Nonequilibrium Probability Currents in Optically-Driven Colloidal Suspensions
Abstract
In the absence of directional motion it is often hard to recognize athermal fluctuations. Probability currents provide such a measure in terms of the rate at which they enclose area in the reduced phase space. We measure this area enclosing rate for trapped colloidal particles, where only one particle is driven. By combining experiment, theory, and simulation, we single out the effect of the different time scales in the system on the measured probability currents. In this controlled experimental setup, particles interact hydrodynamically. These interactions lead to a strong spatial dependence of the probability currents and to a local influence of athermal agitation. In a multiple-particle system, we show that even when the driving acts only on one particle, probability currents occur between other, non-driven particles. This may have significant implications for the interpretation of fluctuations in biological systems containing elastic networks in addition to a suspending fluid.
Cite
@article{arxiv.2310.12718,
title = {Nonequilibrium Probability Currents in Optically-Driven Colloidal Suspensions},
author = {Samudrajit Thapa and Daniel Zaretzky and Ron Vatash and Grzegorz Gradziuk and Chase Broedersz and Yair Shokef and Yael Roichman},
journal= {arXiv preprint arXiv:2310.12718},
year = {2024}
}
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