de Nigris Sarah, Carletti Timoteo, Lambiotte Renaud
naXys, Namur Center for Complex Systems, UNamur, 5000, Namur, Belgium.
Univ Lyon, Cnrs, ENS de Lyon, Inria, UCB Lyon 1, LIP UMR 5668, 69342, Lyon, France.
Phys Rev E. 2017 Feb;95(2-1):022113. doi: 10.1103/PhysRevE.95.022113. Epub 2017 Feb 13.
Anomalous diffusion processes, in particular superdiffusive ones, are known to be efficient strategies for searching and navigation in animals and also in human mobility. One way to create such regimes are Lévy flights, where the walkers are allowed to perform jumps, the "flights," that can eventually be very long as their length distribution is asymptotically power-law distributed. In our work, we present a model in which walkers are allowed to perform, on a one-dimensional lattice, "cascades" of n unitary steps instead of one jump of a randomly generated length, as in the Lévy case, where n is drawn from a cascade distribution p_{n}. We show that this local mechanism may give rise to superdiffusion or normal diffusion when p_{n} is distributed as a power law. We also introduce waiting times that are power-law distributed as well and therefore the probability distribution scaling is steered by the two local distributions power-law exponents. As a perspective, our approach may engender a possible generalization of anomalous diffusion in context where distances are difficult to define, as in the case of complex networks, and also provide an interesting model for diffusion in temporal networks.
反常扩散过程,特别是超扩散过程,被认为是动物搜索和导航以及人类移动性中的有效策略。产生这种机制的一种方法是 Lévy 飞行,即行走者被允许进行跳跃,也就是“飞行”,由于其长度分布渐近地服从幂律分布,所以这些跳跃最终可能会非常长。在我们的工作中,我们提出了一个模型,在该模型中,行走者被允许在一维晶格上执行 n 个单位步长的“级联”,而不是像 Lévy 情况那样进行随机生成长度的一次跳跃,其中 n 是从级联分布 p_n 中抽取的。我们表明,当 p_n 按幂律分布时,这种局部机制可能会导致超扩散或正常扩散。我们还引入了同样按幂律分布的等待时间,因此概率分布的标度由两个局部分布的幂律指数控制。从一个角度来看,我们的方法可能会在距离难以定义的情况下,如复杂网络的情况,对反常扩散进行可能的推广,并且还为时间网络中的扩散提供一个有趣的模型。