for Realistic Materials

The auxiliary field quantum Monte Carlo (QMC) calculations in interacting fermion systems require a constraint to control the sign and phase problem. The constraint involves an input trial wave function which restricts the random walks. We introduce a systematically improvable constraint for realistic materials. An independent-particle calculation is coupled to the phaseless auxiliary-field QMC calculation and the independent-particle solution is used as the constraint in QMC. The constraint is optimized by the self-consistency between the QMC and independent-particle calculations. We demonstrate this approach in transition metal oxides. Connection with other electronic structure methods will be discussed.