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arXiv · 2401.15658

Non-Equilibrium Fluidization of Dense Active Suspension

Yujiro Sugino·Hiroyuki Ebata·Yoshiyuki Sowa·Atsushi Ikeda·Daisuke Mizuno
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Abstract

We investigate dense suspensions of swimming bacteria prepared in a nutrient-exchange chamber. Near the pellet concentration, nonthermal fluctuations showed notable agreement between self and collective behaviors, a phenomenon not previously observed at equilibrium. The viscosity of active suspensions dramatically decreased compared to their inactive counterparts, where glassy features, such as non-Newtonian viscosity and dynamic heterogeneity, disappeared. Instead, the complex shear modulus showed a power-law rheology,$G^*(\omega)\propto\left(-i\omega\right)^\frac{1}{2}$, indicating the role of bacterial activity in driving the system towards a critical jamming state.

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Yujiro Sugino, Hiroyuki Ebata, Yoshiyuki Sowa, Atsushi Ikeda, Daisuke Mizuno. 2024-01-28. Non-Equilibrium Fluidization of Dense Active Suspension. https://arxiv.org/abs/2401.15658

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