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arXiv 1006.4422cond-mat.stat-mech
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集中硬球老化区的次扩散和间歇动力学涨落

Subdiffusion and intermittent dynamic fluctuations in the aging regime of concentrated hard spheres

Djamel El Masri, Ludovic Berthier, Luca Cipelletti

摘要:

本文用计算机模拟方法研究了大密度准硬球系统的非平衡老化动力学。我们发现,突然淬火到大密度后,弛豫时间最初随着系统的年龄呈指数增长。在一个令人惊讶的大的交叉时间后,系统进入渐近老化制度,其特征在于随着年龄的弛豫时间的线性增加。在这个老化制度,单粒子运动是强烈的非菲克,与均方位移增加subdiffusively,与广泛的,非高斯尾巴的粒子位移的分布。我们发现,该系统的年龄通过时间间歇性的弛豫事件,和这些集体的动态波动的详细的有限大小的分析表明,这些事件并没有跨越整个系统,但仍然在空间上本地化。

英文摘要:

We study the nonequilibrium aging dynamics in a system of quasi-hard spheres at large density by means of computer simulations. We find that, after a sudden quench to large density, the relaxation time initially increases exponentially with the age of the system. After a surprisingly large crossover time, the system enters the asymptotic aging regime characterized by a linear increase of the relaxation time with age. In this aging regime, single particle motion is strongly non-Fickian, with a mean-squared displacement increasing subdiffusively, associated to broad, non-Gaussian tails in the distribution of particle displacements. We find that the system ages through temporally intermittent relaxation events, and a detailed finite size analysis of these collective dynamic fluctuations reveals that these events are not spanning the entire system, but remain spatially localized.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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