20.500.12556/RUL-128557 Topology of three-dimensional active nematic turbulence confined to droplets Active nematics contain topological defects that (under sufficient activity) move, create, and annihilate in a chaotic quasi-steady state, called active turbulence. However, understanding active defects under confinement is an open challenge, especially in three dimensions. Here, we demonstrate the topology of three-dimensional active nematic turbulence under the spherical confinement, using numerical modeling. In such spherical droplets, we show the three-dimensional structure of the topological defects, which, because of closed confinement, emerge in the form of closed loops or surface-to-surface spanning line segments. In the turbulent regime, the defects are shown to be strongly spatially and time varying, with ongoing transformations between positive winding, negative winding, and twisted profiles, and with defect loops of zero and nonzero topological charge. The timeline of the active turbulence is characterized by four types of bulk topology-linked events—breakup, annihilation, coalescence, and crossover of the defects—which we note could be used for the analysis of the active turbulence in different three-dimensional geometries. The turbulent regime is separated by a first-order structural transition from a low activity regime of a steady-state vortex structure and an offset single point defect. We also demonstrate coupling of surface and bulk topological defect dynamics by changing from strong perpendicular to in-plane surface alignment. More generally, this work aims to provide insight into three-dimensional active turbulence, distinctly from the perspective of the topology of the emergent three-dimensional topological defects. soft matter physics active nematics topological defects fizika mehke snovi aktivni nematiki topološki defekti true false true Angleški jezik Slovenski jezik Članek v reviji 2021-07-19 13:51:36 2021-07-19 13:51:37 2022-09-07 04:15:56 0000-00-00 00:00:00 2019 0 0 13 str. iss. 3, art. 031051 Vol. 9 2019 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 538.9 2160-3308 10.1103/PhysRevX.9.031051 3358052 RAZ_Copar_Simon_2019.pdf RAZ_Copar_Simon_2019.pdf 1 D0AD8C38AF7865ADC29857DF7A91C46A b28919942763c70571d0b7ab61cebdd6f117a3dd015702afa5961188ced201e9 e0035860-e887-11eb-a523-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=145329 https://journals.aps.org/prx/abstract/10.1103/PhysRevX.9.031051 0 bbc61c79-e887-11eb-a523-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=145328 Fakulteta za matematiko in fiziko 0 0 0