Mesoscopic theory for fluctuating active nematics
Abstract
The term active nematics designates systems in which apolar elongated particles spend energy to move randomly along their axis and interact by inelastic collisions in the presence of noise. Starting from a simple Vicsek-style model for active nematics, we derive a mesoscopic theory, complete with effective multiplicative noise terms, using a combination of kinetic theory and It\^o calculus approaches. The stochastic partial differential equations thus obtained are shown to recover the key terms argued in EPL \textbf{62} (2003) 196 to be at the origin of anomalous number fluctuations and long-range correlations. Their deterministic part is studied analytically, and is shown to give rise to the long-wavelength instability at onset of nematic order (see arXiv:1011.5408). The corresponding nonlinear density-segregated band solution is given in a closed form.
Cite
@article{arxiv.1305.0772,
title = {Mesoscopic theory for fluctuating active nematics},
author = {Eric Bertin and Hugues Chaté and Francesco Ginelli and Shradha Mishra and Anton Peshkov and Sriram Ramaswamy},
journal= {arXiv preprint arXiv:1305.0772},
year = {2014}
}
Comments
24 pages, 1 figure, submitted to New. J. Phys