Mobility and diffusion of a tagged particle in a driven colloidal suspension
Mobility and diffusion of a tagged particle in a driven colloidal suspension
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标记颗粒在驱动胶体悬浮液中的迁移和扩散
DOI：
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
Thomas Speck
中科院分区：
文献类型：
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作者：
Boris Lander;Udo Seifert;Thomas Speck
我们通过数值研究了密度和应变率对剪切胶体悬浮液中单个标记颗粒的扩散和迁移率的影响。我们独立地确定与时间相关的速度自相关函数，并通过一种新颖的方法确定关于小力的响应函数。虽然扩散系数和迁移率都取决于应变率，但后者表现出相当弱的依赖性。有点令人惊讶的是，我们发现响应和相关函数的初始衰减是一致的，从而可以根据“有效温度”进行解释。这样的唯象有效温度恢复了非平衡状态下的爱因斯坦关系。我们表明，我们的数据可以通过应变率的两次展开到最低阶来很好地描述。
We study numerically the influence of density and strain rate on the diffusion and mobility of a single tagged particle in a sheared colloidal suspension. We determine independently the time-dependent velocity autocorrelation functions and, through a novel method, the response functions with respect to a small force. While both the diffusion coefficient and the mobility depend on the strain rate the latter exhibits a rather weak dependency. Somewhat surprisingly, we find that the initial decay of response and correlation functions coincide, allowing for an interpretation in terms of an “effective temperature”. Such a phenomenological effective temperature recovers the Einstein relation in nonequilibrium. We show that our data is well described by two expansions to lowest order in the strain rate.