English

Detecting and characterizing phase transitions in active matter using entropy

Soft Condensed Matter 2024-07-11 v2 Statistical Mechanics

Abstract

A major challenge in the study of active matter lies in quantitative characterization of phases and transitions between them. We show how the entropy of a collection of active objects can be used to classify regimes and spatial patterns in their collective behavior. Specifically, we estimate the contributions to the total entropy from correlations between the degrees of freedom of position and orientation. This analysis pin-points the flocking transition in the Vicsek model while clarifying the physical mechanism behind the transition. When applied to experiments on swarming Bacillus subtilis with different cell aspect ratios and overall bacterial area fractions, the entropy analysis reveals a rich phase diagram with transitions between qualitatively different swarm statistics. We discuss physical and biological implications of these findings.

Keywords

Cite

@article{arxiv.2304.13679,
  title  = {Detecting and characterizing phase transitions in active matter using entropy},
  author = {Benjamin Sorkin and Avraham Be'er and Haim Diamant and Gil Ariel},
  journal= {arXiv preprint arXiv:2304.13679},
  year   = {2024}
}

Comments

18 pages, 5 figures. arXiv admin note: text overlap with arXiv:2208.05295

R2 v1 2026-06-28T10:18:49.463Z