Mouvement Brownien dans une assemblee de batonnets minces dans la phase nematique

Using the kinetic methods of the Brussels school, we establish the equation (to the second order in the perturbation) for the return to equilibrium of the one-particle energy distribution function in the nematic phase of a fluid made of thin slabs interacting through a P2-type potential. On the basis of the mean field equilibrium theory developed by Maier and Saupe for such a fluid, we show that for a very heavy brownian particle, this equation reduces to a Fokker-Planck type equation; the friction coefficient thus obtained is compared with the friction coefficient obtained for the isotropic phase and we show that they are equal for the transition temperature.