�Diffusion and clustering of passive particles in a bath of micro-algae��Dr. Julien Bouvard�

1

Reference: Bouvard J, Moisy F, Auradou H. Ostwald-like ripening in the two-dimensional clustering of passive particles induced by swimming bacteria[J]. Physical Review E, 2023, 107(4): 044607.�

1. Introduction

2

Active particle is any entity that is internally driven (with continuous supply of energy). lt generates some motion by dissipating that energy. Continuous injection of energy drive them out of equilibrium.

Ramamonjy et al. PRL 2022

Li J et al. Science Robotics 2017

Guasto J S et al. PoF 2011

Drescher K et al. PRL 2010

Chlamydomonas reinhardtii

Escherichia coli

Wu X L et al. PRL 2000

Dolai P et al. Soft Matter 2018

Ostwald-like ripening in the two-dimensional clustering of passive particles induced by swimming bacteria

Burkholderia contaminans

Reference: Bouvard J, Moisy F, Auradou H. Ostwald-like ripening in the two-dimensional clustering of passive particles induced by swimming bacteria[J]. Physical Review E, 2023, 107(4): 044607.�

2. Experiments

6

Bouvard J et al. PRE 2023

Experimental Set-up

Trackmate in ImageJ

Phototaxis

Collision of beads

Results

Residual flow

Conclusion

Leptos K C. PRL 2009

Conclusion

=1x10^-3 μm²s^-1

Bead’s radius a= 1μm

Bead’s radius a= 25μm

3. Future work

11

1. Experiments will be performed under the same conditions using OD=5 and OD=20, trying to avoid light, residual flow and collision of beads.

​

• Attempt to simulate MSD of passive particles in a bacterial bath

Volpe G et al. AJP 2014

Thank you very much!

13