Diffusion and velocity autocorrelation at the jamming transition.
Diffusion and velocity autocorrelation at the jamming transition.
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干扰转变时的扩散和速度自相关。
DOI：
10.1103/physreve.81.040301
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
P. Olsson
中科院分区：
文献类型：
--
作者：
P. Olsson
我们进行了数值模拟，以检查粒子扩散在稳定的剪切在一个软盘模型在两个维度和零温度周围的干扰密度。我们发现，扩散常数取决于剪切速率作为D约伽马低于干扰和作为D约gammaqD与qD<1的过渡，并着手将其与速度自相关函数的属性。结果发现，这种相关函数是由两个不同的时间尺度的过程。第一个时间尺度，外部施加的剪切速率的倒数，控制的相关性的指数衰减，而第二个时间尺度，等于逆剪切应力，统治的代数衰减随时间的推移。所获得的qD值与相关函数的这些性质有关。
We perform numerical simulations to examine particle diffusion at steady shear in a soft-disk model in two dimensions and zero temperature around the jamming density. We find that the diffusion constant depends on shear rate as D approximately gamma below jamming and as D approximately gammaqD with qD<1 at the transition and set out to relate this to properties of the velocity autocorrelation function. It is found that this correlation function is governed by two processes with different time scales. The first time scale, the inverse of the externally applied shear rate, controls an exponential decay of the correlations whereas the second time scale, equal to the inverse shear stress, governs an algebraic decay with time. The obtained value of qD is related to these properties of the correlation function.