We consider a system consisting of two immiscible fluids and their interface. The equilibrium interface is assumed to be planar. The velocity fields in the fluids are described by the linearized Navier-Stokes equations with appropriate boundary conditions at the interface. Explicit expressions...

The motion of a Brownian particle in an external field can be described on two levels: by a Fokker-Planck equation for the joint probability distribution of position and velocity, and by a Smoluchowski equation for the distribution in position space only. We derive the second description, with...

The correct results for the transport coefficients of a relativistic gas of hard spheres are presented.

The decay of an ensemble of two-level molecules is described by a quantum-mechanical formalism involving single molecule operators. Equations of motion are obtained for the operators by means of a pertubative analysis, containing spontaneous decay terms and those that connect different...

The general scaling theory of transient phenomena near the instability point, which has been proposed by the author, is applied to investigate the fluctuation and relaxation of superradiance from the complete inversion. This study gives a foundation or justification of the treatment of Glauber...

The pressure, energy and self-diffusion coefficient have been calculated for an 11-6-8 fluid using the method of molecular dynamics. A comparison with data for argon, krypton and xenon is presented. It is shown that agreement between theory and experiment for the thermodynamic properties is...

Three simple stochastic models for orientational correlation functions are discussed: The J-diffusion model, the cumulant expansion and the stochastic Liouville equation are compared with the computer experiments for partially rough hard spheres. Although no model gives an accurate description...

To describe dynamical properties of a system of interacting Brownian particles stochastic transport equations are derived for the positions of the particles and their concentration fluctuations. This is achieved by an expansion of the Langevin equation for the momenta in terms of the reciprocal...

In this paper a general expression is given for the wave vector- and frequency-dependent dielectric susceptibility tensor of a composite perfect lattice with an arbitrary number of fixed nonpolar molecules with given polarizability tensor in a unit cell. The general expression is applied to a...

The one dimensional quantum mechanical XY model is studied by the renormalization group method. To second order in the cumulant expansion, no non-trivial fixed points are found. The calculated free energy is in excellent agreement with that of the exact solution.