Matrix-product-state-based band-Lanczos solver for quantum cluster approaches

In this talk we present a matrix-product-states-based band-Lanczos method as a cluster solver. We introduce and motivate different convergence criteria and discuss their impact on the stability of the results at the example of the variational cluster approximation. In order to increase the stability a continuous energy truncation is included. The capabilities of this method to calculate the self-energy functional are demonstrated for Hubbard-like models on different cluster geometries.