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arXiv 1701.00263cond-mat.stat-mechcond-mat.soft
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二元硬球混合物的布居退火模拟

Population Annealing Simulations of a Binary Hard Sphere Mixture

Jared Callaham, Jon Machta

摘要:

布居退火是一种序贯蒙特卡罗方法,非常适合于模拟具有粗糙自由能景观的系统的平衡态。在这里,我们使用人口退火研究硬球的二元混合物。群体退火是模拟退火的并行版本,具有额外的恢复步骤,其确保系统的副本群体表示退火时间表中每个填充分数处的平衡系综。该算法及其平衡性能的描述和结果,提出了一个玻璃形成流体组成的硬球的直径比为1.4:1的50/50的混合物。对于这个系统,我们得到精确的结果,在玻璃态下的状态方程的包装分数$φ\approx 0.60$和研究偏差从BMCSL状态方程。对于更高的填充分数,该算法失去平衡,并且自由体积拟合预测填充分数$φ\approx 0.667$处的堵塞。我们的结论是,布居退火是一个有效的工具,研究平衡玻璃态流体和堵塞过渡。

英文摘要:

Population annealing is a sequential Monte Carlo scheme well-suited to simulating equilibrium states of systems with rough free energy landscapes. Here we use population annealing to study a binary mixture of hard spheres. Population annealing is a parallel version of simulated annealing with an extra resampling step that ensures that a population of replicas of the system represents the equilibrium ensemble at every packing fraction in an annealing schedule. The algorithm and its equilibration properties are described and results are presented for a glass-forming fluid composed of a 50/50 mixture of hard spheres with diameter ratio of 1.4:1. For this system, we obtain precise results for the equation of state in the glassy regime up to packing fractions $φ\approx 0.60$ and study deviations from the BMCSL equation of state. For higher packing fractions, the algorithm falls out of equilibrium and a free volume fit predicts jamming at packing fraction $φ\approx 0.667$. We conclude that population annealing is an effective tool for studying equilibrium glassy fluids and the jamming transition.

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