Active fluctuations induce buckling of living surfaces

TL;DR

This paper demonstrates that active tension fluctuations in living tissues can induce stochastic buckling of surfaces, leading to wavelength-specific instabilities despite deterministic stability.

Contribution

It introduces a minimal overdamped surface model incorporating active tension fluctuations as multiplicative noise, revealing a novel buckling mechanism.

Findings

Active fluctuations cause stochastic buckling in stable surfaces.

A non-Markovian theory predicts the instability threshold.

Simulations confirm wavelength selection due to fluctuations.

Abstract

Active tissues exhibit tension fluctuations that are correlated in space and time. We study a minimal overdamped surface model in which such fluctuations enter as a zero-mean, multiplicative modulation of the local surface tension. Although the deterministic elastic dynamics (tension plus bending) stabilizes the flat state for all nonzero wave numbers, we find that sufficiently persistent active fluctuations generate positive ensemble growth rates for a finite band of Fourier modes, leading to stochastic buckling with wavelength selection. A non-Markovian theory based on the Novikov--Furutsu theorem captures the instability threshold and unstable band observed in simulations.