[23p-E201-1~6] Topological Materials Science for Creation of Innovative Functions

[23p-E201-5] Direct 3D observation of topological defect dynamics in liquid crystal and spontaneous symmetry restoring

〇Kazumasa A. Takeuchi¹, Yohei Zushi¹ (1.Univ. Tokyo)

Keywords:liquid crystal, topological defect

Topological defects -locations of local mismatch of order- constitute a generic concept in physics that abounds in a wide variety of systems. Among them, liquid crystal is interesting for its wide range of applications and amenability to direct optical observations, yet it has been a challenge to resolve three-dimensional structures of dynamically evolving topological defects, especially for their simplest and most important kind, namely nematic disclination lines. Here we report such a direct observation of 3D disclination dynamics, by means of confocal microscopy and dye accumulation at defects. Focusing on reconnections, we characterize disclination dynamics in terms of scaling and asymmetry. Unexpectedly, we find that the asymmetry known to exist in 2D dynamics disappears in 3D. We argue, with experimental supports, that this is because of symmetric twist configurations that disclinations take spontaneously, thanks to the topology that allows continuous change of configuration only in 3D. We also give some perspectives related to turbulence made of such disclinations, which is of interest from both fundamental and application viewpoints.