Transport and Diffusion Enhancement in Experimentally Realized Non-Gaussian Correlated Ratchets

TL;DR

This study investigates how non-Gaussian active fluctuations, similar to cellular processes, can enhance transport and diffusion in a colloidal particle system driven by asymmetric potentials, revealing optimal conditions for maximum particle velocity.

Contribution

It experimentally and numerically demonstrates that non-Gaussian active bursts can significantly improve transport efficiency compared to Gaussian noise in a ratchet system.

Findings

Maximum particle velocity occurs at sparse, finite-correlation bursts.

Non-Gaussian bursts outperform Gaussian noise in transport enhancement.

Optimal noise conditions depend on burst frequency and distribution.

Abstract

Living cells are known to generate non-Gaussian active fluctuations significantly larger than thermal fluctuations owing to various active processes. Understanding the effect of these active fluctuations on various physicochemical processes, such as the transport of molecular motors, is a fundamental problem in nonequilibrium physics. Therefore, we experimentally and numerically study an active Brownian ratchet comprising a colloidal particle in an optically generated asymmetric periodic potential driven by non-Gaussian noise having finite-amplitude active bursts, each arriving at random and decaying exponentially. We find that the particle velocity is maximum for relatively sparse bursts with finite correlation time and non-Gaussian distribution. These occasional kicks, which produce Brownian yet non-Gaussian diffusion, are more efficient for transport and diffusion enhancement of the particle than the incessant kicks of active Ornstein-Uhlenbeck noise.