We compute exactly the local magnetization <σxj> for the semi-infinite XY-chain at zero temperature as a function of the distance from the boundary j and the anisotropy parameter γ. It is shown that in the limit j → ∞, γ → 0 the local magnetization has the scaling form <σxj> = γ14f(2γj). We...</σxj></σxj>

A systematic development for a Multivariate Master Equation (MME), describing reaction diffusion systems, is presented along the same lines as the Chapman-Enskog development of kinetic gas theory. Diffusion, which occurs at a very fast rate, brings the system near a state of diffusional...

The critical temperature for a quenched Ising model on the square lattice, with vertical random interactions is found exactly. For the usual mixed ferro- and antiferromagnetic δ-distribution of the bonds, the calculated phase transition temperature versus the concentration of antiferromagnetic...

An exact steady-state density operator is obtained for a model describing the collective behaviour of a system of N two-level atoms. The model yields a Fokker-Planck equation which does not satisfy detailed balance. The density operator is further employed to obtain exact analytical expressions...

Using Bourret's approximation the effect of a finite correlation time τc of the velocity on the averaged displacement of a Brownian moving particle is investigated. It turns out that in a rather general special case the usual parabolic diffusion equation is replaced by a hyperbolic one. Both,...

A statistical theory of nonlinear dispersive waves is developed on the basis of the Korteweg-de Vries (KdV) equation. The asymptotic expressions of the n(≧3)-point velocity correlation-functions are derived analytically from the given initial velocity distribution. The dependence of various...

Explicit expressions are derived for the time correlations between x- and y-components of spin and their frequency-Fourier transforms in the one-dimensional XY-model in the high-temperature limit (β = 0). The results can be expressed as a linear combination of at most three Gaussians multiplied...

We study the density of states of a one-dimensional tightbinding electron model with random hopping elements. The Hamiltonian is H = -∑iJi+12(a+iai+1+a+i+1ai), where the Ji+12's are independent identically distributed random variables. It is proved that the single particle density of states...

Experimental results on the influence of a magnetic field on linear, spherical top and symmetric top molecules have been analyzed in terms of the kinetic theory based on the Waldmann-Snider equation. The traditional analysis on the basis of the two angular momentum polarizations W· and W ∧ J...

Referring to the results of a previous paper dealing with the pair distributions in a fully ionized dilute hydrogen plasma it is concluded that the pair distributions in binary electrolytes up to concentrations c ≅ 1 mo1/1 take the form n(r) = exp[-β(Ṽ(r) + V(hs)(r))]. Here Ṽ(r)...