Before revision:  Motivated by this we study models with out-of-equilibrium dynamics that depend on the local density. Our simulations suggest that density-dependent dynamics in which the motion of a molecule slows down in the presence of nearby molecules , tend to cause condensation into an out-of-equilibrium liquidstate. This out-of-equilibrium state behaves like a liquid in the sense that it coexists with a much more dilute phase, droplets coalesce, and the state has a well-defined surface tension --- which we calculate. Liquid /liquid separation appears to be a very general phenomenon that occurs in and out of equilibrium .
After revision:  Motivated by this we consider what sort of simple rules for the dynamics of model mRNA molecules lead to liquid /liquid separation appears to be a very general phenomenon that occurs in and out of equilibrium .