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arXiv 0908.2396cond-mat.stat-mechcond-mat.soft
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粘性液体中的密度标度:从弛豫时间到四点可压缩性

Density scaling in viscous liquids: From relaxation times to four-point susceptibilities

D. Coslovich, C. M. Roland

摘要:

本文对Kob-Andersen Lennard-Jones混合物的四点动态磁化率chi_4(t)随温度T和密度ρ的变化进行了数值计算。在T和rho的相关范围内,chi_4(t)的完全t依赖性以及因此与动态相关体积成比例的chi_4(t)中的最大值对于缩放变量rho^gamma/T为常数的状态点是不变的。材料常数γ的值与系统的弛豫时间τ与ρ ^γ/T的叠加值相同。因此,在密度标度保持不变的情况下,动态相关体积与任何热力学条件下的τ直接相关。最后,我们研究的条件下,密度标度性质有关的压力和能量波动之间的强相关性的存在。

英文摘要:

We present numerical calculations of a four-point dynamic susceptibility, chi_4(t), for the Kob-Andersen Lennard-Jones mixture as a function of temperature T and density rho. Over a relevant range of T and rho, the full t-dependence of chi_4(t) and thus the maximum in chi_4(t), which is proportional to the dynamic correlation volume, are invariant for state points for which the scaling variable rho^gamma/T is constant. The value of the material constant gamma is the same as that which superposes the relaxation time, tau, of the system versus rho^gamma/T. Thus, the dynamic correlation volume is directly related to tau for any thermodynamic condition in the regime where density scaling holds. Finally, we examine the conditions under which the density scaling properties are related to the existence of strong correlations between pressure and energy fluctuations.

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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