Session T41: Swimming, Motility and Locomotion
2:30 PM–5:42 PM, Wednesday, February 29, 2012
Room: 156B
Sponsoring Unit:
DFD
Chair: Paolo Arratia, University of Pennsylvania
Abstract ID: BAPS.2012.MAR.T41.10
Abstract: T41.00010 : Giant number fluctuations in self-propelled particles without alignment
4:18 PM–4:30 PM
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Abstract 
Authors:
Yaouen Fily
(Syracuse University)
Silke Henkes
(Syracuse University)
M. Cristina Marchetti
(Syracuse University and Syracuse Biomaterials Institute)
Giant number fluctuations are a ubiquitous property of active systems. They were predicted using a generic continuum description of active nematics, and have been observed in simulations of Vicsek-type models and in experiments on vibrated granular layers and swimming bacteria. In all of these systems, there is an alignment interaction among the self-propelled units, either imposed as a rule, or arising from hydrodynamic or other medium-mediated couplings. Here we report numerical evidence of giant number fluctuations in a minimal model of self-propelled disks in two dimensions in the absence of any alignment mechanism. The direction of self-propulsion evolves via rotational diffusion and the particles interact solely via a finite range repulsive soft potential. It can be shown that in this system self propulsion is equivalent to a non Markovian noise whose correlation time is controlled by the amplitude of the orientational noise.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2012.MAR.T41.10