发表机构
University of Oxford; Queensland University of Technology; Indian Institute of Technology Madras（牛津大学; 昆士兰科技大学; 马德拉斯印度理工学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文解析研究了受限活性向列相中自发流动的起始机制，揭示了长波长与有限波长两种竞争性不稳定性，并确定了有限波长不稳定性在低活性下先导致涡旋产生的条件。
AI 中文摘要
活性向列相在受限几何结构中，当活性超过临界值时可以自发产生流动。我们通过解析方法证明，流动的起始由两种竞争性不稳定性控制：一种长波长模式导致单向流动，另一种有限波长不稳定性产生横向滚转。通过约化描述，我们揭示了活性、流动取向和向列弹性如何控制这些模式之间的竞争。我们确定了有限波长不稳定性具有比长波长不稳定性更低临界活性的区域，导致涡旋在单向流动之前出现。这确立了波长选择作为活性向列相自发流动起始的内在特征。
英文摘要
Active nematics can spontaneously develop flow beyond a critical activity in confined geometries. We show analytically that the onset of flow is governed by two competing instabilities: a long-wavelength mode leading to unidirectional flow and a finite-wavelength instability producing transverse rolls. A reduced description reveals how activity, flow alignment, and nematic elasticity control the competition between these modes. We identify regimes in which the finite-wavelength instability has a lower critical activity than the long-wavelength instability, causing vortices to emerge before unidirectional flow. This establishes wavelength selection as an intrinsic feature of the onset of spontaneous flow in active nematics.
Comments5 pages, 3 figures
