第22回 北大MMCセミナー Collective dynamics of self-propelled soft particles

開催日時
2014年   3月 6日 14時 30分 ~ 2014年   3月 6日 16時 00分
場所
電子科学研究所中央キャンパス総合研究棟2号館 5F講義室 北(北12条西7丁目)
講演者
太田 隆夫(京都大学名誉教授)
 
Abstract:

Dynamics of interacting self-propelled objects has attracted much attention recently from the view point of nonlinear science and nonequilibrium statistical physics [1]. One of the characteristic features of collective dynamics is that homogeneous ordered state where all the particles are traveling coherently to a certain direction at a constant velocity becomes unstable near the order-disorder transition point and traveling bands appear in the matrix of the disordered state [2].

In my talk, I will describe our recent study of interacting self-propelled soft particles whose migration velocity increases with increasing local density [3]. By the word “soft”, I mean that particles are deformable. This is motivated by the fact that there is a coupling between the velocity of the center of mass and shape deformation in the motion of a living cell. Numerical simulations in two dimensions reveal that traveling bands similar to those found previously in the Vicsek-type model are easily formed by this local density dependence of the migration velocity.

We show that a pair of stripe bands which are traveling to the opposite direction is not destructed by a head-on collision but survives again after collision. This soliton-like behavior has also been observed quite recently in density waves in non-chemotactic Dictyostelium discoideum mutants [4]. Similarity to and difference from the experimental results are discussed [5].

[1] T. Vicsek and A. Zafeiris, Phys. Rep. 517, 71 (2012).

[2] H. Chate, F. Ginelli, G. Gregoire, and F. Raynaud, Phys. Rev. E 77, 046113 (2008).

[3] S. Yamanaka and T. Ohta, Phys. Rev. E89 021918 (2014).

[4] H. Kuwayama and S. Ishida, Sci. Rep. 3, 2272; DOI:10.1038/srep02272 (2013).

[5] T. Ohta and S. Yamanaka, Prog. Theor. Exp. Phys. 2014 011J01 (2014).

ポスター第22回北大MMCセミナー2014.3.6太田

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研究集会・セミナー・集中講義の一覧へ