Intermittent transport phenomena in active matter systems

Active matter systems, ranging from swimming microorganisms to catalytic colloids, are characterized by transforming energy into directed motion, driving them far from equilibrium and generating a range of unusual physical phenomena. Their dynamics are subject to strong stochastic fluctuations and tumbling mechanisms that compete with their directed swimming motion, leading to large-scale diffusive spreading. In addition, external stimuli, complex fluid properties, and geometric confinement, omnipresent in their natural environments, can strongly modify this picture and lead to intricate intermittent dynamics. In this talk, I will discuss a theoretical framework, based on renewal equations, to analytically describe these transport processes and quantitatively characterize the dynamics of run-and-tumble E. coli bacteria [1] and sperm cells under various environmental conditions.

[1] C Kurzthaler, Y Zhao et al. Phys. Rev. Lett. 132 (2024)