Nikkhou M, Škarabot M, Čopar S, Muševič I
J. Stefan Institute, Jamova 39, SI-1000, Ljubljana, Slovenia.
Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, SI-1000, Ljubljana, Slovenia.
Eur Phys J E Soft Matter. 2016 Oct;39(10):100. doi: 10.1140/epje/i2016-16100-0. Epub 2016 Oct 23.
We study topological defect annihilation on a glass fibre with homeotropic surface anchoring of nematic liquid crystal molecules. The fibre is set parallel to the nematic director of a planar cell with variable thickness and we create pairs of Saturn ring and Saturn anti-ring using the laser tweezers. In thick cells we observe in the whole region of defect separation a Coulomb-like pair attraction with no background force, [Formula: see text] with [Formula: see text]. In cells with thickness comparable to glass fibre diameter, we observe the Coulomb-like attraction only at small separations of the defect pair. For separations larger than the fibre diameter, the pair interaction force is independent of separation. This string-like force is attributed to the formation of defect lines, connecting both monopoles and are indeed visible only on extremely confined fibre, where the fibre diameter is practically equal to the nematic layer thickness. Numerical simulations confirm the formation of defect lines connecting both rings.
我们研究了向列型液晶分子垂直表面锚定在玻璃纤维上时拓扑缺陷的湮灭情况。将该纤维与厚度可变的平面盒中的向列型指向矢平行放置，并用激光镊子产生土星环和反土星环对。在厚盒中，我们在缺陷分离的整个区域观察到类似库仑的对吸引力，且无背景力，[公式：见正文]，其中[公式：见正文]。在厚度与玻璃纤维直径相当的盒中，我们仅在缺陷对的小间距处观察到类似库仑的吸引力。对于大于纤维直径的间距，对相互作用力与间距无关。这种线状力归因于连接两个单极子的缺陷线的形成，并且实际上仅在极其受限的纤维上可见，在那里纤维直径实际上等于向列层厚度。数值模拟证实了连接两个环的缺陷线的形成。
