Hamiltonian symmetries in auxiliary-field quantum Monte Carlo calculations for electronic structure

@article{Motta2019HamiltonianSI,
  title={Hamiltonian symmetries in auxiliary-field quantum Monte Carlo calculations for electronic structure},
  author={Mario Motta and Shiwei Zhang and Garnet Kin-Lic Chan},
  journal={Physical Review B},
  year={2019}
}
We describe how to incorporate symmetries of the Hamiltonian into auxiliary-field quantum Monte Carlo (AFQMC) calculations. Focusing on the case of Abelian symmetries, we show that the computational cost of most steps of an AFQMC calculation is reduced by N^(-1)_k, where N_k is the number of irreducible representations of the symmetry group. We apply the formalism to a molecular system as well as to several crystalline solids. In the latter case, the lattice translational group provides… 

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