Bacterial Active Nematics

Dense suspensions of motile rod-shaped bacteria unsurprisingly give rise to active nematics dynamics. This provides a fertile and diverse test ground for the many theoretical works on active nematics, in a refreshing change from the microtubule-kinesin assay introduced by the Dogic group that has somehow taken a dominant position in this corner of physics.

I will recall the theoretical challenges and results underlying the physics of active nematics at the occasion of the modeling of three sets of rather recent experiments results obtained with Japanese and Chinese bacteria:

· long-range 2D nematic order in elongated E. coli cells swimming between two glass plates

· quantitative modeling of nematic ‘turbulence’ occurring at the edge of growing colonies of Serratia cells

· topologically protected edge flows in growing colonies of Paenibacillus Vortex


1. Long-range nematic order and anomalous fluctuations in suspensions of swimming filamentous bacteria, Daiki Nishiguchi, Ken H. Nagai, Hugues Chaté, and Masaki Sano, Phys. Rev. E 95, 020601(R) (2017)

2. Data-driven quantitative modeling of bacterial active nematics, He Li, Xia-qing Shi, Mingji Huang, Xiao Chen, Minfeng Xiao, Chenli Liu, Hugues Chaté, and H. P. Zhang, PNAS 116, 777 (2018)

3. He Li, Xia-qing Shi, Hugues Chaté, and H. P. Zhang, Swarming bacteria form a weakly chiral active liquid with strong edge flows, in preparation.

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