受限三维活性向列相的拓扑离域化
Topological delocalisation of confined 3D active nematics
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中文总结 AI 辅助
研究三维活性向列相在封闭圆柱体内的受限情况，揭示被动弹性与活性竞争，改变边界曲率等参数得到不同局部化状态，发现受限改变活性标度性质，确立非均匀曲率受限是控制活性拓扑动力学的通用机制。
中文摘要 AI 辅助
三维活性向列相系统中的缺陷线是有趣的拓扑奇点，其非平衡动力学在受限环境中仍难以捉摸。在此，我们通过数值研究封闭圆柱体内的三维活性向列相，以阐明几何形状和活性的作用。我们揭示了被动弹性（使缺陷在边缘附近局部化）与活性（赋予缺陷运动性并导致无序、离域化动力学）之间的竞争。改变边界曲率、活性强度和圆柱半径揭示了静态和动态局部化状态的状态空间。随着活性被调整以诱导离域化，我们识别出相变特征。我们发现这些标度性质因受限而强烈改变，与体系统中活性控制长度分布不同，受限调节一个与活性无关的特征长度，其指数让人联想到自回避受限聚合物。这些结果确立了非均匀曲率的受限作为控制活性拓扑动力学的通用机制。
英文摘要
Defect lines in 3D active nematic systems are intriguing topological singularities whose out-of-equilibrium dynamics remain elusive in confined settings. Here, we numerically study 3D active nematics confined within closed cylinders to elucidate the roles of geometry and activity. We reveal a competition between passive elasticity, which causes localisation of defects near edges, and activity, which endows defects with motility and gives rise to disorderly, delocalised dynamics. Varying boundary curvature, activity strength, and cylinder radius reveals a state space of static and dynamic localisation states, including handle-like configurations and chaotic motion bounded within the cylinder endcap. As activity is tuned to induce delocalisation, we identify phase transition signatures, including pronounced fluctuations and an emergent power law scaling of defect number and average defect length. We find that these scaling properties are strongly altered by confinement: unlike in bulk systems where activity governs length distributions, confinement tunes an activity-independent characteristic length, with an exponent reminiscent of self-avoiding confined polymers. These results establish confinement of inhomogeneous curvature as a versatile mechanism for controlling active topological dynamics.
