{"ID":23673044,"CreatedAt":"2026-09-18T08:32:08.518820066Z","UpdatedAt":"2026-09-18T08:32:08.518820066Z","DeletedAt":null,"paper_url":"https://arxiv.org/abs/2609.20786","arxiv_id":"2609.20786","title":"Competing routes to spontaneous flow in confined active nematics","abstract":"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.","short_abstract":"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 descri...","url_abs":"https://arxiv.org/abs/2609.20786","url_pdf":"https://arxiv.org/pdf/2609.20786v1","authors":"[\"Rahil N. Valani\",\"Vedad Dzanic\",\"Sumesh P. Thampi\",\"Julia M. Yeomans\"]","published":"2026-09-17T17:52:24Z","proceeding":"cond-mat.soft","tasks":"[\"cond-mat.soft\"]","methods":"[]","has_code":false}