"Phases of active matter composed of multicellular magnetotactic bacter" by Alexander Petroff, Alejandra Rosselli-Calderon et al.
 

Physics

Phases of active matter composed of multicellular magnetotactic bacteria near a hard surface

Document Type

Article

Abstract

We investigate the motion of multicellular magnetotactic bacteria (MMB) near a hard surface. Directing MMB towards a flat surface causes them to accumulate about the wall as an active gas. MMB are exponentially distributed about the surface with a penetration depth determined by the typical distance an MMB swims before it aligns with the ambient field. Increasing the magnetic field past a critical value, at which the penetration depth is of order the size of an MMB, causes the active gas to condense into a two-dimensional active fluid. Measurements of MMB motion in this phase reveal that contact with the surface enhances rotational diffusion by a factor of 8 and that velocity fluctuations are Laplace distributed. The fluid undergoes a percolation transition at a critical magnetic field. Supercritical active fluids exhibit dynamic voids, which limit the relaxation of density fluctuations. We describe the possible ecological significance of these results.

Publication Title

Physical Review Fluids

Publication Date

5-2022

Volume

7

Issue

5

ISSN

2469-990X

DOI

10.1103/PhysRevFluids.7.053102

Keywords

bacteria, diffusion in liquids, magnetic fields

Cross Post Location

Student Publications

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