Spontaneously ordered motion of self-propelled particles
Spontaneously ordered motion of self-propelled particles
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DOI：
10.1088/0305-4470/30/5/009
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发表时间：
1997-03-07
期刊：
影响因子：
--
通讯作者：
Vicsek, T
中科院分区：
文献类型：
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作者：
Czirok, A;Stanley, HE;Vicsek, T
我们研究了一个生物启发，固有的非平衡模型组成的自推进粒子。在该模型中，粒子以恒定的速度在平面上移动;它们通过在每个时间步选择与其邻居的平均方向相等的速度方向来与其邻居局部相互作用。因此，在消失速度的限制下，模型变得类似于经典XY铁磁体的蒙特卡罗实现。通过大规模的数值模拟表明，与平衡态XY模型不同，在该系统中出现了一个长程有序相，其特征在于非零网dow，phi，出现在一个以临界线为边界的相空间域中，该临界线沿着是序参量的涨落发散的.相应的相图作为两个参数的函数，噪声的振幅η和粒子的平均密度ρ的计算，并发现具有类似于ρ（1/2）的形式η（c）（ρ）。我们还发现，根据类似于h（0.9）的幂律phi，phi作为外部偏置h（场或“风”）的函数进行缩放。在有序相中，系统显示出长程相关波动和1/f噪声。
We study a biologically inspired, inherently non-equilibrium model consisting of self-propelled particles. In the model, particles move on a plane with a velocity of constant magnitude; they locally interact with their neighbours by choosing at each timestep a velocity direction equal to the average direction of their neighbours. Thus, in the limit of vanishing velocities the model becomes analogous to a Monte Carlo realization of the classical XY ferromagnet. We show by large-scale numerical simulations that, unlike in the equilibrium XY model, a long-range ordered phase characterized by non-vanishing net dow, phi, emerges in this system in a phase-space domain bordered by a critical line along which the fluctuations of the order parameter diverge. The corresponding phase diagram as a function of two parameters, the amplitude of noise eta and the average density of the particles rho is calculated and is found to have the form eta(c)(rho) similar to rho(1/2). We also find that phi scales asa function of the external bias h (field or 'wind') according to a power law phi similar to h(0.9). in the ordered phase the system shows long-range correlated fluctuations and 1/f noise.