Dresden 2014 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 39: Active Colloids

CPP 39.1: Invited Talk

Thursday, April 3, 2014, 09:30–10:00, ZEU 260

Clustering and phase separation of repulsive self-propelled discs — •Thomas Speck — Institut für Physik, Johannes Gutenberg-Universität Mainz, 55128 Mainz

A striking non-equilibrium phenomenon is the clustering of phoretically propelled colloidal particles due to the interplay of volume exclusion and persistence of motion. I will review recent experimental results and present first steps towards a microscopic theory for active Brownian particles without alignment. Starting from the many-body Smoluchowski equation in two dimensions, an effective evolution equation of the tagged particle density is derived. Even for purely repulsive disks, this equation reveals a dynamical instability corresponding to a mobility-induced phase transition. This instability leads to the phase separation of the suspension into a dilute gas phase of single active particles, and a single large cluster. The analytical results are corroborated by extensive numerical simulations for different repulsive pair potentials.