Faculty of Physics
M.V.Lomonosov Moscow State University
Theoretical and mathematical physics

## A gage-invariant Lagrangian for a Poincare group

### A.P. Demichev, N.F. Nelipa

Moscow University Physics Bulletin 1987. 42. N 3. P. 1

A previously proposed method is used to analyze the possibility of building a gage-invariant action for a Poincare group which satisfies the physical requirements. It is shown that such an action cannot be built in the case of precise symmetry, but can be built with spontaneous disruption of symmetry. In this case the possibility arises of the existence of massive vector particles which correspond to the gage fields of the translation subgroup.

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## A method for calculating vertex type Feynman integrals

### E.E. Boos, A.I. Davydychev

Moscow University Physics Bulletin 1987. 42. N 3. P. 6

A method is proposed for precise calculation of the dimensionally regularized apex type Feynman diagrams. This metod is used to find expressions for a class of massless vertex integrals which expand the number of precisely calculable Feynman diagram in the quantum field theory and which are of interest for calculations in gage theories and in studying processes involving participation of elementary particles at high energies.

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## Observable post-Newtonian effects caused by static, even-power metric Finsler functions

### A.K. Aryngazin, G.S. Asanov

Moscow University Physics Bulletin 1987. 42. N 3. P. 11

Orbital gravitational effects and the signal delay effect, caused by static, even-power Finsler metrics, are studied. These metrics generalize the ordinary static Riemann (quadratic, M = 2) metrics for the case of static biquadratic, etc. (M = 4, 6, ... ) metrics. The upper limits for specific Finsler parameters are found using observation data about the shift of the perihelion and signal delay.

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## Collision of relativistic heavy ions

### D.A. Slavnov

Moscow University Physics Bulletin 1987. 42. N 3. P. 17

The results of the assumption that at high energies nucleus-nucleus scattering passes through a stage of valon plasma are examined. The multiplicities of secondary hadrons are calculated in the fragmentational field of an incident beam as functions of the minimal value of the scaling variable.

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## Reduction of images distorted by a turbulent atmosphere

### Yu.P. Pyt'ev, A.I. Chulichkov, N.M. Chulichkova

Moscow University Physics Bulletin 1987. 42. N 3. P. 22

Reduction methods are examined in application to processing images acquired with observation through a layer of turbulent atmosphere. The purpose of the processing is to represent the images in a form in which they can be recorded using a near-ideal instrument without the atmosphere. The influence of the statistical characteristics of the medium on the result of the processing is investigated and requirements for additional information about the subject of observation for achieving an assigned reduction quality are formulated.

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## The problem of mathematical processing of experimental results from semiconductor nuclear radiation detectors

### I.V. Mitin, T.D. Shodmonkulov

Moscow University Physics Bulletin 1987. 42. N 3. P. 28

The use of a reduction method for processing experimental results from semiconductor detectors in the presence of a priori information about the nature of the measuned signal is examined. The possibility of a dialog mode when processing the experimental results is indicated, when the researcher has the capability of acquiring more precise and reliable results with parametric assignment of the a priori information.

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## The equivalence of passive-input-output devices

### V.I. Shestakov

Moscow University Physics Bulletin 1987. N 3.

The relation of equivalence of passive input-output devices is identified in terms and symbols of the statements of calculation of three-digit Bochvar logic and the basic properties of this relation are deduced.

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## Using three-value logic in the theory of dimensionality of physical values

### V.I. Shestakov

Moscow University Physics Bulletin 1987. 42. N 3. P. 41

The use of calculation of statements of three-value Bochvar logic in the theory of dimensionality of physical values is examined. A "draft" of the theory of dimensionalities, whose basic postulate is the formula which symbolically expresses the statement: "If the equality V = W makes sense, then the equality [VJ] = [WJ] of the [VJ] and [WJ] dimensionalities of the physical values V and W is true," is presented. The question about the dimensionalities of physical values in the Gauss and ISU (International System of Units) is briefly examined.

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## The effect of equipment noises on the sensitivity of a rapid frequency SQUID [superconducting quantum interference device] in the "out of plateau" mode

### A.V. Gusev

Moscow University Physics Bulletin 1987. 42. N 3. P. 48

The actual sensitivity of a radio frequency SQUID, determined by fluctuations in the electrical degree of freedom and the preamplifier with selection of the working point between neighboring plateaus, is theoretically investigated. A standard method for describing regenerative systems, which operate in a conditionally stable mode, is used to describe the signal and noise characteristics of SQUID in this mode. Formulas are found for calculating the actual sensitivity of a SQUID with amplitude-phase demodulation of the output signal, and a comparison with the traditional "on plateau" mode is performed.

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## Beam instability in a relativistic plasma

### A.N. Matveev, P.A. Polyakov, M.A. Tasev

Moscow University Physics Bulletin 1987. 42. N 3. P. 52

The question about wave excitation in a one-dimensional relativistic plasma by a low density electron beam with low thermal scattering of the particles is investigated. The increment of excitation of plasma waves is found for frequencies similar to a low-frequency intrinsic mode. The influence of thermal scatter of the beam electrons on the frequency of oscillations and the increment in instability of the excited wave is analyzed.

