Showing papers in "Russian Physics Journal in 1986"

Canonical quantization of a special class of gauge theories

Abstract: The class of theories (special-class theories) to which the most popular physical field theories belong is described in a general form. Various ways of quantizing special-class theories are considered, and their equivalence is demonstrated. The explicit form of the generators of the gauge transformations are obtained, and the equivalence of the definition of physical functions in the Lagrangian and the Hamiltonian formalisms is demonstrated.

Spectroscopic parametrization of the method of PNDO

Abstract: Special spectroscopic parameterization of the semiempirical PNDO method for calculating the spectral characteristics of polyatomic heterocyclic molecules is proposed. The parameters are calibrated according to the experimental absorption spectra, photoelectronic spectra, and the dipole moments of benzene and its derivatives.

Orthogonal polynomials in the lie algebras

Abstract: We present a method of constructing orthogonal polynomials generated by pairs of Hermitian operators in representations of Lie algebras. All known classical polynomials of both discrete and continuous argument are generated naturally by the simplest Lie algebras.

Birefringence and the gyrotropy of the compounds II-IV-V2

Abstract: The crystals II-IV-V2 with the structure of chalcopyrite exhibit intense birefringence whose quantity according to the structural model is determined by the anisotropy of the local field and by the anisotropy of the polarizability of the II–V bond. Birefringence dispersion and its thermal and barometric coefficients are interpreted in the three-contribution model as boundary, E1 and E2-transitions and correspond to a compressed binary analog. The crystals II-IV-V2 possess gyrotropic properties that are manifested in elliptical birefringence and exhibit peculiarities in the optical spectra near the isotropic point. The dispersion of gyrotropy is determined by the presence of linear terms in the dispersion zone. The quantity of gyrotropy is related to the deformation of the tetrahedron II-V4. The anisotropy of the optical properties of the crystals II-IV-V2 can be used for devices in nonlinear optics for the parametric transformation of light.

Mechanism for induction of einstein gravitation

Abstract: A quantum theory of Weyl gravitation, conformally bound to material, is considered. Direct solution of the renormalization group equation is used to obtain the effective action to the accuracy of terms linear in curvature. It is shown that the theory admits a phase transition of the first sort, caused by curvature, as a result of which Einstein gravitation is induced.

Sound waves in a nonequilibrium molecular gas

Abstract: We consider relaxation processes of dynamics of a nonequilibrium vibrationally excited gas (Tv>T0). It is shown that the effective heat capacities can become negative in such a medium. This leads to anomalous effects during propagation of long-wave sound: there exist regions (in the parameter Tv/T0) of sharp enhancement and reduction of its speed, as well as regions where low-frequency sound can generally not propagate. Instability conditions are investigated for various temperature dependences of vibrational relaxation times. It is shown that in a certain region of Tv/T0 values one has amplification of sound waves, related to the formation of second viscosity in these media. In this case a change in the amount of medium nonequilibrium can vary the sound frequency corresponding to maximum amplification.

Calculation of the band structure of GaN and InN using the pseudopotential method

Abstract: The model pseudopotential method is used to calculate the band structure of the hexagonal semiconductors GaN and InN A comparison is carried out of the features of the reflection spectrum and the characteristic inelastic electron-scattering loss spectrum with the interband transitions at points and lines of high symmetry By using one and the same interpretation, satisfactory agreement is obtained with experiment

Fundamentals of nonassociative classical field theory

Abstract: A nonassociative classical field theory is constructed. Octonion algebra is studied. The octonion is represented as the sum of a quaternion and an associator. The octonion algebra is expanded and Lorentz group generators are specified in terms of octonion bases in one of the subalgebras. Lorentz vectors and spinors are constructed in the nonassociative algebra. The representation of the Lorentz group in terms of spin and the associator is obtained.

A possibility of a violation of a thermodynamic equilibrium in the early universe

Abstract: The evolution of superheated particles in the Friedmann universe is considered under the assumption of the asymptotic behavior of the scattering cross sections in the high-energy region. We show that there is no local thermodynamic equilibrium at early stages and conclude that the nature of cosmic rays can be explained on cosmological grounds.

Lattice dynamics and chemical binding in semiconducting compounds II-IV-V 2

Abstract: A review is given of experimental studies of infrared absorption, reflection, and Raman scattering of light on single crystals of I!--IV--V2 compounds. A rigid ion model is discussed as applied to the calculation of phonon spectra of ternary compounds with the chalcopyritetype lattice. In the simplest version of the model, short-range forces in the nearestneighbor approximation are given with the help of three parameters; Coulomb forces in the model of unpolarized ions are determined by two parameters. The dependence of phonon spectra on the ratio of cation masses is analyzed: a similarity between phonon spectra of ternary compound with similar cation masses and analogous binary compounds, placed in the Brillouin zone of chalcopyrite, as well as significant qualitative differences between spectra of binary and ternary semiconductors for a significant difference in cation masses is indicated. The calculated frequency density function, taken with a double scale g(2~), describes qualitatively the full symmetry component of the Raman scattering spectrum of second order. From the analysis of calculated elastic constants is has been established that in a number of ternary compounds a tendency is observed for decrease of elastic constants as the average atomic number is increased. Anisotropy of propagation of elastic waves in ternary compounds is analyzed. From the comparison of theoretical and experimental temperature dependences of the specific heat it has been shown that the Debye model does not describe experiment as well as the model which takes into account the real structure of the phonon spectrum.

