Quantum many-fermion systems in solids that host an enormous number of interacting electrons give rise to a great variety of collective phenomena. Among those are unconventional forms of superconductivity and magnetism that, besides being of fundamental interest, might be used in future quantum materials or devices. Our research explores the mechanisms for these phenomena and the question under which conditions what phases occur in specific model systems on various lattices. Besides standard many-body-theoretical approaches we mainly work with functional renormalization group (fRG) methods that provide effective low-energy actions from which the predominant collective effects can be inferred. Improving these methods is another substantial aspect of our work.

Current funding in collaborative frameworks:

• DFG RTG 1995

Team:

Carsten Honerkamp

Feng Xiong