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The Project Areas - Funding period II
In the second funding period we will maintain the successful structure of our three focused project areas chosen to explore the fascinating variety of Nonequilibrium Collective Dynamics in hard and soft condensed matter:
A - Hard Matter : Nonlinear transport and
quantum optics in semiconductors
B - Soft Matter : Collective dynamics and hydrodynamic interactions in complex fluids
C - Biological Systems : Self-organization and nonlinear waves in active media.
Project area A focuses on collective dynamics in semiconductor nanostructures. On the particle level, we explore, on the one hand, Brownian motion of colloidal quantum dots in a solvent and how it influences the formation of collective electronic states shared between the dots. On the other hand, we use one individual or several spatially fixed quantum dots. A two-dimensional electron system is kept in nonequilibrium and it is of interest how it couples to the electronic states in a single or in several dots. The latter system under lasing conditions creates a wealth of nonlinear dynamic response which one conveniently describes on a coarse-grained level. The treatment of these specific systems is accompanied by more conceptual investigations that concentrate on the coupled electronic transport in random networks and on how the nonequilibrium alters the behavior of quantum systems near criticality.
In project area B we investigate dynamic structure formation in various complex fluid systems. On the particle level, exotic magnetic colloids under the influence of rotating or oscillating magnetic fields are expected to show novel self-assembly in nonequilibrium. Dense colloidal suspensions driven by Poiseuille flow in microchannels exhibit collective dynamic features such as oscillations and stochastic jamming-unjamming events. Using a phenomenological approach, the shear driven dynamics of colloidal disks and disk-rod mixtures is studied where various nonequilibrium patterns should form. Finally, we formulate a bottom-up approach for viscoelastic polymeric networks, where characteristic elements are coupled to each other, and monitor their collective response.
Active media and cell motility are investigated in project area C with special emphasis on their chemical regulation. In a combined experimental and theoretical project, we explore how one can extract the chemotactic response of bacteria from a stochastic analysis of their swimming trajectories with the ultimate goal of understanding collective patterns. We also study gliding myxobacteria, where we will develop realistic models for aggregation and pattern formation both on the particle and continuum level taking into account chemical signaling at cell-cell contact. Actin polymerization inside a cell leads to distinct morpho-dynamics of the cell membrane. It results from the spatio-temporal structure of the actin network considered as a mechano-chemical system. Finally, we study the correlated spatio-temporal patterns of contraction and calcium concentration in protoplasmic droplets based on a reaction-diffusion-advection-mechanics model with the goal to understand their motion.