https://doi.org/10.1051/epjconf/201610802044
Statistical Properties of Thermal Noise Driving the Brownian Particles in Fluids
1 Department of Physics, Faculty of Electrical Engineering and Informatics, Technical University of Košice, Park Komenského 2, 042 00, Košice, Slovakia
2 Laboratory of Radiation Biology, Joint Institute for Nuclear Research, 141980, Dubna, Moscow Region, Russia
a e-mail: jana.tothova@tuke.sk
b e-mail: vladimir.lisy@tuke.sk
Published online: 9 February 2016
In several recent works high-resolution interferometric detection allowed to study the Brownian motion of optically trapped microparticles in air and fluids. The observed positional fluctuations of the particles are well described by the generalized Langevin equation with the Boussinesq-Basset “history force” instead of the Stokes friction, which is valid only for the steady motion. Recently, also the time correlation function of the thermal random force Fth driving the Brownian particles through collisions with the surrounding molecules has been measured. In the present contribution we propose a method to describe the statistical properties of Fth in incompressible fluids. Our calculations show that the time decay of the correlator 〈Fth(t)Fth(0)〉 is significantly slower than that found in the literature. It is also shown how the “color” of the thermal noise can be determined from the measured positions of the Brownian particles.
© Owned by the authors, published by EDP Sciences, 2016
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
