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arXiv 0904.4524cond-mat.softcond-mat.stat-mech
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随机介质中的慢动力学:从玻璃到局域化转变的交叉

Slow dynamics in random media: Crossover from glass to localization transition

Kang Kim, Kunimasa Miyazaki, Shinji Saito

摘要:

我们使用分子动力学模拟研究了在固定障碍物矩阵中运动的粒子的慢动力学。玻璃化转变点随着障碍物密度的增加而急剧降低。在较高的障碍物密度,移动粒子的动力学定性地从玻璃状到洛伦兹气体状弛豫。这种交叉研究的密度关联函数,非遍历参数,均方位移,和非线性动态磁化率。我们的发现是定性与最近的各种空间异质系统的数值和理论研究的结果是一致的。此外,我们表明,缓慢的动态是令人惊讶的丰富和敏感的障碍配置。特别是,观察到一个特定的配置的重入过渡,虽然它的起源是没有直接联系到类似的预测模式耦合理论的基础上。

英文摘要:

We study slow dynamics of particles moving in a matrix of immobile obstacles using molecular dynamics simulations. The glass transition point decreases drastically as the obstacle density increases. At higher obstacle densities, the dynamics of mobile particles changes qualitatively from glass-like to a Lorentz-gas-like relaxation. This crossover is studied by density correlation functions, nonergodic parameters, mean square displacement, and nonlinear dynamic susceptibility. Our finding is qualitatively consistent with the results of recent numerical and theoretical studies on various spatially heterogeneous systems. Furthermore, we show that slow dynamics is surprisingly rich and sensitive to obstacle configurations. Especially, the reentrant transition is observed for a particular configuration, although its origin is not directly linked to the similar prediction based on mode-coupling theory.

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