ON THE POSSIBILITY OF THE EXISTENCE OF THE SPATIALLY PERIODICAL BOSE CONDENSATE

The possibility of constructing the theory relating to a spatially periodical Bose condensate in the model of a weakly nonideal Bose gas is studied. Equations for determining a spatially periodical order parameter at the temperature T = 0 are formulated and their one-periodical solutions are obtained based on the isolated Bose condensate method. Here it is possible to neglect the contribution of quasiparticles to the thermodynamics of a boson system. The problems of thermodynamic stability of the spatially periodical Bose condensate are presented in short.У роботi вивчено можливiсть побудови теoрiї просторово-перiодичного бозе-конденсату в моделi слабконеiдеального бозе-газу. На основi методу видiленого бозе-конденсату сформульовано рiвняння для визначення просторово-перiодичного параметра порядку при температурi T = 0 , коли можна знехтувати внеском квазiчастинок до термодинамiки системи бозонiв, та знайдено їх одноперiодичнi розв’язки. Коротко викладено питання термодинамiчної стiйкостi просторово-перiодичного бозе-конденсату

On the possibility of the existence of the spatially periodical Bose condensate

The possibility of constructing the theory relating to a spatially periodical Bose condensate in the model of a weakly nonideal Bose gas is studied. Equations for determining a spatially periodical order parameter at the temperature T = 0 are formulated and their one-periodical solutions are obtained based on the isolated Bose condensate method. Here it is possible to neglect the contribution of quasiparticles to the thermodynamics of a boson system. The problems of thermodynamic stability of the spatially periodical Bose condensate are presented in short.У роботi вивчено можливiсть побудови теoрiї просторово-перiодичного бозе-конденсату в моделi слабконеiдеального бозе-газу. На основi методу видiленого бозе-конденсату сформульовано рiвняння для визначення просторово-перiодичного параметра порядку при температурi T = 0 , коли можна знехтувати внеском квазiчастинок до термодинамiки системи бозонiв, та знайдено їх одноперiодичнi розв’язки. Коротко викладено питання термодинамiчної стiйкостi просторово-перiодичного бозе-конденсату

The kinetic theory of the cosmological models

Theory of Friedman cosmological models is developed. It is based on a common and consistent solution of the kinetic equation for the galaxies distribution function in the approximation of a self-consistent gravitational field and the Einstein equations. Kinetic approach to the relic radiation theory is also under consideration

Superfluidity of a condensate with np pairing correlations in asymmetric nuclear matter

Influence of asymmetry on superfluidity of nuclear matter with triplet-singlet pairing of nucleons (in spin and isospin spaces) is considered within the framework of a Fermi-liquid theory. Solutions of self-consistent equations for the energy gap at T=0 are obtained. It is shown, that if the chemical potentials of protons and neutrons are determined in the zero gap width approximation, then the energy gap for some values of density and asymmetry parameter of nuclear matter demonstrates double-valued behavior. However, with account for the feedback of pairing correlations through the normal distribution functions of nucleons two-valued behavior of the energy gap turns into universal one-valued behavior. At T=0 the energy gap has a discontinuities as a function of density in a narrow layer model. These discontinuities depend on the asymmetry parameter

Hydrodynamic theory of magnets with strong exchange interaction

A microscopic approach to the description of multisublattice magnets with strong exchange interaction is proposed. Low-frequency dynamics of such magnets is characterized by the appearance of an additional dynamical variable, i.e., the orthogonal matrix of rotation, which corresponds to the total breaking of spin invariance [broken SO(3) symmetry]. The structure of the source that breaks the symmetry of the equilibrium Gibbs distribution is established. The quasiaverage representation is generalized to weakly anisotropic, locally equilibrium states. The thermodynamics of such states is constructed. The method of reduced description is formulated and in its framework the hydrodynamic equations for the density of total spin and the matrix of rotation are obtained. The spectra of spin waves are found and the number of Goldstone and activation modes is determined. Two-sublattice ferrimagnet is considered as a special case of the magnet with broken SO(3) symmetry, which corresponds to the special dependence of thermodynamic functions from the matrix of rotation

Hamiltonian dynamics of the condensed media with spontaneously broken symmetry

Consiglio Nazionale delle Ricerche (CNR). Biblioteca Centrale / CNR - Consiglio Nazionale delle RichercheSIGLEITItal