Random time-scale invariant diffusion and transport coefficients
Random time-scale invariant diffusion and transport coefficients
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DOI：
10.1103/physrevlett.101.058101
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发表时间：
2008-08-01
影响因子：
8.6
通讯作者：
Barkai, E.
中科院分区：
文献类型：
--
作者：
He, Y.;Burov, S.;Barkai, E.
活细胞中mRNA分子和脂质颗粒的单粒子跟踪显示，单个粒子的时间平均均方位移（δ（2））在条上保持随机变量，同时表明粒子运动是亚扩散的。我们研究了连续时间随机游走模型中的这种遍历性破缺，并证明了（δ（2））与相应的系综平均不同。特别是，我们推导出分布的随机变量（δ（2））的波动酒吧。类似地，我们量化了对恒定外场的响应，揭示了爱因斯坦关系的推广。单分子跟踪数据的解释的后果进行了讨论。
Single particle tracking of mRNA molecules and lipid granules in living cells shows that the time averaged mean squared displacement (delta(2)) over bar of individual particles remains a random variable while indicating that the particle motion is subdiffusive. We investigate this type of ergodicity breaking within the continuous time random walk model and show that (delta(2)) over bar differs from the corresponding ensemble average. In particular we derive the distribution for the fluctuations of the random variable (delta(2)) over bar. Similarly we quantify the response to a constant external field, revealing a generalization of the Einstein relation. Consequences for the interpretation of single molecule tracking data are discussed.