论文标题
忽略多分散性降低了超冷液体中的倾向测量
Neglecting polydispersity degrades propensity measurements in supercooled liquids
论文作者
论文摘要
我们对以前的Bidisperseperse kob-Andersen（Ka）玻璃进行了分子动力学模拟，以添加其他多分散性。已知原始的KA系统表现出动态异质性。先前的工作定义了倾向，粒子的平均运动平均在模拟上平均重建所有粒子的初始位置，但具有随机速度。倾向的存在表明结构和动力学已连接。在本文中，我们研究了在测量胶体玻璃中倾向的倾向时会遇到的系统，该系统是粒子是多分散的（它们的大小变化）。我们通过将bidisperseka系统更改为四重奏组成的四重奏组成，该四重奏组成的四重奏组成，该四重奏由比原始bidisperse系统中的母体颗粒稍大且稍小。然后，我们将误差引入重建初始位置的重建，以模仿人们在胶体实验中可能犯的错误。这些错误降低了倾向测量，在某些情况下几乎完全是完全的。一个人在任何有用的意义上都不再具有异位配合。我们的结果表明，多分散样品适用于倾向测量，只要避免重建错误。
We conduct molecular dynamics simulations of a bidisperse Kob-Andersen (KA) glass former, modified to add in additional polydispersity. The original KA system is known to exhibit dynamical heterogeneity. Prior work defined propensity, the mean motion of a particle averaged over simulations reconstructing the initial positions of all particles but with randomized velocities. The existence of propensity shows that structure and dynamics are connected. In this paper, we study systems which mimic problems that would be encountered in measuring propensity in a colloidal glass former, where particles are polydisperse (they have slight size variations). We mimic polydispersity by altering the bidisperse KA system into a quartet consisting of particles both slightly larger and slightly smaller than the parent particles in the original bidisperse system. We then introduce errors into the reconstruction of the initial positions that mimic mistakes one might make in a colloidal experiment. The mistakes degrade the propensity measurement, in some cases nearly completely; one no longer has an isoconfigurational ensemble in any useful sense. Our results show that a polydisperse sample is suitable for propensity measurements provided one avoids reconstruction mistakes.
