Prof. Dr. Peter Kopietz
The group of Prof. Kopietz uses mainly analytical methods to study strongly interacting quantum mechanical many-body systems in condensed matter. These include not only systems of interacting bosons or fermions, but also effective models describing only the spin degree of freedom of the electrons, such as the Heisenberg model. We are especially interested in universal and emergent low-energy and long-wavelength properties of these systems, which can be calculated by means of the powerful analytical methods of quantum field theory, such as Feynman-diagrams, Greens functions, functional integrals, and renormalization group methods. Our goal is to gain a deep understanding of the nature of phase transitions between different states of matter. Recently we have also used renormalization group methods to study the dynamics of many-body systems out of equilibrium.
Another focus of the research in the group of Prof. Kopietz is the quantum theory of magnetism. Here we use quantum field theoretical methods to calculate thermodynamic as well as dynamic properties of magnets, such as the specific heat, the magnetization, the magnetic susceptibility, and the attenuation of sound. In this field we collaborate with several experimental groups and help them to interpret their measurements probing various aspects of magnetic materials.
Publications on arXiv.