Affiliation - University of Wisconsin-Madison
Title of Talk - Shake your hips: an active particle with a fluctuating propulsion force
Event Link - https://upenn.zoom.us/j/99792332298?pwd=R1JXYmh2aGI1OUhuUzg5VFhuU0M0Zz09
The active Brownian particle (ABP) model describes a microswimmer, synthetic or living, whose direction of swimming is a Brownian motion. The swimming is due to a propulsion force, and the fluctuations are often assumed thermal in origin. We present a model where the fluctuations arise from nonthermal noise in a propelling force acting at a single point, such as that due to a flagellum. We carefully take the overdamped limit and find several modifications to the traditional ABP model. Since the fluctuating force causes a fluctuating torque, the diffusion tensor describing the process has a coupling between translational and rotational degrees of freedom. An anisotropic particle also exhibits a noise-induced drift. We show that these effects have measurable consequences for the long-time diffusivity of active particles, in particular adding a contribution that is independent of where the force acts. This is joint work with Jiajia Guo.