Kontakt: Rainer-G. Ulbrich

Quantum many-body systems with strong interactions are central both in the search for novel phenomena and in the design of novel materials. A fascinating theme are quantum phase transitions, i.e., phase transitions taking place at zero temperature, which have attracted the interest of both theorists and experimentalists in condensed matter physics. The first part of the talk will describe general aspects of quantum phase transitions, in particular the intriguing interplay of classical and quantum mechanical fluctuations at finite temperatures. The second part will focus on selected examples of quantum phase transitions and make contact to recent experiments, ranging from high-temperature superconductors to topological states of matter. Links to the physics of ultracold atomic gases and to string theory will be discussed as well.

Kontakt: Rainer-G. Ulbrich

A bacterium is the smallest 'quantum' of autonomous living matter. Their physical dimensions mean that they are colloids. But they are 'active colloids' in that they transduce free energy from their environment, and use the energy to engage in intrinsically non-equilibrium activities such as growth and self-propelled motion ('swim'). Until now, the biophysical study of bacteria has concentrated on intra-cellular processes. In this talk, I will introduce an emerging field of biophysics in which the focus of attention is on whole bacterial cells considered as active colloidal particles; experimental methods and theoretical ideas from soft matter physics are then used to give insights into the behaviour of single cells (e.g. how they swim in magnetic fields) and of multiple cells (e.g. the shape of colonies and the mode of aggregation). Experiments using well-characterised bacteria in turn show new phenomena not previously seen in passive colloids. Accounting for these phenomena satisfactorily will need fundamental advances in statistical mechanics.

Kontakt: Rainer-G. Ulbrich

Kontakt: Rainer-G. Ulbrich

Kontakt: Rainer-G. Ulbrich

The speed at which liquid can move over a solid surface is strongly limited when a three-phase contact line is present, separating wet from dry regions. When enforcing large contact line speeds this leads to entrainment of drops, films or air bubbles. In this talk, we discuss experimental and theoretical progress revealing the physical mechanisms behind these dynamical wetting transitions. In this context we discuss microscopic processes that have been proposed to resolve the moving contact line paradox, and identify various dynamical regimes of contact line motion.

Kontakt: Rainer-G. Ulbrich

Kontakt: Rainer-G. Ulbrich

Kontakt: Rainer-G. Ulbrich

Kontakt: Rainer-G. Ulbrich

Kontakt: Rainer-G. Ulbrich

Kontakt: Rainer-G. Ulbrich