Direct measurement of shear-induced cross-correlations of Brownian motion.
Direct measurement of shear-induced cross-correlations of Brownian motion.
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DOI：
10.1103/physrevlett.103.230602
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发表时间：
2009-09
影响因子：
8.6
通讯作者：
A. Ziehl;J. Bammert;L. Holzer;C. Wagner;W. Zimmermann
中科院分区：
文献类型：
--
作者：
A. Ziehl;J. Bammert;L. Holzer;C. Wagner;W. Zimmermann
实验和理论研究了垂直和沿流线的粒子波动的剪切引起的相互关系。直接测量微米级珠子的布朗运动，用光学镊子在剪切流细胞中握住，显示出相互关系中强烈的时间不对称性，这是由波动的非正常放大引起的。对单粒子概率分布的补充测量证实了这一行为，并且两者的结果都符合朗格万模型。此外，在两个捕获和流体动力相互作用的粒子的正交随机位移之间检测到剪切诱导的反相关，根据粒子的位置，在时间上具有一个或两个极值。
Shear-induced cross-correlations of particle fluctuations perpendicular and along streamlines are investigated experimentally and theoretically. Direct measurements of the Brownian motion of micron-sized beads, held by optical tweezers in a shear-flow cell, show a strong time asymmetry in the cross-correlation, which is caused by the non-normal amplification of fluctuations. Complementary measurements on the single particle probability distribution substantiate this behavior and both results are consistent with a Langevin model. In addition, a shear-induced anticorrelation between orthogonal random displacements of two trapped and hydrodynamically interacting particles is detected, having one or two extrema in time, depending on the positions of the particles.