Electrical and optical properties of electron-irradiated ZnGeP2

Abstract: The following conclusions are drawn from the reported study: The electrophysical properties of ZnGeP2 crystals and their optical transparency in the range hν

High energy electrons in the earth's radiation belts

Abstract: Special experiments performed aboard the space stations “Salyut-6”-“Soyuz”“Progress,” “Salyut-7”-“Soyuz T-13”-“Kosmos-1669,” and the artificial earth satellite “IK Bolgariya-1300” discovered, significant electron and positron fluxes with energies of more than decades of MeV in the earth's radiation belts. Spatial and angular characteristics of these fluxes have been studied. Study of the charge ratio of the electron-positron component has shown that it is electron-based. This indicates that in outer space near the earth some efficient mechanism capable of accelerating electrons to energies of more than decades of MeV exists.

Theoretical study of electron absorption spectra of pyronines and rodamine 110

Abstract: The quantum mechanical method of partial neglect of differential overlap is used to calculate the electron absorption spectra of three pyronines and rodamine 110. It is established that best agreement of theoretical and experimental data is obtained for a nonplanar conformation of the central pyrone cycle of molecules.

Calculation of the mixing energy of alloys by the method of a model electron-density functional. Ni-Al system

Abstract: Using a model electron-density functional the authors proposed earlier, calculations are performed for the ground state of alloys of the system Ni-Al to obtain characteristics such as mixing and ordering energies, equilibrium volumes per atom, and equilibrium charge transfers. The calculated results agree well with experimental data and make it possible to explain laws governing the formation of alloys of this system.

Canonical perturbation theory in statistical mechanics

Abstract: Hamiltonian formalism is used to develop a perturbation theory for the calculation of the mean values of arbitrary dynamic quantities.

Magnetoelastic acoustic emission in ferrosilicon single crystals

Abstract: The influence of magnetic-reversal effects on magnetoelastic acoustic emission (MAE) in single crystals of Fe + 3% Si cut in the [100], [110], and [111] directions is investigated, along with the relationship of these signals to the linear magnetostriction. It is shown that the MAE signals depend on the crystallographic directions and exhibit processes associated with rearrangement of the 90° domains throughout the entire volume of the ferromagnet.

Semiempirical determination of the vibronic constants of diatomic molecules. Optimal sets of constants a 3 Σ g + , e 3 Σ u + , d 3 Π u ± , and f 3 Σ u + of states of H 2

Abstract: The possibility of describing the vibronic electron levels of diatomic molecules by means of a limited set of molecular constants is investigated. For the example of the low triplet states of H2, it is shown that, in determining the set of vibronic constants of the given electron state and their covariance matrix, account must be taken of the specific features of the physical problem for which these constants are to be used. The optimal sets of constants obtained are significantly different from those in the literature. The reasons for the discrepancy are discussed.

Canonical quantization of gravity and quantum geometrodynamics

Abstract: A representation in the form of the Faddeev-Popov path integral is constructed for solving the equations of quantum geometrodynamics (QGD). It is shown that QGD is equivalent to canonical quantization of gravity in a unitary gauge. Given the state of the gravitational field on the initial Cauchy hypersurface, a wave function of closed universe is constructed so that it satisfies the QGD equations. Using the principles of canonical quantization, a probabilistic interpretation of this wave function is constructed in a fashion close to Everett's concepts of quantum mechanics.

Spinorial analysis and physical properties of fermions

Abstract: We study the formalism of covariant differentiation of a spinor field in a space of affine connection with an invariant metric. We find the most general formula for the coefficients of spinorial connection Γα consistent with the fundamental relationship between the space and spin (γαγβ + γβγα = 2gγαβ), and which is a generalization of the formula for the Fock-Ivanenko coefficients. The obtained formula contains additional terms describing the interaction between the spinor field and the scalar field, the vector field Aα, and the pseudovector field\(\mathop {\text{A}}\limits^ \vee _\alpha \) (presumably, the pseudotrace of the spacetime torsion). The existence of these interaction terms also follows from the analysis of spinor fields from the gauge-theoretical point of view. We show that the interaction between the spinor and pseudovector fields found in this paper substantially modifies the electrodynamics of spinor fields. As a result, the combined system of equations describing the dynamics of the vector (electromagnetic) and pseudovector fields is, unlike the Maxwell equations, symmetric with respect to the right-hand sides (sources). The source for the field strength tensor of the field comples Aα and\(\mathop {\text{A}}\limits^ \vee _\alpha \) is the vector current of the spinor field ¯gyγαψ, while the source for the dual field strength tensor is the pseudovector current of the spinor field ¯ψγαγ5ψ. It is suggested that the obtained interaction between the spinor and the scalar and pseudovector fields plays a role on a deeper level of matter structure —in quark and preon (subquark) systems.

