A series of effects arising in a solid as a result of the nonlinear decay of a pumping wave is considered. The growth rate of the phonon subsystem instability caused by the decay process as photon → photon + phonon and the threshold value of the power flow of the pumping at which the...

The structure factor is calculated for a Bose fluid using an expression for S(k), which is approximately valid for all values of k. Marked fluctuations appear for k = 2.15 Å-1, near the roton dip in Ek, and at k = 3.65 Å-1 near the dip in the second branch of Ek. Our calculations are...

The extension of a previous general formulation of structural correlations in liquids enables us to derive accurate expressions for g(r) and S(k). Their asymptotic forms for large and small r and for large k values are compared with corresponding forms constructed by Verlet from his computer...

The one-electron momentum distribution function 〈akσ†akσ〉 for an electron gas is investigated by a diagrammatic analysis of perturbation theory. It is shown that 〈akσ†akσ〉 has the following exact asymptotic form for large k (k ⪢ pF; pF, the Fermi momentum): 〈akσ†akσ〉 =...

Within the framework of general statistical mechanics of irreversible processes the electrical resistivity of an open electron-phonon system is calculated. By means of the projection operator technique an evolution equation for coupled subsystems in a heat bath is derived and specialized for...

The study of generalized transport coefficients in two dimensions is continued. In this article, the thermal conductivity coefficient is examined. The Mori formalism is used and the set of variables consists of all finite multilinear products of two collective conserved variables, the energy...

The theory of the ground state of the two-dimensional non-ideal Bose gas is presented. The conditions for the validity of the ladder and the Bogolubov approximations are derived. These conditions ensure the existence of a Bose condensate in the ground state of two-dimensional systems. These...

The dynamic properties of a stochastic n-vector model are investigated for T Tc in d=4−ϵ dimensions. Besides the non-conserved order parameter the model involves also the conserved densities of generators of the symmetry group O(n). We calculate the excitation spectra of those conserved...

The correlation function of temperature fluctuations around homogeneous stationary states of the ballast resistor is evaluated by extending the theory of thermal fluctuations around equilibrium states to non-equilibrium situations. It is found that equal-time temperature fluctuations become...

In this paper we investigate the relation (dynamical equation of state) among the (mechanical hydrostatic) pressure P, the volume ν and the temperature T of an isotropic medium with an arbitrary number, say n, of scalar internal degrees of freedom. It is assumed that the irreversible processes...