MPI-DS Colloquium: Active matter in complex environments

Ordinary materials are "passive" in the sense that their constituents are typically made by inert particles which are subjected to thermal fluctuations, internal interactions and external fields but do not move on their own. Living systems, like schools of fish, swarms of birds, pedestrians and swimming microbes are called "active matter" since they are composed of self-propelled particles. Active matter is intrinsically in nonequilibrium and exhibits a plethora of novel phenomena as revealed by a recent combined effort of statistical theory, computer simulation and real-space experiments. After an introduction on biological and artificial self-propelled particles, the talk will focus on modelling of active Brownian particles. Several phenomena in complex environments are then discussed ranging from an active Mpemba effect and spreading of active polymers in porous media to breathing particles and entropons in active crystals.