Active matter exhibits a wealth of emergent non-equilibrium behaviors. A paradigmatic example is the interior of biological cells. The intimate coupling of active forces, thermal noise, hydrodynamic interactions, and polymeric connectivity implies the emergence of novel structural and dynamical features.
Different propulsion mechanisms capture the physics of active polymeric systems, such as chains of active Brownian particles, and polar tangentially propelled laments. This leads to interesting single-particle behavior, such as a softening of active Brownian laments at intermediate levels of activity. At high polymer densities, collective dynamics is characterized by active turbulence.
Vesicles with internal active components are highly simplifed models of cells. Here, the active components lead to enhanced fluctuations and an intimate coupling of propulsion forces, membrane deformability, cell shape, and cell sensing and reactivity.
In all these systems, computational models of active matter play an essential role to elucidate their non-equilibrium behavior.