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.
MathBio Seminar
Tuesday, March 14, 2023 - 4:00pm
Jean-Luc Thiffeault
University of Wisconsin Madison
Other Events on This Day
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Simplicial complexity and L^2 invariants
Rademacher Lectures
3:45pm
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Liouville conformal field theory and the quantum zipper
Probability and Combinatorics
3:30pm