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Noah Ziethen

@nziethen.bsky.social

Postdoctoral researcher in theoretical physics, curious about living and active matter.

33 Followers  |  68 Following  |  5 Posts  |  Joined: 20.11.2024
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Posts by Noah Ziethen (@nziethen.bsky.social)

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New preprint πŸ₯³
In our new paper, we show that β€œAdvection selects pattern in multi-stable emulsions of active droplets” β€” which provides a path toward controlling regular arrangements of droplets. 🧡
πŸ“„ arxiv.org/abs/2510.00827

02.10.2025 12:35 β€” πŸ‘ 3    πŸ” 1    πŸ’¬ 1    πŸ“Œ 2
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Chemically Active Liquid Bridges Generate Repulsive Forces Droplets help organize cells by compartmentalizing biomolecules and by mediating mechanical interactions. When bridging two structures, such droplets generate capillary forces, which depend on surface...

Many thanks to Frieder Johannsen and the @zwicker-group!
πŸ“„ arxiv.org/abs/2509.18777

29.09.2025 17:19 β€” πŸ‘ 0    πŸ” 0    πŸ’¬ 0    πŸ“Œ 0

πŸ”¬ Cells use droplets to organize their interior, sometimes forming liquid bridges between intracellular structures.
While passive bridges attract, we show that activity can make them repel. Cells might use this to control organelle placement & morphology.

29.09.2025 17:19 β€” πŸ‘ 0    πŸ” 0    πŸ’¬ 1    πŸ“Œ 0
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By combining the fixed bridge radius with a thin-interface approximation, we derived an analytic force expression for a cylindrical active bridge.
β€¨βœ… It matches the scaling found in simulationsβ€”showing that size control is the main driver of the observed effects.

29.09.2025 17:18 β€” πŸ‘ 1    πŸ” 0    πŸ’¬ 1    πŸ“Œ 0
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Why?
Passive: Stretching increases surface energy, pulling walls together
Active: Chemical reactions maintain fixed bridge radius regardless of wall separation
πŸ‘‰ The bridge doesn't thin but can grow in volume β†’ it is energetically favorable for the walls to move apart, generating repulsion.

29.09.2025 17:17 β€” πŸ‘ 1    πŸ” 0    πŸ’¬ 1    πŸ“Œ 0
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New preprint πŸŽ‰
What began as Frieder Johannsen’s bachelor thesis in the @zwickergroup.bsky.social (which I had the pleasure to supervise) evolved into our latest paper: β€œChemically Active Liquid Bridges Generate Repulsive Forces” β€” unlike passive ones, which attract.
πŸ“„ arxiv.org/abs/2509.18777

29.09.2025 17:17 β€” πŸ‘ 11    πŸ” 3    πŸ’¬ 1    πŸ“Œ 1