Research

Active Matter

Active matter is composed of large numbers of active "agents", each of which consumes energy in order to move or to exert mechanical forces.[1][2] Due to the energy consumption, these systems are intrinsically out of thermal equilibrium. Examples of active matter are schools of fish, flocks of birds, bacteria, artificial self-propelled particles, and self-organising bio-polymers such as microtubules and actin, both of which are part of the cytoskeleton of living cells. Most examples of active matter are biological in origin; however, a great deal of current experimental work is devoted to synthetic systems. Active matter is a relatively new material classification in soft matter: the most extensively studied model, the Vicsek model, dates from 1995.[3]

Research in active matter combines analytical techniques, numerical simulations and experiments. Notable analytical approaches include hydrodynamics,[4] kinetic theory, and non-equilibrium statistical physics. Numerical studies mainly involve self-propelled-particles models,[5][6] making use of agent-based techniques and molecular dynamics algorithms. Experiments on biological systems extend over a wide range of scales, including animal groups (e.g., bird flocks,[7] mammalian herds, fish schools and insect swarms[8]), bacterial colonies, cellular tissues (e.g. epithelial tissue layers,[9] cancer growth and embryogenesis), cytoskeleton components (e.g., in vitro motility assays, actin-myosin networks and molecular-motor driven filaments[10]). Experiments on synthetic systems include self-propelled colloids (e.g., phoretically propelled particles[11]), driven granular matter (e.g. vibrated monolayers[12]), swarming robots and Quinke rotators.

The following research groups in the Max Planck Center work in this topic: