Curvature Induced Activation of a Passive Tracer in an Active Bath

TL;DR

This study uses simulations to show that even slight curvature in a passive tracer can induce directed motion in an active nanoparticle bath, offering new ways to control transport properties through geometry.

Contribution

It demonstrates how tracer curvature influences activation in active baths and introduces scaling arguments to quantify this effect.

Findings

Small curvature induces directed motion in passive tracers.

Tracer geometry can be tailored to control transport in active media.

Active bath imparts effective activation even with minimal curvature.

Abstract

We use numerical simulations to study the motion of a large asymmetric tracer immersed in a low density suspension of self-propelled nanoparticles in two dimensions. Specifically, we analyze how the curvature of the tracer affects its translational and rotational motion in an active environment. We find that even very small amounts of curvature are sufficient for the active bath to impart directed motion to the tracer which results in its effective activation. We propose simple scaling arguments to characterize this induced activity in terms of the curvature of the tracer and the strength of the self-propelling force. Our results suggest new ways of controlling the transport properties of passive tracers in an active medium by carefully tailoring their geometry.