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Optics and spectroscopy

## The effect of electron-hole correlations on the luminescence of crystalline phosphor with traps

### A.N. Vasil'ev, V.V. Mikhailin, I.V. Ovchinnikova

Moscow University Physics Bulletin 1987. 42. N 3. P. 57

A model of a crystalline phosphor with traps with two channels of electron-hole recombination (direct and through the luminescence center) is examined. The dependence of the quantum output of luminescence of one of the channels on the dispersion length of the electron and hole during the hot relaxation stage is established. The dependence of the quantum output of luminescence on the energy of the incident photons, the intensity of the incident light, and its temperature is constructed.

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## Evaluating the magnitude of nonuniform expansion of the fluorescence spectrum of rhodamine 6G in glycerin

### I.A. Struganova

Moscow University Physics Bulletin 1987. 42. N 3. P. 62

The formation of an imbalanced distribution of fluorescing centers at frequencies of a 0-0 transition in a dipole solvent-dye system and the subsequent transformation of the imbalanced distribution into balanced over a time of $\tau_R$ is examined. The magnitudes of nonuniform expansion of the fluorescence spectrum and the time $\tau_R$ for a solution or rhodamine 6G in glycerin are estimated on the basis of the measured relations of the time for fading of the fluorescence of this solution.

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## Light scattering in polaritons in a biaxial crystal near the binormal

### T.V. Laptinskaya, A.N. Penin, M.V. Chekhova

Moscow University Physics Bulletin 1987. 42. N 3. P. 67

The features of the frequency-angle spectrum of scattering in polaritons in a biaxial crystal, which form when the wave vector of the polariton is oriented near the binormal, are examined. When the scattering plane deviates from the plane containing the binormal the scattering branch is disintegrated along the wave vector; the corresponding distribution in intensity in this case may be explained by the change in the magnitude of the convolution of the quadratic susceptibility with unit vectors of polarization of three interacting waves with rotation of the unit vector of polariton polarization.

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## Application of the Monte Carlo method for investigating energy migration in complex organic compounds

### A.A. Demidov

Moscow University Physics Bulletin 1987. 42. N 3. P. 74

The Monte Carlo method is used to investigate exciton migration in complex organic compounds. The Monte Carlo method used in the work does not require a priori limitations on the parameters of the compounds and uses only the spatial structure of the compounds and the spectroscopic characteristics of the molecules which comprise them. The potential of the method is demonstrated in an example of phycobilicom - a composite part of the light collecting antenna of some photosynthesizing organisms.

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## Coherent phenomena in a "band-level" system in a fluctuating field

### V.Yu. Finkel'stein, V.A. Namiot

Moscow University Physics Bulletin 1987. 42. N 3. P. 81

The role of radiation fluctuations in the suppression of periodic "surge-like" returns of a system to the ground state with excitation from it into a band of discrete levels is studied. It is shown that the suppression is determined by the ratio of the width of the radiation line to the width of the excitation region into the band. With slow frequency fluctuations the suppression may be weakened, while with resonance on the edge of the band and amplitude fluctuations it, on the contrary, rises sharply.

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Solid state physics

## The role of collective effects in the formation of V ultraviolet spectra of rare-earth ions in crystals

### L.I. Devyatkova, A.A. Druzhinin, O.N. Ivanova, V.V. Mikhailin, S.P. Chernov

Moscow University Physics Bulletin 1987. 42. N 3. P. 89

The evolution of V ultraviolet spectra of $BaY_2F_8$ crystals as the yttrium ions are replaced by ions of rare-earth elements of the ytterbium subgroup is investigated. Even transitions into the paired d-states, which correspond to the rare-earth ions which are close neighbors in the Bravais lattic yttrium, take part in the formation of the spectrum at comparatively low concentrations of the substituting ions. At greater concentrations the nature of the spectrum is determined by the presence or absence of exciton-like f-d states which are split off from the conduction zone.

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Geophysics

## Phase transformations and differentiating material in the Earth's mantle

### M.V. Avdulov

Moscow University Physics Bulletin 1987. 42. N 3. P. 93

Separation of the Earth's mantle into mineralogical fractions at a temperature below the solidus point of the rock occurs with periodic changes in temperature under the effects of polymorphous transformations. Estimations of the influence of the Bjerknes forces and the force of radial pressure on the kinetics of the process are cited.

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Theoretical and mathematical physics

## Interaction between a particle ensemble and planar wave field with variable parameters

### A.M. Khapaev, I.V. Ponomarev

Moscow University Physics Bulletin 1987. 42. N 3. P. 98

A functional which describes the change in the energy of an electron ring as a function of an external field is constructed to analyze interaction between a particle ensemble and a planar wave field with variable parameters. One of the possible modes of its change is examined to the extremum.

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## Is the $\lambda x^{-2}$ barrier penetrable?

