Unifying descriptions of phase separation in multi-component driven, steady-state systems.

Combined experimental and computational work has shown that a nonequilibrium driven system of Janus particles exhibits phase behavior that is accurately described by the standard Ising model. This suggests that certain steady-state, yet nonequilibrium systems may be described by thermodynamic equilibrium universality classes. Such a description would allow precise control over the phase behavior of active particles, enabling us to design the next generation of active materials analogous to the widespread application of phase separation in creating conventional materials. We examine the generality of this proposition by considering multi-component systems of composite active particles that may belong to other universality classes.