Kolloquien

Fermi liquids are interacting fermion systems whose elementary excitations and low temperature properties resemble those of a non-interacting Fermi gas. In particular, the conduction electrons in conventional metals form a Fermi liquid, and many metallic properties can be understood in terms of a simple Fermi gas model, as is frequently done in solid state physics courses. The at first sight surprising immunity of Fermi liquids to interactions is due to Pauli's exclusion principle, which follows from the fermionic statistics. Fermi liquid theory has been developed by Lev Landau already in the 1950s, but it was formulated on mathematically rigorous grounds only in the 1990s.   mehr...

Scattering of light is one of the most elementary processes for atoms and is discussed in many textbooks. We have performed several light scattering experiments which reveal fundamental quantum aspects. At ultralow temperatures, light scattering is suppressed or enhanced by Pauli blocking and bosonic stimulation, respectively. Light scattering can distinguish a superfluid from a Mott insulator. Finally, we have experimentally investigated whether light is coherent and incoherent when scattered by single atoms.   mehr...

Robots have achieved unprecedented performance jumps over the last decade. As of today, however, robot design and build are laborious and suboptimal, costly and constitute a major limitation in achieving the anticipated robotics revolution. At the same time, we see intelligent machines that learn and perform tasks, and are able to generalize their skills to new contexts.   mehr...

The microscopic quantum world is increasingly present in our everyday lives and technology. To keep up, we need to advance theoretical and numerical tools capable of handling highly dimensional, coupled, and correlated quantum systems. For molecules, this task is especially challenging due to strong, anharmonic interactions among nuclei and electrons.   mehr...