How many dissenters does it take to disorder a flock?
Abstract
We consider the effect of introducing a small number of nonaligning agents in a wellformed flock. To this end, we modify a minimal model of active Brownian particles with purely repulsive (excluded volume) forces to introduce an alignment interaction that will be experienced by all the particles except for a small minority of ‘dissenters’. We find that even a very small fraction of dissenters disrupts the flocking state. Strikingly, these motile dissenters are much more effective than an equal number of static obstacles in breaking up the flock. For the studied system sizes we obtain clear evidence of scale invariance at the flockingdisorder transition point and the system can be effectively described with a finitesize scaling formalism. We develop a continuum model for the system which reveals that dissenters act like annealed noise on aligners, with a noise strength that grows with the persistence of the dissenters’ dynamics.
 Publication:

New Journal of Physics
 Pub Date:
 October 2017
 DOI:
 10.1088/13672630/aa8ed7
 arXiv:
 arXiv:1701.05477
 Bibcode:
 2017NJPh...19j3026Y
 Keywords:

 Condensed Matter  Statistical Mechanics;
 Condensed Matter  Soft Condensed Matter;
 Physics  Biological Physics
 EPrint:
 22 pages, 8 figures. Version accepted for publication in New Journal of Physics