https://doi.org/10.1140/epje/i2020-11934-3
Regular Article
Coarsening dynamics in the Vicsek model of active matter
1
School of Physical Sciences, Jawaharlal Nehru University, 110067, New Delhi, India
2
Laboratoire Charles Coulomb Université Montpellier and CNRS, UMR 5221, 34095, Montpellier, France
3
Department of Physics, Indian Institute of Technology Bombay, 400076, Powai, Mumbai, India
* e-mail: purijnu@gmail.com
Received:
6
December
2019
Accepted:
27
January
2020
Published online:
10
February
2020
We study the flocking model introduced by Vicsek et al. (Phys. Rev. Lett. 75, 1226 (1995)) in the “coarsening” regime. At standard self-propulsion speeds, we find two distinct growth laws for the coupled density and velocity fields. The characteristic length scale of the density domains grows as 
(with 
, while the velocity length scale grows much faster, viz., 
(with 
. The spatial fluctuations in the density and velocity fields are studied by calculating the two-point correlation function and the structure factor, which show deviations from the well-known Porod’s law. This is a natural consequence of scattering from irregular morphologies that dynamically arise in the system. At large values of the scaled wave vector, the scaled structure factors for the density and velocity fields decay with powers -2.6 and -1.52 , respectively.
Key words: Flowing Matter: Active Fluids
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature, 2020
