Lattice susceptibility calculations via a generalized CT-Hyb QMC DMFT solver

Linear-response functions are essential for comparing theory to experiments, and yet for strongly correlated systems their calculation is very challenging. The state-of-the-art technique for real materials is based on the dynamical mean-field (DMFT) approach and the local-vertex approximation. The bottleneck of this method is the calculation of local susceptibilities. Here we present an efficient scheme based on the massively-parallel general implementation of the continuous-time quantum Monte Carlo impurity solver of Ref. $[$1$]$. We use both the Legendre polynomial representation and a recently proposed numerical basis $[$2$]$, and compare efficiency. To calculate lattice susceptibilities we solve the Bethe-Salpeter equation. We present results for the static and dynamical response functions of representative systems: La${}_{2-x}$Sr${}_x$CuO${}_4$ and several orbitally ordered materials.