For an eēvev̄e-mixture, in which the particles interact on the basis of the Weinberg-Salam model, the influence of the reactive eē[harr ]vev̄e collisions on the bulk viscosity is investigated. It is found that the bulk viscosity decreases owing to the occurrence of these reactive collisions....

MacDonald's theorem, which expresses the spectral density of a randomly fluctuating variable α(t) in terms of the finite time average of that variable, αθ(t), is generalized for multivariate processes. For purely random processes, having a white spectrum, this also yields the corresponding...

In this paper a generalization of the traditional non-relativistic Schrödinger equation is considered. It is a wave equation of second order in time and fourth order in the space coordinates for scalar fields. The equation has certain features, which make it a closer analogue of the...

The density dependence of the proton magnetic shielding constants in liquid methanol and ethanol has been accurately measured at a temperature of 29.2°C and at external pressures between 1 and 2500 bar. For comparison, a measurement in the vapor coexisting with the liquid at 29.2°C has also...

We show that the long time behaviour of the velocity correlation function in a two-dimensional classical system with pairwise repulsive potentials can be represented by a series expansion of the form 〈υ1xυ1x(t)〉 = d0t−1 + d1t−1log t/t0 + d2t−1(log t/t0)2 + …, where t0 is mean free...

New tools for the solution of stochastic differential equations are presented. It is shown that there exist simple formulae for splitting correlations, which arise when dealing with widely used models of random processes such as Poisson, gaussian and Markov jump processes with an exponential...

The fourth order terms in Bose-operators of the spin deviations at low temperatures are taken into account in order to evaluate the corrective contribution to the spin-wave dispersion law and the corresponding differential cross section of the magnetic neutron scattering in ferromagnets with S =...

Our new theory of fluctuation was applied to the undamped spiking in lasers with single mode saturable absorption. At the marginal points, which lead to limit cycles, it was found that the irreversible circulation α and the residual circulation α′ diverge together with the variance σ. The...

The dynamics of the Dicke-maser model is considered when the phase transition to a spontaneous coherent state takes place. In the molecular field approximation an expression for the atomic correlation function is found which shows dynamic peculiarities of the spontaneous coherent state (SCS) in...

The variational principle is presented for a continuous renormalization transformation. It is shown that a strict application of the variational method leads to a singularity in the variational parameter which is related to that in the free energy. The equations governing the behaviour of the...