Rapid-prototyping a Brownian particle in an active bath. Issue 35 (22nd July 2020)

• Record Type: Journal Article
• Authors: Park, Jin Tae; Paneru, Govind; Kwon, Chulan; Granick, Steve; Pak, Hyuk Kyu
• Is Part Of: Soft matter. Volume 16:Issue 35(2020)
• Page Start: 8122
• Page End: 8127
• Publication Date: 2020-07-22
• Subjects: Soft condensed matter -- Periodicals; 530.413
• DOI: 10.1039/d0sm00828a
• Languages: English
• ISSNs: 1744-683X

Abstract

Abstract : We study the diffusion of a Brownian particle in presence of programmed active forces. The model's generic simplicity allows us to quantify the observed enhanced Gaussian or non-Gaussian diffusion in an active bath. Abstract : Particles kicked by external forces to produce mobility distinct from thermal diffusion are an iconic feature of the active matter problem. Here, we map this onto a minimal model for experiment and theory covering the wide time and length scales of usual active matter systems. A particle diffusing in a harmonic potential generated by an optical trap is kicked by programmed forces with time correlation at random intervals following the Poisson process. The model's generic simplicity allows us to find conditions for which displacements are Gaussian (or not), how diffusion is perturbed (or not) by kicks, and quantifying heat dissipation to maintain the non-equilibrium steady state in an active bath. The model reproduces experimental results of tracer mobility in an active bath of swimming algal cells. It can be used as a stochastic dynamic simulator for Brownian objects in various active baths without mechanistic understanding, owing to the generic framework of the protocol.