Theory of Condensed Matter and Many Body Systems (S. Eggert)

The research of our group focuses on several aspects of interacting quantum many-body systems in which the correlation effects are so strong, that their properties cannot be described by perturbation theory from an independent particle picture. This is frequently the case in low dimensional electron systems, such as nanostructured quantum wires (Luttinger liquids), low dimensional antiferromagnets, carbon nanotubes, quasi-one-dimensional metals, and fractional quantum Hall edge states. The interest in these systems seems to be ever increasing due to the rapid experimental progress in nanoscale physics, ultra-cold quantum gases and the availability of materials with intrinsically low-dimensional behavior such as high-temperature superconductors.

In order to study these systems it is useful to combine field theoretical methods with advanced numerical techniques. The numerical techniques yield nearly exact results, but are limited by finite temperatures and/or system sizes. On the other hand, field theory techniques give asymptotically exact analytical results in the thermodynamic limit and at low temperatures. The two methods therefore complement each other to give a complete understanding which often allows detailed comparisons with experiments. Most recently we have focused on supersolid phases, the density of states in tunneling experiments, dynamic decoherence properties, and scattering from impurities and boundaries.

See also: publication list.