Coexistence of defect morphologies in three dimensional active nematics
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arXiv
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| Main Authors: | , , , |
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| Format: | Preprint |
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2023
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| _version_ | 1866912453914263552 |
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| author | Digregorio, Pasquale Rorai, Cecilia Pagonabarraga, Ignacio Toschi, Federico |
| author_facet | Digregorio, Pasquale Rorai, Cecilia Pagonabarraga, Ignacio Toschi, Federico |
| contents | We establish how active stress globally affects the morphology of disclination lines of a three dimensional active nematic liquid crystal under chaotic flow. Thanks to a defect detection algorithm based on the local nematic orientation, we show that activity selects a crossover length scale in between the size of small defect loops and the one of long and tangled defect lines of fractal dimension $2$. This length scale crossover is consistent with the scaling of the average separation between defects as a function of activity. Moreover, on the basis of numerical simulation in a 3D periodic geometry, we show the presence of a network of regular defect loops, contractible onto the $3$-torus, always coexisting with wrapping defect lines. While the length of regular defects scales linearly with the emerging active length scale, it verifies an inverse quadratic dependence for wrapping defects. The shorter the active length scale, the more the defect lines wrap around the periodic boundaries, resulting in extremely long and buckled structures. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2307_10103 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Coexistence of defect morphologies in three dimensional active nematics Digregorio, Pasquale Rorai, Cecilia Pagonabarraga, Ignacio Toschi, Federico Soft Condensed Matter Statistical Mechanics We establish how active stress globally affects the morphology of disclination lines of a three dimensional active nematic liquid crystal under chaotic flow. Thanks to a defect detection algorithm based on the local nematic orientation, we show that activity selects a crossover length scale in between the size of small defect loops and the one of long and tangled defect lines of fractal dimension $2$. This length scale crossover is consistent with the scaling of the average separation between defects as a function of activity. Moreover, on the basis of numerical simulation in a 3D periodic geometry, we show the presence of a network of regular defect loops, contractible onto the $3$-torus, always coexisting with wrapping defect lines. While the length of regular defects scales linearly with the emerging active length scale, it verifies an inverse quadratic dependence for wrapping defects. The shorter the active length scale, the more the defect lines wrap around the periodic boundaries, resulting in extremely long and buckled structures. |
| title | Coexistence of defect morphologies in three dimensional active nematics |
| topic | Soft Condensed Matter Statistical Mechanics |
| url | https://arxiv.org/abs/2307.10103 |