arXiv subjects

H Chate

Publications and source records attributed to H Chate.

2 recordsLinked to original sources

arXiv2004

Onset of collective and cohesive motion

We study the onset of collective motion, with and without cohesion, of groups of noisy self-propelled particles interacting locally. We find that this phase transition, in two space dimensions, is always discontinuous, including for the minimal model of Vicsek et al. [Phys. Rev. Lett. {\bf 75},1226 (1995)] for which a non-trivial critical point was previously advocated. We also show that cohesion is always lost near onset, as a result of the interplay of density, velocity, and shape fluctuations.

cond-mat.stat-mech↗

arXiv1998

Phase Coherence in Chaotic Oscillatory Media

Collective oscillations of lattices of locally-coupled chaotic Roessler oscillators are studied with regard to the dynamical scaling of their phase interfaces. Using analogies with the complex Ginzburg-Landau and the Kardar-Parisi-Zhang equations, we argue that phase coherence should be lost in the infinite-size limit. Our numerical results, however, indicate possible discrepancies with a Langevin-like description using an effective white-noise term.

chao-dyn↗