AG — Prof. Heiko Rieger — Statistical Physics

Our research team works on a broad spectrum of projects from statistical physics, which is the branch of theoretical physics that seeks to understand the emergence of specific macroscopic properties of systems with many, microscopic interacting particles. Our research ranges from quantum many body physics to theoretical biophysics, with a particular focus on dynamical processes far from equilibrium.

Quantum statistical physics is concerned with collective phenomena in systems with many quantum mechanical degrees of freedom (electrons, bosons, spins, qbits, etc). Paradigmatic examples, also studied in our research group, are quantum phase transitions, where macroscopic properties of a strongly inteacting quantum many body system change dramatically at zero temerature by tuning for instance an external field. Another example is the quantum relaxation of many particle systems after sudden changes of an external field, which is experimentally observable for instance in ultracold atoms in optical lattices.

The last example is also representative for systems far from equilibrium investigated in our group. Especially the non-equilibrium dynamics in disordered systems takes place on enormously long time scales (in glasses theoretically even time scales of the order of the age of the universe) that it is called aging, which we studied intensively in the past. Currently we focus on stochastic processes like random walks on complex networks and on imbibition and fluid flow in nano-porous media.

Biological systems are manifestly systems far from equilibrium, since they consume continuously energy for instance in the form of ATP. We are interested in understanding the physical determinants of tumor growth, in particular the process of vascularization, interstitial flow and fingering instabilities. In collaboration with several groups from the life science departments of the Saarland University we have ongoing projects on intracellular transport during cell polarization.