Swimming Bacteria: Single swimmer and collective motion

Guangyin Jing, Professor in Soft Matter Physics Lab, Northwest University, Xi’an, China

Flagellated bacteria, refined through billions of years of evolution, have ingeniously overcome the fundamental constraints of locomotion at low Reynolds numbers, as imposed by the scallop theorem. This allows them to swim efficiently and navigate complex environments. In this talk, I will first discuss how individual bacteria respond to externalflows through orientation dynamics, focusing on two key navigation mechanisms: chirality-induced drift and nematic alignment. Extending from single swimmers to populations, I will then briefly present experimental investigations of collective bacterial motion and discuss how activity and environmental adaptation govern the emergence of collective patterns.