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arXiv 1707.07076cond-mat.softcond-mat.stat-mech
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二元混合物的有效单组分模型:空间相关随机动力学诱导的分子阻滞

Effective one-component model of binary mixture: molecular arrest induced by the spatially correlated stochastic dynamics

M. Majka, P. F. Góra

摘要:

空间相关噪声(SCN),即以类似方式影响相邻粒子的热噪声,在软物质系统中普遍存在。在这项工作中,我们应用过阻尼SCN驱动的朗之万方程作为一个有效的,单组分模型的动态在稠密的二元混合物。我们推导出SCN的一致性波动耗散关系,表明它预测类似于玻璃化转变的分子停滞,即在无序相的动力学临界减速。我们发现,奇异耗散的机制是嵌入在耗散矩阵,伴随SCN。我们还能够确定的特征长度的集体耗散,发散在临界包装。这个新的物理量方便地描述了遍历和非遍历动力学之间的差异。该模型是完全解析可解的、一维的,并且允许粒子之间的任意相互作用。它定性地再现了在二元混合物中遇到的几种不同的被捕障碍模式,包括例如再入逮捕。该模型可以有效地与模式耦合理论进行比较。

英文摘要:

Spatially correlated noise (SCN), i.e. the thermal noise that affects neighbouring particles in a similar manner, is ubiquitous in soft matter systems. In this work, we apply the over-damped SCN-driven Langevin equations as an effective, one-component model of the dynamics in dense binary mixtures. We derive the thermodynamically consistent fluctuation-dissipation relation for SCN to show that it predicts the molecular arrest resembling the glass transition, i.e. the critical slow-down of dynamics in the disordered phases. We show that the mechanism of singular dissipation is embedded in the dissipation matrix, accompanying SCN. We are also able to identify the characteristic length of collective dissipation, which diverges at critical packing. This novel physical quantity conveniently describes the difference between the ergodic and non-ergodic dynamics. The model is fully analytically solvable, one-dimensional and admits arbitrary interactions between the particles. It qualitatively reproduces several different modes of arrested disorder encountered in binary mixtures, including e.g. the re-entrant arrest. The model can be effectively compared to the mode coupling theory.

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