Universal fluctuations of single-particle diffusivity in a quenched environment

Takuma Akimoto, Eli Barkai, Keiji Saitou

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

Local diffusion coefficients in disordered materials such as living cells are highly heterogeneous. We consider finite systems with quenched disorder in order to investigate the effects of sample disorder fluctuations and confinement on single-particle diffusivity. While the system is ergodic in a single disorder realization, the time-averaged mean square displacement depends crucially on the disorder; i.e., the system is ergodic but non-self-averaging. Moreover, we show that the disorder average of the time-averaged mean square displacement decreases with the system size. We find a universal distribution for diffusivity in the sense that the shape of the distribution does not depend on the dimension. Quantifying the degree of the non-self-averaging effect, we show that fluctuations of single-particle diffusivity far exceed the corresponding annealed theory and also find confinement effects. The relevance for experimental situations is also discussed.

Original languageEnglish
Article number180602
JournalPhysical Review Letters
Volume117
Issue number18
DOIs
Publication statusPublished - 2016 Oct 27

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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