Phase transitions and phase coexistence: equilibrium systems versus externally driven or active systems - Some perspectives

A tutorial introduction to the statistical mechanics of phase transitions and coexistence is presented, starting out from equilibrium systems nonequilibrium steady-state situations in externally driven systems, such as unmixing sheared binary fluid mixtures, lattice gas model, onset Rayleigh-Bénard convection. Then, some models for separation active where particles possess internal motility, are discussed, emphasizing what one can learn by extending analysis methods study computer simulations systems. Specific examples will include colloid-polymer mixtures colloids assumed be particles, Brownian particles. The extent which concepts familiar still useful critically discussed.