Effect of the carrier temperature and the intensity of the recording beam on the energy of a photomagnetic recording of information

Abstract: If one takes into account thermally active transitions in the kinetic equations for photoinduced spin-reorientation transitions in the monocrystal Y3Fe5O12, it can be shown that the limiting temperature of the photomagnetic recording on which such an effect is based is a function of the intensity of the recording beam. This conclusion is confirmed experimentally.

Gallium arsenide avalanche-type S-diode based on a n+-π-ν-n structure

Abstract: The results are presented of an investigation of the electrical characteristics of avalanche S-diodes based on a new type of structure (+-π-ν-n), which is obtained by diffusing iron in GaAs with n = 1.1017 cm−3. The diodes have regions of S-type negative differential resistance (NDR), for both bias polarities and have a number of other features by comparison with diodes based on the π-ν-n structures with fused contacts. We discuss the mechanism for the formation of the NDR region of the voltage-current characteristics of the diode.

Probe method of determining the anisotropic velocity distribution of electrons in a plasma

Abstract: It is of interest to work out a method of analyzing the probe volt-ampere characteristics in the case when the electron velocity distribution function is no longer assumed to be isotropic; this is the subject of the present paper. The authors assume that there exists a preferred direction in the homogeneous infinite plasma, say in the direction of the z axis, and there is an applied electric field in this direction. In view of the cylindrical symmetry of the problem, the distribution function will be a function only of the velocity perpendicular to the preferred direction. They show that if one measures the dependence of the probe current on the stopping potential for a plane probe oriented perpendicular to the preferred direction and a cylindrical probe orientated parallel to the preferred direction, the longitudinal and transverse distribution functions can be found.

Investigating the effect of a magnetic field on beta decay

Abstract: The effect of an external magnetic field on theβ-decay process of a neutron is analyzed in detail. The spin effects within this process are studied, as is the final mass of the neutrino. Results of computer-based experiments are presented.

Linearized N=2 Poincaré supergravity in terms of SU(2)-extended superfields

Abstract: Linearized Poincare N=2 supergravity is presented in terms of SU(2)-extended superfields. Thus, the connection of SU(2)-extended superfields with the structure of auxiliary fields in N=2 supergravity is established.

Nature of the convective state of crystals in ``ultrahigh pressure + shear'' conditions

Abstract: The proposition is supported that the influence of ultrahigh pressure leads to the creation of a convective crystal state in which the entire ensemble of atoms is divided into strongly and weakly excited atoms. The first of these are found in a delocalized state, achieving the convective mass transfer regime, and the second are responsible for crystal structure.

Effect of vibrational kinetics of He 2 + ions on the afterglow of a discharge in helium

Abstract: A decaying weakly ionized helium plasma [ne=(0.2–1.1)·1011 cm−3, p=(40–70) mm Hg] was studied experimentally. It is shown that the experimental time dependences of the intensities of atomic lines and molecular bands in the afterglow phase can be explained if the vibrational kinetics of He2 + ions is included in the analysis. Analysis of the measurements shows that for ne ≲ 1011 cm−3 and Na ≳ 1018 cm−3 deexcitation of He2 + ions occurs primarily as a result of inelastic collisions with helium atoms. Based on the experimental data, an approximate value was obtained for the rate constants of the vibrational relaxation of molecular helium ions ≈10−16 cm3/sec. These results are used for making a qualitative analysis of the distribution of He2 + ions over the vibrational states in the discharge phase.

Ordering of atoms in 3d sublattice of the intermetallic quasibinary system Dy(Fe1−xMnx)2

Abstract: Methods of x-ray analysis and nuclear γ-resonance (Mossbauer effect) have been used to study the distribution of iron and manganese atoms in the intermetallic quasibinary system Dy(Fe1−xMnx)2, which is isostructural to the Laves phase C15. Ordering of atoms of transition metals has been found in 3d sublattice of intermetallic compounds Dy(Fe1−xMnx)2 with the formation of a triple superstructure having the stoichiometric composition Dy(Fe0·.25Mn0·.75)2.

“Mariya” experiment on the analysis of the electronpositron component of cosmic rays onboard the salyut 7, soyuz T-13, kosmos 1669 orbital complex

Abstract: Measurement results for electron and positron flows with energies in the range of 30–150 MeV are given for different latitudes in the area of the Brazilian anomaly that were made with the “Mariya” magnetic spectrometer on the Salyut 7, Soyuz T-13, Kosmos 1669 orbital complex.

Lagrangian formulation of a general Hamiltonian theory with constraints

Abstract: A Lagrangian formulation is constructed for a general Hamiltonian theory with constraints. A modification is proposed of the standard procedure of the “Hamiltonianization” of a Lagrangian theory in the case when the Lagrangian theory has primary constraints. The obtained results are used to establish the Lagrangian form of infinitesimally small canonical transformations in the Hamiltonian formalism.