Thomas Schäfer

TL;DR: In this article, the impact of nonlocal electronic correlations at all length scales on the Mott-Hubbard metal-insulator transition in the unfrustrated two-dimensional Hubbard model was studied.

TL;DR: In this paper, a comparative study of state-of-the-art quantum many-body methods is performed using the half-filled Hubbard model at weak coupling as testing grounds, with two numerically exact methods (diagrammatic and determinantal quantum Monte Carlo) serving as a benchmark.

TL;DR: Dynamical mean-field calculations demonstrate that the first nonperturbative precursors of the Mott physics are unambiguously identified well inside the metallic regime by the divergence of the local Bethe-Salpeter equation in the charge channel.

TL;DR: It is demonstrated how to identify which physical processes dominate the low-energy spectral functions of correlated electron systems through an analysis of the equation of motion for the electron self-energy in its charge, spin, and particle-particle representations.

TL;DR: In this article, the authors have implemented the dynamical vertex approximation in its full parquet-based version to include spatial correlations on all length scales and in all scattering channels, applied to study the electronic self-energies and the spectral properties of finite-size one-dimensional Hubbard models with periodic boundary conditions.