The effective Hamiltonian approximation is used to calculate the critical temperature of a new class of magnetic systems, in which exchange integrals can be either of Ising or Heisenberg type. The values of the exchange integrals are supposed to be given according to different gaussian...

The hopping rate equation for charged particles with self-consistent Coulomb interaction on an arbitrary periodic lattice can be solved exactly. It is shown that if one scales the time t and the distances x (including the characteristic length l = [(e2/ϵ0)∂n0/∂μ]−12)as t → λ2t, x →...

Given the C∗-algebra A of observables, the KMS condition is formulated in terms of the time evolution α∗t of a set S0 ⊂ S(A) of “physical” states subject to certain natural conditions. α∗t need not be defined by an automorphism group of A. It is shown that, for a KMS state ω,...

A new development of the kinetic many-body treatment of the short-lived large energy fluctuation (SLEF) of N0 ≥ 1 heavy particles of classical solids up to ϵ0 ⪢ ϵ0 = 3N0kT and of SLEF-induced rate processes is presented. The finiteness of the SLEF lifetime Δτ ≈ 10−13−10−12 s and...

The Onsager-Machlup Lagrangian for diffusion processes in curved spaces is determined by evaluating the covariant path integral by means of a spectral analysis of smooth trajectories in Riemannian normal coordinates. The Lagrangian involves a novel curvature scalar potential term v=−(18)R. The...

Using the formalism of force-force correlation functions developed recently, the Spitzer formula for the conductance is generalized by taking into account the following effects: (1) dynamical screening; (2) ion-ion correlations by the ion structure factor; (3) deviations from Coulomb's...

The first part of this paper is an attempt to formulate and motivate additional work on the important problem of obtaining global bounds applicable to the controlled truncation of the paper relates specifically to the linear birth, quadratic death model. Asymptotic results are given for the...

With the use of an appropriately generalized Waldmann-Snider collision (super-) operator, a unified kinetic theory treatment of depolarized light scattering (both depolarized Rayleigh and rotational Raman) and their related linewidths is presented for gases of rigid rotor molecules. Explicit...

A class of initial value problems is considered where a specified particle has a given distribution ƒ(1)(z1;0) and the rest are in equilibrium at t=0. A formally exact expansion is obtained for a certain n-particle reduced distribution-function ƒ(1)(z1, z2, …, zn;t) in terms of the...

The distorted wave Born approximation is used as a basis for understanding the cross sections which govern the production and relaxation of internal state polarizations, in gaseous ammonia, in the presence of shear flow or thermal gradients. For viscous flow, it is shown that the dominant...