Phase coexistence far from equilibrium

TL;DR

This paper explores how phase coexistence in simple far-from-equilibrium systems is ill-defined because the properties of coexisting systems depend on contact conditions, challenging traditional notions of universality.

Contribution

It demonstrates that phase coexistence and intrinsic phase properties are not well-defined in far-from-equilibrium systems, contrasting with equilibrium thermodynamics.

Findings

Phase coexistence depends on contact conditions.

Universality of phase coexistence is lost far from equilibrium.

Intrinsic phase properties are environment-dependent.

Abstract

Investigation of simple far-from-equilibrium systems exhibiting phase separation leads to the conclusion that phase coexistence is not well defined in this context. This is because the properties of the coexisting nonequilibrium systems depend on how they are placed in contact, as verified in the driven lattice gas with attractive interactions, and in the two-temperature lattice gas, under (a) weak global exchange between uniform systems, and (b) phase-separated (nonuniform) systems. Thus, far from equilibrium, the notions of universality of phase coexistence (i.e., independence of how systems exchange particles and/or energy), and of phases with intrinsic properties (independent of their environment) are lost.