Aldana M, Dossetti V, Huepe C, Kenkre V M, Larralde H
Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Apartado Postal 48-3, Cuernavaca, Morelos 62251, México.
Phys Rev Lett. 2007 Mar 2;98(9):095702. doi: 10.1103/PhysRevLett.98.095702.
An important characteristic of flocks of birds, schools of fish, and many similar assemblies of self-propelled particles is the emergence of states of collective order in which the particles move in the same direction. When noise is added into the system, the onset of such collective order occurs through a dynamical phase transition controlled by the noise intensity. While originally thought to be continuous, the phase transition has been claimed to be discontinuous on the basis of recently reported numerical evidence. We address this issue by analyzing two representative network models closely related to systems of self-propelled particles. We present analytical as well as numerical results showing that the nature of the phase transition depends crucially on the way in which noise is introduced into the system.
鸟类群体、鱼群以及许多类似的自推进粒子集合体的一个重要特征是出现集体有序状态，即粒子沿相同方向移动。当向系统中添加噪声时，这种集体有序状态的出现是通过由噪声强度控制的动态相变发生的。虽然最初认为是连续的，但根据最近报道的数值证据，有人声称该相变是不连续的。我们通过分析与自推进粒子系统密切相关的两个代表性网络模型来解决这个问题。我们给出的分析和数值结果表明，相变的性质关键取决于将噪声引入系统的方式。
