Dynamical downfolding for localized quantum states

Abstract We introduce an approach to treat localized correlated electronic states in the otherwise weakly host medium. Here, environment is dynamically downfolded on subspace. It captured via renormalization of one and two quasiparticle interaction terms which are evaluated using many-body perturbation theory. outline strategy how take dynamical effects into account by going beyond static limit approximation. Further, we efficient stochastic implementation that enables treating with a large number electrons at minimal computational cost. For small explicitly subspace, critical. demonstrate methodology reproducing optical excitations negatively charged NV center defect diamond, agree experimental results.