Longterm Influence of Inertia on the Diffusion of a Brownian Particle

Abstract

We demonstrate experimentally that a Brownian particle is subject to inertial effects at long time scales. By using a blinking optical tweezers, we extend the range of previous experiments by several orders of magnitude up to a few seconds. The measured mean square displacement of a freely diffusing Brownian particle in a liquid shows a deviation from the Einstein-Smoluchowsky theory that diverges with time. These results are consistent with a generalized theory that takes into account not only the particle inertia but also the inertia of the fluid surrounding the particle. This can lead to a bias in the estimation of the diffusion coefficient from finite-time measurements. We show that the decay of the relative error is polynomial and not exponential and, therefore, can have significant effects at time scales relevant for experiments.

5 pages, 4 figures

References in corpus (3)

• Work and heat probability distribution of an optically driven Brownian particle: Theory and experiments
• Anisotropic memory effects in confined colloidal diffusion
• Persistent correlation of constrained colloidal motion

Cited by in corpus (6)

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• Inertial delay of self-propelled particles
• A Step-by-step Guide to the Realisation of Advanced Optical Tweezers
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• Optical Tweezers: A Comprehensive Tutorial from Calibration to Applications