From flocking to glassiness in dense disordered polar active matter

• Published in: Communications physics 2024-02, Vol.7 (1), p.57-10, Article 57
• Main Authors: Paoluzzi, Matteo, Levis, Demian, Pagonabarraga, Ignacio
• Format: Article
• Language: English
• Subjects: 639/301/923; 639/766/530; 639/766/530/2795; Glass transition; Long range order; Phase separation; Physics; Physics and Astronomy; Scandals; Tissues
• ISSN: 2399-3650; 2399-3650
• DOI: 10.1038/s42005-024-01551-7

Living materials such as biological tissues or bacterial colonies are collections of heterogeneous entities of different sizes, capable of autonomous motion, and often capable of cooperating. Such a degree of complexity brings to collective motion on large scales. However, how the competition between geometrical frustration, autonomous motion, and the tendency to move cooperatively impact large-scale behavior remains an open question. We implement those three ingredients in a model of active matter and show that the system, in forming migratory patterns, can arrange in bands or develop long-range order, depending on the density of the system. We also show that the active material undergoes a reentrant glass transition triggered by the alignment interaction that typically causes only collective migratory motion. Finally, we observe that polar order destroys active phase separation, producing homogeneous, disordered moving configurations. Active matter is a non-equilibrium system exhibiting collective behaviour and can be used to describe a wide range of biological phenomena from groups of cells to flocks of birds. Here, the authors develop a minimal model for studying the collective behaviours of polar and disordered active materials.