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Accueil > Français > Production scientifique > Séminaire

Clues to understand the collective organisation of self-propelled particles.

par Caroline CHAMPENOIS - publié le

mercredi 15 janvier à 10h30,en salle du conseil de PIIM service 322.

Luciano H. Miranda F.
univ. fed. rur. Pernambuco, Brésil

Abstract :

Active matter is the term designated for agents with their own motive power. Living systems constitute the preeminent example, exhibiting a rich variety of behaviours, including flock dynamics. The paradigmatic Vicsek model is possi-bly the simplest description for flock manifestations. The model describes the transition between organised and non-organised phases, based on self-propelled particles in periodic boundary conditions, with constant speed in the presence of a noise that competes with alignment mechanism included in the model.

Studies are in progress and involve the introduction of some ingredients to the original Vicsek model, in particular an orientational external field. We found that a time-independent field can work as a potential barrier as well as guide the particles, emulating physical gradients. An oscillating field, on the other hand, can aggregate the particles within some characteristic time. The main idea is to discover how these additional rules affect characteristic quantities of the problem and how they could be used to guide, aggregate or dissipate a flock. Traffic jamming, panic evacuation situations and dispersion of animals located in risk areas are examples of problems in which we could discuss based on this proposal.

[1] T. Vicsek, A. Czirok, E. Ben-Jacob, I. Cohen and O. Shochet, Novel Type of Phase Transition in a System of Self-Driven Particles, Phys. Rev. Lett. 75 (1995) 1226–1229.
[2] Israr Ahmed, Dung Q. Ly and Waqar Ahmed, Collective Behavior of Self-propelled Particles in the presence of moving obstacles, Mater. Today : Proceedings 4 (2017) 65–74.
[3] Francesco Ginelli, The Physics of the Vicsek model, Eur. Phys. J. Special Topics 225 (2016) 2099-2117.

contact : Yves Elskens

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