The model of a one-dimensional chain of harmonically coupled particles in local double-well potentials is investigated analytically in the displacive regime. A perturbation treatment of the interaction of a kink (wall separating ordered clusters) with extended states (optical phonons modified by...

In this paper, we develop a relativistic Green matrix method in the Dirac formalism, which can be considered as ageneralization of the non relativistic Green function method of Scherer and Phariseau to calculate the surface states in a semi-infinite three-dimensional crystal. For simplicity,...

In adiabatic cooling experiments of Cu(NO3)22.5H2O an anomaly has been observed, which was explained by the onset of spin-ordering in the spin-pair system. Tachiki et al. proposed a spin-1/2 model to investigate this ordering. Ignoring a coupling between z-components of the spin, this model...

The motion of a quantum oscillator interacting with a quantized radiation field is studied. The exact solution shows that the motion of the oscillator is described by a Langevin-type equation in which the friction and the effective frequency depend on time. The physical conditions under which...

We investigate cooperative effects in energy relaxation and energy transfer for N atoms in a thermal radiation field with superradiance master equations as well as a closed set of coupled moment equations. Both spatially large and spatially small systems are considered. For small systems...

For systems which lack inversion symmetry the existence of transverse, odd-in-the-electric-field effects on transport properties cannot be excluded by spatial symmetry arguments alone. If, in addition, time reversal (Onsager) relations are invoked, transverse effects vanish in heat conduction...

A general theory is presented to calculate the wave vector and frequency dependent effective viscosity of a suspension of spheres. The resulting formal expression for the effective viscosity is then used to evaluate the coefficients of the linear and the quadratic terms in an expansion in the...

Experiments have been performed on the viscosity change of para and normal H2, and ortho and normal D2, under the influence of a magnetic field. This viscomagnetic effect is investigated as a function of the temperature between 140 K and room temperature. The data of this work are expressed in...

In this paper, we present an estimate of the coefficient of the first logarithmic term in the density expansions of transport coefficients of moderately dense gases. We formulate the theory for a gas of hard sphere molecules. Then the essential approximation made in this work is to replace the...

On the basis of the quantum-mechanical equations of motion and the statistical assumption that dynamical correlations present in the initial state may be ignored, a kinetic equation for a dilute neutrino system is derived. If the system is sufficiently uniform in space this equation reduces to...