In this paper a simple variational method is proposed for the solution of the integral equations for hard-core fluids. The variational method is applied to the equations of the mean-spherical approximation for systems consisting of square-well particles at very high densities. Using the static...

A momentum space renormalization is presented for the sine-Gordon model with an arbitrary cut-off function. In contrast to previous work the present method reproduces the slope of the critical line as found from the Kosterlitz renormalization of the equivalent Coulomb gas and is also applicable...

The Brownian motion of the Duffing oscillator is analyzed in the case when the oscillator damping is small compared with its frequency, whereas the nonlinearity may be arbitrary. The expressions for the time-correlation functions of coordinates are obtained in an explicit form. If the...

Experimental results are presented for the influence of a magnetic field on the viscosity of NH3-He and NH3-Ar and on the thermal conductivity of NH3-Ar gas mixtures. Data are reported for various mixture compositions at room temperature. The data are analyzed in detail in an attempt to clarify...

We consider a class of scalar nonlinear Boltzmann equations describing the evolution of a microcanonical ensemble in which sub-systems exchange internal energy ‘randomly’ in binary interactions.

We derive equations of motion for a point particle with spin in an external electromagnetic and in an external scalar field. The derivation is based on the ten conservation laws of linear and angular momentum and on a general expression for the current by which the particle interacts with the...

A homogeneous shear nonequilibrium molecular dynamics algorithm has been applied to a system of 108 particles interacting with an m-6-8 potential. The viscosity was calculated at three densities corresponding approximately to the triple point, two-thirds melting and critical density. Comparing...

The master equation for a diffusion process that takes place in an external potential will be evaluated systematically in terms of a small parameter, namely the diffusion coefficient. Contrary to the known expansion the present solution is not only uniformly valid in the normal monostable and...

The equilibrium statistical mechanics of a nearly classical one-component plasma, submitted to a strong magnetic field, is studied, in three or two dimensions, by a suitable expansion of the Wigner distribution function. A strong magnetic field quenches the quantum fluctuations transverse to the...

Approximate values for the ground-state energy of one- and two-dimensional antiferromagnetic systems are determined with cells of an even number of spins. The interaction between the cells is treated as a perturbation.