Dresden 2026 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 43: Poster: Statistical Physics

DY 43.15: Poster

Mittwoch, 11. März 2026, 15:00–18:00, P5

Dynamics of dense phase separation — •Bibhut Sahoo¹ and Peter Sollich^{1, 2} — ¹Institut für Theoretische Physik, Georg-August-Universität Göttingen, 37077 Göttingen — ²Department of Mathematics, King's College London, London

Phase separation in mixtures is a ubiquitous phenomenon in nature. In dense systems, it involves an intriguing interplay of phase separation dynamics with slowing down due to crowding effects. We investigate such systems by encoding the approach to dynamic arrest in the kinetic coefficient at the level of a continuum description. We predict the phase behaviour of such kinetically constrained multicomponent mixtures, including density and composition of both mobile and arrested phases, using a suitable constrained free energy minimization. We probe the coarsening dynamics numerically and find, for the baseline one-component case, a crossover between two distinct domain growth power laws. For binary mixtures with three equilibrium phases (one gas and two demixed liquids), we see a Warren-like scenario where collective diffusion first leads to gas-liquid phase separation without fractionation, before the mixture components eventually start to demix. Surprisingly, this demixing dynamics is interface-induced, i.e. it begins at the interfaces of the initial gas-liquid domains. We rationalize this by controlled numerical experiments starting from constrained (without demixing) gas-liquid equilibria and by theoretical analysis of the local spinodal growth rates.

Keywords: Phase separation; Constrained kinetics; Conserved dynamics; Coarsening rates