Abstract:
On the basis of N. N. Bogoliubov's idea about the reduced description of dynamical
systems, the brownian motion in the equilibriun medium on the kinetic and hydrodynamic
stages of the evolution is considered. Integral equations are derived which make
it possible to evaluate the nonequilibrium distribution function in the perturbation theory
with respect to the small ratio $\mu$ of masses of particles of the medium and brownian
particles or to the interaction between these particles. Corresponding kinetic equations
are constructed, up to the terms of the order $\mu^3$, in the case $\mu\ll 1$. This makes it possible
determine the correction to the Einstein expression for the diffusion coefficient,
in the investigation of the process of diffusion of the brownian particle.