标题： 两点均方位移注记 显示英文标题

标题： Note on two-point mean square displacement

摘要： 当感兴趣的探针分子在容器或聚集体中处于随机运动时，需要依赖所谓的两点均方位移（MSD）测量来提取探针的固有迁移性。 我们讨论了两种版本，分别基于两个探针之间相对向量或距离的时间序列，并总结了它们与标准MSD相比的基本特性。 我们还提出了一种方法，从两点MSD中提取（i）位移统计中的非高斯性以及（ii）探针之间的运动相关性。 结果不仅适用于独立探针，也适用于长聚合物内的分子内探针，这可能有助于量化活细胞核中染色质位点的动力学。 显示英文摘要

摘要： When probe molecules of interest are embedded in a container or aggregate under stochastic motion, one needs to rely on the so-called two-point mean square displacement (MSD) measurement to extract the intrinsic mobility of the probes. We discuss two versions, based on the time series of relative vector or distance between two probes, and summarize their basic properties compared to the standard MSD. We also propose a way to extract (i) the non-Gaussianity in the displacement statistics and (ii) the motional correlation between probes from the two-point MSD. The results are presented not only for independent probes, but also for intramolecular probes within a long polymer, which could be useful in quantifying the dynamics of chromatin loci in living cell nucleus.