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

We consider many-body quantum phenomena in low-dimensions, where correlations dominate the collective behavior so that universal behavior emerges. Interesting quantum lattice systems with spin and charge degrees of freedom are found in materials as well as in ultra-cold quantum gases, where frustration, fractional excitations, supersolids, and anyons lead to exciting physical phenomena and novel quantum phases. Also interesting dynamic effects are studied, which are induced using quenches or time-periodic driving. More recently we consider spintronics applications by calculating the transport in magnetic nano-wires.

In order to study these systems it is useful to combine field theoretical methods with advanced numerical simulation 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.

See also: publication list.