Collective behaviors of active particles in and out of equilibrium
Julien Tailleur (MSC – Université Paris-Diderot)
Active matter describes systems in which individual units dissipate energy to exert forces on their environment. Dissipation and injection of energy are then disconnected at the microscopic scale, driving the system strongly out of equilibrium. This leads to phenomenology markedly different from that of equilibrium physics, such as the emergence of dense phases in the absence of cohesive attractive forces. Nevertheless, for a large class of systems, non-trivial mappings exist between active and passive dynamics. In this talk, I will review the existing work on motility-induced phase separation and discuss its relationship with equilibrium physics. I will then show how a large class of tactic active matter models admit an exact mapping onto equilibrium dynamics at the fluctuating hydrodynamic level.