@article{200621,
  author = {Jie Zhang and Ricard Alert and Jing Yan and Ned S. Wingreen and Steve Granick},
  title = {Active phase separation by turning towards regions of higher density},
  abstract = { Studies of active matter, from molecular assemblies to animal groups, have revealed two broad classes of behaviour: a tendency to align yields orientational order and collective motion, whereas particle repulsion leads to self-trapping and motility-induced phase separation. Here we report a third class of behaviour: orientational interactions that produce active phase separation. Combining theory and experiments on self-propelled Janus colloids, we show that stronger repulsion on the rear than on the front of these particles produces non-reciprocal torques that reorient particle motion towards high-density regions. Particles thus self-propel towards crowded areas, which leads to phase separation. Clusters remain fluid and exhibit fast particle turnover, in contrast to the jammed clusters that typically arise from self-trapping, and interfaces are sufficiently wide that they span entire clusters. Overall, our work identifies a torque-based mechanism for phase separation in active fluids, and our theory predicts that these orientational interactions yield coexisting phases that lack internal orientational order. },
  year = {2021},
  journal = {Nature Physics},
  volume = {17},
  number = {8},
  pages = {961-967},
  month = {08/2021},
  isbn = {1745-2481},
  language = {eng},
}