CTSEG: A segment picture quantum impurity solver based on TRIQS

Electron-electron interactions are a key determinant of the electrical and optical response properties in solid-state materials.Yet, the many-electron problem is outstandingly difficult, and can be tackled analytically only when interactions are weak, or in rare exactly solvable cases.One of the popular numerical schemes for addressing strongly interacting systems is dynamical mean-field theory (DMFT;Georges et al., 1996).In DMFT, the many-body problem formulated on a crystal lattice is self-consistently mapped onto a single atom (or impurity) immersed in an effective environment (or bath).The remaining computational task is then the solution of the impurity problem, which can be carried out through various quantum Monte Carlo algorithms (Gull et al., 2011).Here, we present an implementation of the continous time hybridization expansion algorithm in the segment picture (CTSEG) based on TRIQS, a comprehensive library for the numerical investigation of interacting quantum systems (Parcollet et al., 2015).