Fore-aft asymmetric flocking

Chen Qiu-Shi (1) , Aurelio Patelli (2, 3) , Hugues Chaté (2, 4, 5) , Yu-Qiang Ma (1, 5) , Xia-Qing Shi (5)

1 Ecomaterials and Renewable Energy Research Center, National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093
2 SPHYNX - Systèmes Physiques Hors-équilibre, hYdrodynamique, éNergie et compleXes
3 ISC-CNR Roma
4 CSRC - Beijing Computational Science Research Center [Beijing]
5 University of Science & Technology of China [Suzhou]

We show that fore-aft asymmetry, a generic feature of living organisms and some active matter systems, can have a strong influence on the collective properties of even the simplest flocking models. Specifically, an arbitrarily weak asymmetry favoring front neighbors changes qualitatively the phase diagram of the Vicsek model. A region where many sharp traveling band solutions coexist is present at low noise strength, below the Toner-Tu liquid, at odds with the phase-separation scenario well describing the usual isotropic model. Inside this region, a “banded-liquid” phase with algebraic density distribution coexists with band solutions. Linear stability analysis at the hydrodynamic level suggests that these results are generic and not specific to the Vicsek model.

Domaines: Physique [physics]

Chen Qiu-Shi, Aurelio Patelli, Hugues Chaté, Yu-Qiang Ma, Xia-Qing Shi. Fore-aft asymmetric flocking. Physical Review E , 2017, 96, pp.20601. ⟨10.1103/PhysRevE.96.020601⟩. ⟨cea-01591666⟩