Long-range nematic order and anomalous fluctuations in suspensions of swimming filamentous bacteria

Daiki H Nishiguchi (1) , Ken H Nagai (2) , Hugues H Chaté (3, 4) , Masaki H Sano (1)

1 UTokyo - The University of Tokyo
2 JAIST - Japan Advanced Institute of Science and Technology
3 CSRC - Beijing Computational Science Research Center [Beijing]
4 SPHYNX - Systèmes Physiques Hors-équilibre, hYdrodynamique, éNergie et compleXes

We study the collective dynamics of elongated swimmers in a very thin fluid layer by devising long, filamentous, non-tumbling bacteria. The strong confinement induces weak nematic alignment upon collision, which, for large enough density of cells, gives rise to global nematic order. This homogeneous but fluctuating phase, observed on the largest experimentally-accessible scale of millimeters, exhibits the properties predicted by standard models for flocking such as the Vicsek-style model of polar particles with nematic alignment: true long-range nematic order and non-trivial giant number fluctuations

Domaines: Physique [physics]

Daiki H Nishiguchi, Ken H Nagai, Hugues H Chaté, Masaki H Sano. Long-range nematic order and anomalous fluctuations in suspensions of swimming filamentous bacteria. Physical Review E , 2017, 95, ⟨10.1103/PhysRevE.95.020601⟩. ⟨cea-01483961⟩