Abstract
Abstract
We study the diffusive dynamics of a system in a nonlinear velocity-dependent frictional environment within a continuous time random walk model. In this model, the motion is governed by a shear-thinning frictional force,
−
γ
0
v
/
[
1
+
(
v
2
/
v
c
2
)
]
μ
(
0
<
μ
⩽
1
), where γ
0 represents the coefficient of static friction and µ is the scaling index. Through analytical and numerical results, we construct a diffusion phase diagram that encompasses different regimes upon variations in parameters γ
0 and µ: normal diffusion; superdiffusion; and hyperdiffusion. These transitions occur because the induced weaker friction enhances the diffusion. With a decrease in the scaling index, we find that the γ
0-dependent exponent of diffusion converges towards the experimental findings for ultracold 87Rb atoms because the strong effective friction arises. The discrepancies between the fractional Lévy kinetics and the experimental findings may be potentially reconciled. We believe that these findings are helpful for analyzing experimental observations of cold atoms diffusing in optical lattices.
Funder
Project of High-level Teachers in Beijing Municipal Universities in the Period of 13th Five-year Plan
National Natural Science Foundation of China
STU Scientific Research Initiation
Cited by
1 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献