Join the Department of Mathematics, Applied Mathematics, and Statistics (MAMS) on **October 31, 2018** for an Applied Mathematics Seminar given by **Gill Ariel, Associate Professor, Bar-llan University Department of Mathematics**. Dr. Ariel will speak on **“Chaos and Levy Walks in Swarming Bacteria.”** The seminar will be held in **Yost 306, from 3:15 – 4:15 PM**.

**Abstract:** Bacterial swarming is a collective mode of motion in which cells migrate rapidly over surfaces. Swarming is typically characterized by densely packed groups moving in coherent patterns of whirls and flows. Recent experiments showed that within such dense swarms, bacteria are performing super-diffusion that is consistent with Levy walks – random processes in which the Gaussian central limit theorem fails. We present a simple model of a spheroidal, self-propelled particle, moving in the effective, vortex-like flow generated by all other bacteria. Mathematically, the model presents a new mechanism for Levy walks in chaotic maps that are reversible but not volume preserving. Levy walking emerges from sticking close to regular, fractal-like areas with multiscale periodicities. A bifurcation separates a chaotic, super-diffusive regime and a regular, ballistic one. Biologically, it explains how cells can fine-tune the geometric properties of their trajectories.

Joint work with Avraham Be’er (BGU) and Andy Reynolds (Rothamsted Research, UK).