For an electron-phonon system with several equivalent bands a generalized transport and response theory is derived which serves as microscopic justification of a model for the structural phase transition in A15-compounds. By means of a generating functional approach a self-consistent formulation...

Experimental results are reported for the magnetic field influence on the thermal conductivity of CH3CN-Ar gas mixtures at various compositions for T = 300 K. The observed field dependence is analyzed in terms of the contributions from the W[J](2) and WJ polarizations.

A model for the dynamics of the coupling between the orientations of the ordered CH4 molecules in phase II of solid methane at low temperatures is proposed. The model is equivalent to the dynamics of disordered solid hydrogen. The effective interaction strength is determined by the overlap of...

The damping theory is correctly applied to the coupled systems in contact with respective reservoirs. Differences between the present rigorous treatment of the damping theory and the conventional one are explicitly shown for an exactly solvable model of the parametric amplifier. The deviation...

A perturbation series is obtained which expresses the pressure, Ursell functions and distribution functions of a quantum fluid in terms of those of the unperturbed fluid having the same temperature and fugacity. The pair interaction potential of the unperturbed fluid is a non-analytic function...

The master equation for a general Markov process that shows a transition from monostable to bistable behaviour will be evaluated systematically in terms of a small parameter, namely the reciprocal size of the system. The expansion is uniformly valid also at the critical point. The fundamental...

Van der Waals' assumption that the parameter a in his model is independent of density and temperature is reexamined for Lennard-Jones particles, using two different types of soft repulsive core potentials: the positive portion of the Lennard-Jones potential and the portion of the Lennard-Jones...

By means of the method of computer simulation, the coefficient of viscosity for a system consisting of square-well molecules has been determined at densities up to the critical one. It has been found that the superposition of an attractive well on the hard sphere has a marked influence on the...

The normal mode analysis of systems of linear macroscopic equations in irreversible thermodynamics is extended in several ways. When the characteristics equation has multiple roots, there may appear normal solutions that do not decay purely exponentially, but a closed form for the Green function...

A two-sublattice spin model is proposed with special four-spin interactions besides the usual exchange terms. The four-spin interaction terms are assumed not to be the even functions of the spin sublattice operators. Thermodynamical properties of this model are investigated in the molecular...