论文标题
一个维度的订单传播动力学 - 从动力学密度理论的角度来看单文件扩散和笼子
Order-preserving dynamics in one dimension -- single-file diffusion and caging from the perspective of dynamical density functional theory
论文作者
论文摘要
动态密度功能理论（DDFT）是一个强大的变分框架，仅考虑时间依赖于时间依赖的一体数密度，可以研究胶体的非平衡性能。尽管最近取得了很多成功，但正确地对DDFT中的相互作用系统中的长期动态进行了适当的建模仍然是一个困难的问题，因为丢失了临时或永久性粒子笼的结构信息。在这里，我们通过将其简化为一个干净的一维问题来解决这种笼子的场景，其中粒子是由他们的两个下一个邻居创建的完美笼子自然订购的（在一条线上安排）。特别是，我们基于具有不对称对电势的平衡系统构建DDFT近似，因此相应的一体密度仍然具有粒子阶的足迹。该订单保存动力学（OPD）应用于限制的硬杆系统，除了代表单个粒子的密度曲线的正确的长时间行为外，还可以在系统边界处获得精确的结果。在开放系统中，我们的方法正确地重现了减少的长时间扩散系数和尺寸延伸，这是单文件设置的特征。这些观察不能使用没有粒子顺序的当前DDFT形式进行。
Dynamical density functional theory (DDFT) is a powerful variational framework to study the nonequilibrium properties of colloids by only considering a time-dependent one-body number density. Despite the large number of recent successes, properly modeling the long-time dynamics in interacting systems within DDFT remains a notoriously difficult problem, since structural information, accounting for temporary or permanent particle cages, gets lost. Here we address such a caging scenario by reducing it to a clean one-dimensional problem, where the particles are naturally ordered (arranged on a line) by perfect cages created by their two next neighbors. In particular, we construct a DDFT approximation based on an equilibrium system with an asymmetric pair potential, such that the corresponding one-body densities still carry the footprint of particle order. Applied to a system of confined hard rods, this order-preserving dynamics (OPD) yields exact results at the system boundaries, in addition to the imprinted correct long-time behavior of density profiles representing individual particles. In an open system, our approach correctly reproduces the reduced long-time diffusion coefficient and subdiffusion, characteristic for a single-file setup. These observations cannot be made using current forms of DDFT without particle order.
