Downfolding from ab initio to interacting model Hamiltonians : comprehensive analysis and benchmarking of the DFT+cRPA approach
Model Hamiltonians are regularly derived from first principles to describe correlated matter. However, the standard methods for this contain a number of largely unexplored approximations. For a strongly correlated impurity model system, here we carefully compare a standard downfolding technique with the best possible ground-truth estimates for charge-neutral excited-state energies and wave functio