Binysh Jack, Kos Žiga, Čopar Simon, Ravnik Miha, Alexander Gareth P
Mathematics Institute, Zeeman Building, University of Warwick, Coventry CV4 7AL, United Kingdom.
Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana, Slovenia.
Phys Rev Lett. 2020 Feb 28;124(8):088001. doi: 10.1103/PhysRevLett.124.088001.
We describe the flows and morphological dynamics of topological defect lines and loops in three-dimensional active nematics and show, using theory and numerical modeling, that they are governed by the local profile of the orientational order surrounding the defects. Analyzing a continuous span of defect loop profiles, ranging from radial and tangential twist to wedge ±1/2 profiles, we show that the distinct geometries can drive material flow perpendicular or along the local defect loop segment, whose variation around a closed loop can lead to net loop motion, elongation, or compression of shape, or buckling of the loops. We demonstrate a correlation between local curvature and the local orientational profile of the defect loop, indicating dynamic coupling between geometry and topology. To address the general formation of defect loops in three dimensions, we show their creation via bend instability from different initial elastic distortions.
我们描述了三维活性向列相中拓扑缺陷线和环的流动及形态动力学，并通过理论和数值模拟表明，它们受缺陷周围取向序的局部分布支配。分析从径向和切向扭曲到楔形±1/2分布的连续范围的缺陷环分布，我们表明，不同的几何形状可驱动物质垂直于或沿着局部缺陷环段流动，其在闭环周围的变化可导致环的净运动、伸长或形状压缩，或环的屈曲。我们证明了局部曲率与缺陷环的局部取向分布之间的相关性，表明几何形状与拓扑之间的动态耦合。为了研究三维中缺陷环的一般形成，我们展示了它们通过不同初始弹性畸变的弯曲不稳定性而产生的过程。
