Non-Equilibrium Phenomena in Nematic Liquid Crystals

在模型液晶系统上进行大尺度分子动力学模拟，研究各种非平衡现象。本文研究了一种淬灭向列液晶的相序动力学，特别强调了拓扑缺陷在平衡过程中的作用。为了创建和研究各向异性玻璃系统，将向列相在其结晶点以下进行快速淬火。将开发算法，使模拟可以在大规模并行机器上有效地运行。如果成功，这项工作将进一步理解复杂流体和各向异性系统中的非平衡现象，并提供流体系统中拓扑缺陷的第一个数值模拟。它还将进一步发展在大规模并行机器上有效运行分子动力学模拟所需的计算方法。这项研究由材料研究和先进科学计算部门共同支持，作为“真实材料计划的计算方法”的一部分，该计划是高性能计算和通信计划的一个组成部分。这项计算研究将集中于了解液晶的特性，例如用于视频显示器的液晶在快速冷却时的特性。在冷却过程中，各种缺陷被冻结在液晶中，影响液晶的性能。这个冷却过程太复杂，无法用分析方法建模，只能用计算分析。因此，这个由材料研究和先进科学计算部门共同资助的项目涉及凝聚态物理学家和计算机科学家。计算工作将在新兴的并行计算机上实现。该研究得到了高性能计算和通信倡议中真实材料计算方法项目的支持。

Large-scale molecular dynamics simulations will be carried out on a model liquid crystal system to study a variety of non-equilibrium phenomena. The phase ordering dynamics of a quenched nematic liquid crystal will be investigated with a special emphasis on the role of the topological defects in the equilibration process. A very rapid quench of a nematic below its crystallization point will be undertaken in an effort to create and study an anisotropic glassy system. Algorithms will be developed so that the simulations can run efficiently on massively parallel machines. If successful, this work will further the understanding of non- equilibrium phenomena in complex fluids and anisotropic systems, as well as providing the first numerical simulations of topological defects in fluid systems. It will also further develop the computational approach required to efficiently run molecular dynamics simulations on massively parallel machines. This research is jointly supported by the Divisions of Materials Research and Advanced Scientific Computing as part of the Computational Approaches to Real Materials Initiative which is a component of the High Performance Computing and Communications Initiative. %%% This computational research will focus on understanding the properties of liquid crystals, such as are used in video displays, when they are rapidly cooled. During the cooling process various defects are frozen into the liquid crystal and affect its properties. This cooling process is too complex to be modeled analytically and is only amenable to computational analysis. Thus, this project, which is jointly funded by the Divisions of Materials Research and Advancd Scientific Computing, involves both condensed matter physicists and computer scientists. The computational work will be implemented on the emerging parallel computers. The research is supported through the Computational Approaches to Real Materials program within the High Performance Computing and Communication Initiative.