AI 中文总结
研究颗粒悬浮液的粒子尺度结构，通过朗之万动力学模拟并与基于平衡的有理函数近似（RFA）比较，发现RFA能很好描述短程和中程结构，在非弹性状态下比珀库斯-耶维克近似更好，为相关模型提供了准确描述。
AI 中文摘要
颗粒悬浮液是本质上的非平衡系统，其中耗散的颗粒-颗粒碰撞与溶剂诱导的驱动力共存。我们研究了由浸没在热浴中的非弹性硬球建模的颗粒悬浮液的粒子尺度结构，并将径向分布函数\(g(r)\)和静态结构因子\(S(q)\)的朗之万动力学模拟结果与基于平衡的有理函数近似（RFA）的预测进行比较。平衡硬球RFA通过接触值和类似等温压缩率的量的非平衡输入得到拉普拉斯空间中\(g(r)\)和\(S(q)\)的解析表达式。我们发现，在广泛的密度、阻力系数和非弹性范围内，RFA对悬浮液的短程和中程结构给出了很好的描述。在非弹性状态下，它比珀库斯-耶维克近似能更好地再现\(g(r)\)，特别是在接触附近，并且除了最小波数外，对\(S(q)\)也有很好的描述。在最小波数处，模拟显示出比RFA预测更强的与阻力相关的增强，表明除了当前类似平衡的描述之外，还有额外的长波长非平衡相关性。这些结果表明，基于平衡的硬球方法对具有非弹性硬球的当前朗之万模型的粒子尺度结构提供了准确的描述（除了最小\(q\)区域），并表明类似的基于平衡的方法可能对相关的非平衡硬球悬浮液模型也有用，包括多组分系统。
英文摘要
Granular suspensions are intrinsically nonequilibrium systems in which dissipative grain-grain collisions coexist with solvent-induced forcing. We study the particle-scale structure of a granular suspension modeled by inelastic hard spheres immersed in a thermal bath and compare Langevin-dynamics simulation results for the radial distribution function $g(r)$ and the static structure factor $S(q)$ with predictions of an equilibrium-inspired rational function approximation (RFA). The equilibrium hard-sphere RFA is supplied with nonequilibrium input for the contact value and a reduced isothermal-compressibility-like quantity, yielding analytical expressions for $g(r)$ in Laplace space and for $S(q)$. We find that the RFA gives a very good description of the short- and intermediate-range structure of the suspension over a broad range of densities, drag coefficients, and inelasticities. It reproduces $g(r)$ substantially better than the Percus-Yevick approximation in inelastic states, especially near contact, and gives a good account of $S(q)$ except at the smallest wave numbers. There, simulations show a drag-dependent enhancement over the RFA prediction, indicating additional long-wavelength nonequilibrium correlations beyond the present equilibrium-like description. These results show that an equilibrium-based hard-sphere approach provides an accurate description of the particle-scale structure of the present Langevin model with inelastic hard spheres (except in the smallest-$q$ region), and suggest that similar equilibrium-inspired approaches may also be useful for related nonequilibrium hard-sphere suspension models, including multicomponent systems.
Comments11 pages, 6 figures. Replacement to resolve rendering issues of the figures in some PDF viewers
