Saved in:
| Main Authors: | , , |
|---|---|
| Format: | Preprint |
| Published: |
2024
|
| Subjects: | |
| Online Access: | https://arxiv.org/abs/2406.11465 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1866911920556081152 |
|---|---|
| author | Shinde, Rushikesh Voituriez, Raphaël Callan-Jones, Andrew |
| author_facet | Shinde, Rushikesh Voituriez, Raphaël Callan-Jones, Andrew |
| contents | Biological surfaces, such as developing epithelial tissues, exhibit in-plane polar or nematic order and can be strongly curved. Recently, integer (+1) topological defects have been identified as morphogenetic hotspots in living systems. Yet, while +1 defects in active matter on flat surfaces are well-understood, the general principles governing curved active defects remain unknown. Here, we study the dynamics of integer defects in an extensile or contractile polar fluid on two types of morphogenetically-relevant substrates : (1) a cylinder terminated by a spherical cap, and (2) a bump on an otherwise flat surface. Because the Frank elastic energy on a curved surface generically induces a coupling to $\textit{deviatoric}$ curvature, $\mathcal{D}$ (difference between squared principal curvatures), a +1 defect is induced on both surface types. We find that $\mathcal{D}$ leads to surprising effects including localization of orientation gradients and active flows, and particularly for contractility, to hysteresis and bistability between quiescent and flowing defect states. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2406_11465 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Integer defects, flow localization, and bistability on curved active surfaces Shinde, Rushikesh Voituriez, Raphaël Callan-Jones, Andrew Soft Condensed Matter Biological Physics Biological surfaces, such as developing epithelial tissues, exhibit in-plane polar or nematic order and can be strongly curved. Recently, integer (+1) topological defects have been identified as morphogenetic hotspots in living systems. Yet, while +1 defects in active matter on flat surfaces are well-understood, the general principles governing curved active defects remain unknown. Here, we study the dynamics of integer defects in an extensile or contractile polar fluid on two types of morphogenetically-relevant substrates : (1) a cylinder terminated by a spherical cap, and (2) a bump on an otherwise flat surface. Because the Frank elastic energy on a curved surface generically induces a coupling to $\textit{deviatoric}$ curvature, $\mathcal{D}$ (difference between squared principal curvatures), a +1 defect is induced on both surface types. We find that $\mathcal{D}$ leads to surprising effects including localization of orientation gradients and active flows, and particularly for contractility, to hysteresis and bistability between quiescent and flowing defect states. |
| title | Integer defects, flow localization, and bistability on curved active surfaces |
| topic | Soft Condensed Matter Biological Physics |
| url | https://arxiv.org/abs/2406.11465 |