### V.B. Gostev, A.R. Frenkin

Moscow University Physics Bulletin 1987. 42. N 3. P. 102

Physically preferable self-adjoint expansion of a Hamiltonian with a property of $s(s+ 1)х^{-2}, — 1/2 < s < 1/2$ is selected. It is used to indicate a method for continuation through point $x=0$ of solutions of the Schr$\stackrel{..}{o}$edinger equation with a potential with the same property. After this standard rules are used to find the unambiguous coefficient of passage T of the $\lambda x^{-2}$ barrier (pit). In light of the uniformity of the Hamiltonian this coefficient in the absence of the additive barrier $h\delta (x)$ is not a function of energy. The coefficient T for a Coulomb barrier (pit) is cited.

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Atomic and nuclear physics

## Electron capture into excited states with collisions between nuclei and atoms

### Yu.A. Shurygina, V.S. Senashenko, Ya.A. Teplova

Moscow University Physics Bulletin 1987. 42. N 3. P. 106

A method for calculating the cross sections of electron capture, developed with consideration of Coulomb asymptotic behavior of the wave functions of an electron, is used to analyze electron capture into excited states of a colliding particle in regions of intermediate and high energies.

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## Measuring light radiation intensity using a parametron

### S.E. Zhmurov, V.F. Marchenko, I.T. Trofimenko

Moscow University Physics Bulletin 1987. 42. N 3. P. 111

The experimental characteristics of a digital photocapacitance sensor of weak light radiation, in which planar $Аl—SiO_2\cdot Si_3N_4—Si$ structures are used, are cited. The radio frequency part of the sensor is a parametric oscillator built on the basis of a balance circuit with metal-dielectric-semiconductor structures, one of which is illuminated by light. A change in the intensity of the light changes the balance of the circuit; the intensity is proportional to the probability of fall out of one of the stable phases of the subharmonic with multiple triggering of a periodically excited parametric loop oscillator.

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Optics and spectroscopy

## The influence of anomalous dispersion on the characteristics of a ring laser

### N.V. Kravtsov, E.G. Lariontsev, A.N. Shelaev

Moscow University Physics Bulletin 1987. 42. N 3. P. 115

The features of the frequency and amplitude characteristics of ring lasers, which contain a resonantly absorbing medium inside the resonator, are investigated. It is established that the presence of a medium with anomalous dispersion leads to a substantial increase in the dependence of the intrinsic generation frequencies and the difference in frequencies of opposed waves of the ring laser on the perimeter of the resonator and the magnitude of the optical nonmutuality. It is shown that stationary generation becomes unstable in a ring laser in the region of negative values of the group speed of light.

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Acoustics and molecular physics

## Nonlinear orientation elasticity of a nematic liquid crystal

### Yu.V. Vasil'ev, E.F. Kuritsyna

Moscow University Physics Bulletin 1987. 42. N 3. P. 119

The possibility of quantitative estimation of the first nonlinear correction to the law of elasticity of a nematic liquid crystal is shown.

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## A method for calibrating receiving antennas

### V.V. Kravtsov, P.K. Senatorov

Moscow University Physics Bulletin 1987. 42. N 3. P. 121

A method is proposed for determining the beam pattern of a receiving antenna based on data acquired with sequential irradiation of the antenna by a point source from different points in space. The method is based on mathematical modeling of the diffraction process.

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Solid state physics

## Transition into a "dipole glass" state in the $(NH_4)_2(BeF_4)_{1-x}(SO_4)_x$ system

### B.A. Strukov, P.S. Smirnov, L.P. Reshetnikova

Moscow University Physics Bulletin 1987. 42. N 3. P. 123

The temperature relation of heat capacity of a solid: solution of $(NH_4)_2(BeF_4)_{0,63}(SO_4)_{0,37}$ is investigated in a temperature range of 80-300 K. A proposal about the existence of a new mechanism of dipole glass formation in solid solutions of ferrielectrics, which is associated with the spatial deorientation of the polar directions in the initial components of the mixture, is advanced on the basis of an analysis of the nature of the temperature behavior of the heat capacity of the cited compound.

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## The structure and magnetic properties of compounds of the $Dy_{1-x}Gd_xAl_2$ system

### M.M. Abd-el-Aal, A.S. Il'yushin, A.V. Pechennikov, Yu.R. Sharapov, V.I. Chechnerikov

Moscow University Physics Bulletin 1987. 42. N 3. P. 126

The magnetic properties of compounds of a $Dy_{1-x}Gd_xAl_2$ system, where $x$ = O; 0.2; 0.4; 0.6; 0.8; and 1.0, are investigated in a temperature range of 4.2-1000 K. An X-ray phase analysis is performed. The magnetic moments of ferromagnetic and paramagnetic regions are identified. The dependence of the ferromagnetic and paramagnetic Curie point on concentration is shown. It follows from the acquired experimental results that ferromagnetic exchange interaction between atoms of the rare-earth metals, which is monotonically dependent on $x$, dominates in the $Dy_{1-x}Gd_xAl_2$ system.

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