Lévy walks and generalized stochastic collision models
Lévy walks and generalized stochastic collision models
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Lévy 游走和广义随机碰撞模型
DOI：
10.1103/physreve.56.6355
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发表时间：
1997
影响因子：
2.4
通讯作者：
V. Fleurov
中科院分区：
文献类型：
--
作者：
E. Barkai;V. Fleurov
研究了随机碰撞模型，其中质量为 M 的测试颗粒与另一个质量为 m 的浴颗粒碰撞。如果碰撞之间的时间间隔分布是长尾的，则测试粒子的动量弛豫是代数的。扩散得到增强，超扩散是测试颗粒长时间运动的特征。结果表明，长时间< x 2 (t)> 与质量比ε= m/M 无关。质量比是控制< x 2>～t之前和之后扩散增强的转变时间的重要参数。特别注意 ε 较小的瑞利极限。结果表明，当 ε= 1 时，我们的结果与在 Lévy 步行模型框架内获得的结果相同。
A stochastic collision model is studied in which a test particle of a mass M collides with bath particles of another mass m. If the distribution of time intervals between the collisions is long tailed, the relaxation of momentum of the test particle is algebraic. The diffusion is enhanced and a superdiffusion is characteristic of the test particle motion for long times. It is shown that for long times< x 2 (t)> is independent of the mass ratio ε= m/M. The mass ratio is an important parameter controlling a transition time before which< x 2>∼ t and after which diffusion is enhanced. Special attention is given to the Rayleigh limit where ε is small. It is shown that when ε= 1 our results are identical to those obtained within the framework of the Lévy walk model.