Bistability in orbital trajectories of a chiral self-propelled particle interacting with an external field

TL;DR

This study investigates how a chiral self-propelled particle with an eccentric sensor interacts with an external light field, revealing bistability and diverse orbital behaviors through experiments and modeling.

Contribution

It introduces a mathematical model linking sensor eccentricity and stochastic effects to orbital bistability in self-propelled particles.

Findings

Experimental observation of orbital trajectories with two radial preferences.

Identification of sensor eccentricity and noise as causes of bistability.

Demonstration of trapped and diffusive behaviors depending on parameters.

Abstract

In this work, the dynamics of a self-propelled stochastic particle under the influence of an axisymmetric light field was experimentally studied. The particle under consideration has the main characteristic of carrying a light sensor in an eccentric location. For the chosen experimental conditions, the emerging trajectories were orbital, and, more interestingly, they presented two preferential radial distances. A mathematical model incorporating the key experimental components was introduced. By means of numerical simulations and theoretical analysis, it was found that, in addition to the orbiting behavior, the sensor location could produce trapped or diffusive behaviors. Furthermore, the study revealed that stochastic perturbation and the eccentric location of the sensor are responsible for inducing bistability in the orbital trajectories, in agreement with the experimental observations.