The condensed matter theory group is engaged in various advanced topics in the theoretical description of electronic properties of solids. While in most introductory courses to solid state physics the treatment of a single electron in a periodic potential is a central topic the effects of the interaction of the individual electrons are barely mentioned. In several important system classes interaction effects play a prominent role. These are in the focus of our research. We are aiming at a controlled description of interaction (correlation) effects in models for systems like quantum dots and wires, materials showing Mott-Hubbard metal-insulator transitions and low dimensional systems with competing interactions. These examples are explained shortly below (click onto the corresponding figure).
To achieve this goal, we pursue two complementary routes. On the one hand, analytical techniques based for example on quantum field theoretical concepts (functional integrals, Green functions & Feynman diagrams) are being developed. On the other hand, modern numerical methods (Quantum Monte-Carlo, exact diagonalization & numerical renormalization group methods) are being developed and implemented on high-performance computers.
This research is supported by the SFB602.