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Nonequilibrium pathways between cluster morphologies in active phase separation: Necking, rupture, and cavitation

Liheng Yao (姚立衡)1,2, Michael E. Cates1, and Robert L. Jack1,3

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Phys. Rev. E 114, 014148 – Published 28 July, 2026

DOI: https://doi.org/10.1103/vdps-lhr9

Abstract

We investigate the dynamical pathways of a morphological transition in a two-dimensional active lattice gas undergoing motility-induced phase separation. The transition is between two locally stable morphologies of the liquid cluster: a system-spanning “slab” and a compact “droplet.” We generate trajectories of this transition in both directions using forward flux sampling. We find that the droplet-to-slab transition always follows a similar mechanism to its equilibrium counterpart, but the reverse (slab-to-droplet) transition depends on rare nonequilibrium fluctuations. At low Péclet numbers the equilibrium and nonequilibrium pathways compete, while at high Péclet numbers the equilibrium pathway is entirely suppressed, and the only allowed mechanism involves a large vapor bubble. We discuss the implications of these findings for active matter systems more generally.

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Controlling Stochastic Dynamics Across Scales

We present a Collection of papers on Controlling Stochastic Dynamics Across Scales. It seeks to highlight novel studies on controlling the dynamics of complex stochastic systems with a rich phenomenology. Guest editors of the Collection are Étienne Fodor of the University of Luxembourg and Todd Gingrich of Northwestern University.

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Information

Phys. Rev. E 114, 014148– Published 28 July, 2026
  • Received 30 December 2025
  • Revised 12 May 2026
  • Accepted 23 June 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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