Coupling between the angular momentum J and the nuclear spins of a molecule modifies those contributions to the transport properties of a molecular gas which arise from the macroscopic orientational polarization. This (low pressure) effect is studied in detailfor molecular HD at low temperature...

Two coupled, inhomogeneous relaxation equations for the friction pressure tensor and the alignment tensor are derived within the framework of irreversible thermodynamics. These equations are solved for a specific geometry, viz. flow between flat plates, and for a velocity gradient of the form...

The diagrammatic technique for the standard basis operators and the expansion in powers of 1/z (where z is the number of spins interacting with any given spin) are used to calculate the energies of magnons (in the ferromagnetic and quadrupolar phases) and quadrons (in the ferromagnetic phase)...

The fixed point structure resulting from the approximate renormalization group equations obtained by shifting bonds on the square Ising lattice is considered as a function of a free parameter h appearing in the definition of these equations. Next to the fixed point S considered by Kadanoff which...

The transport equation for a neutrino system derived previously is extended to include binary collisions involving electrons, positrons and antineutrinos. The transition amplitudes for these collision processes are specified in terms of an effective Hamiltonian density following from the...

The magnetic susceptibility, electrical conductivity, and specific heat of the Holstein-Fröhlich modified Hubbard model are obtained with the restriction that the chemical potential μ be identically equal to one-half the intra-atomic electronic Coulomb repulsion U. Contributions to the...

We analyse the end-to-end distribution function of a polymer chain with a pair-wise interaction between its repeat units in a continuous space. By means of a cluster expansion we classify its contributions according to the number and arrangement of the contacts between the repeat units. We then...

The one-dimensional anisotropic XY model with alternating nearest-neighbour interactions and magnetic moments is investigated. The singularities of the susceptibility χzz in the ground state are studied in detail. In the general anisotropic case χzz can exhibit two logarithmic singularities at...

A system of exact algebraic relations is derived for the spin correlation functions on any so-called “boundary set” of an Ising model on an arbitrary planar graph. One way of expressing these relations is to say that every higher-order correlation function is equal to a Pfaffian of the pair...