Multimode contributions to the anomalous shear viscosity

Abstract

The results of a mode–mode coupling calculation of the anomalous shear viscosity are presented. By explicitly including trilinear variables in the generalized Langevin equation expressions for the anomalous wave vector and frequency dependent shear viscosity are obtained which incorporate both vertex and frequency corrections. Explicit calculations of the anomalous viscosity of xenon have been carried out. The vertex corrections are found to be important and give rise to an additional anomalous contribution which, close to the critical point, is about 20% of the contribution considered in previous calculations. The inclusion of this effect leads to a much closer agreement with the experimental results. In addition, results are presented for the wave vector and frequency dependence of the shear viscosity which are relevant for Rayleigh linewidth calculations.