论文标题
部分可观测时空混沌系统的无模型预测
Aggregation of self-propelled particles with sensitivity to local order
论文作者
论文摘要
我们研究一个自螺旋颗粒（SPP）的系统，在该系统中，根据邻域的比对程度，允许单个颗粒在快速排列和缓慢的非对齐状态之间切换。使用本地顺序参数的阈值对开关进行建模。与干净的SPP系统中发现的有序相比，这种附加属性会导致混合阶段。随着阈值从零增加，我们发现非对准器簇的突然出现。非对准器的簇与持续合并和碎片化的对准器的移动簇共存。对于非对准器的聚类，系统的行为对于低和高全球密度的值似乎非常不同。在低密度状态下，对于阈值的最佳值，最大的非对准器的群体的大小增长到最大值，最大值随粒子总数而变化。但是，在进一步增加阈值时，大小减小。相反，对于高密度状态，初始突然上升之后是巨大的非对准器簇的出现。后者的生长可以表征为连续的渗透过渡。此外，我们发现对准器和非对准器之间的速度差异对于对准器和非对准器的分离是必需的。
We study a system of self-propelled particles (SPPs) in which individual particles are allowed to switch between a fast aligning and a slow nonaligning state depending upon the degree of the alignment in the neighborhood. The switching is modeled using a threshold for the local order parameter. This additional attribute gives rise to a mixed phase, in contrast to the ordered phases found in clean SPP systems. As the threshold is increased from zero, we find the sudden appearance of clusters of nonaligners. Clusters of nonaligners coexist with moving clusters of aligners with continual coalescence and fragmentation. The behavior of the system with respect to the clustering of nonaligners appears to be very different for values of low and high global densities. In the low density regime, for an optimal value of the threshold, the largest cluster of nonaligners grows in size up to a maximum that varies logarithmically with the total number of particles. However, on further increasing the threshold the size decreases. In contrast, for the high density regime, an initial abrupt rise is followed by the appearance of a giant cluster of nonaligners. The latter growth can be characterized as a continuous percolation transition. In addition, we find that the speed differences between aligners and nonaligners is necessary for the segregation of aligners and nonaligners.
