Model AB -- a canonical model for phase-separating non-equilibrium systems with chemical reactions

28 Aug 2019 - Irene

Active matter, characterised by their ability to inject energy into the environment locally, forms an important class of non-equilibrium systems. Recently there has been a surge of interests in active systems with chemical reactions, fuelled in particular by studies in biomolecular condensates, or ‘membraneless organelles’, within cells. In contrast to their passive coun- terparts, such systems have conserved and non-conserved dynamics that do not, in general, derive from a shared free energy. This mismatch breaks time-reversal symmetry (TRS) and leads to new types of dynamical competition that are absent in or near equilibrium. We construct a canonical scalar field theory to describe such systems, with conserved and non- conserved dynamics obeying Model B and Model A respectively (in the Hohenberg-Halperin classification), chosen such that the two free energies involved are incompatible. The resulting minimal model is shown to capture the various phenomenologies reported previously for more complicated models with the same physical ingredients, including microphase separation, limit cycles and droplet splitting. For further details, see my paper on Model AB.

This is a poster I made on this project: get the PDF