• DOI:10.1103/PhysRevE.101.052601
• Corpus ID: 119178792

Asymmetric exchange in flocks

@inproceedings{Dadhichi2016AsymmetricEI,
  title={Asymmetric exchange in flocks},
  author={Lokrshi Prawar Dadhichi and Rahul Chajwa and Ananyo Maitra and Sriram Ramaswamy},
  year={2016}
}

• Lokrshi Prawar Dadhichi, Rahul Chajwa, +1 author S. Ramaswamy
• Published 3 May 2016
• Physics

As the constituents of a flock are polar, one expects a fore-aft asymmetry in their interactions. We show here that the resulting antisymmetric part of the “exchange coupling” between a bird and its neighbours, if large enough, destabilizes the flock through spontaneous turning of the birds. The same asymmetry also yields a natural mechanism for a difference between the speed of advection of information along the flock and the speed of the flock itself. We show that the absence of detailed balance, and not merely the breaking of Galilean invariance, is responsible for this difference. We delineate the conditions on parameters and wavenumber for the existence of the turning instability. Lastly we present an alternative perspective based on flow-alignment effects in an active liquid crystal with turning inertia in contact with a momentum sink.