Time-Average Based on Scaling Law in Anomalous Diffusions

Abstract

To solve the obscureness in measurement brought about from the weak ergodicity breaking appeared in anomalous diffusions we have suggested the time-averaged mean squared displacement (MSD) ${\overline{{\delta }^2(\tau )}}_{\tau }$ with a integral interval depending linearly on the lag time $\tau$. For the continuous time random walk describing a subdiffusive behavior, we have found that ${\overline{{\delta }^2(\tau )}}_{\tau }\sim {\tau }^{\gamma }$ like that of the ensemble-averaged MSD, which makes it be possible to measure the proper exponent values through time-average in experiments like a single molecule tracking. Also we have found that it is originated from the scaling nature of the MSD at a aging time in anomalous diffusion and confirmed them through numerical results of the other microscopic non-Markovian model showing subdiffusions and superdiffusions with the origin of memory enhancement.

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