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

## High-Q resonators and nonperturbing quantum measurements

### F.Уа. Khalili

Moscow University Physics Bulletin 1989. 1989. N 4. P. 1

The limiting potential of schernes for nonperturbing quantum measure ments of the energy of а traveling electromagnetic wave based on energy accumulation in а high- Q resonator is explored. The influence of the reflection of quanta from а resonator is considered. It is shown that the necessary condition for precise nonperturЫng measurement is inclusion of the resonator in the transmission line so that only the signal - mode field is incident there. Entry of the field of any no - load modes - even in the zero state - into the resonator is impermissible.

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## Reliability of parametrically specified model of measurements

### I.V. Mitin and А.I. Chulichkov

Moscow University Physics Bulletin 1989. 1989. N 4. P. 7

The role of model concepts for the interpretation of experimental results is investigated. The problem of refining the model parameters on the basis of the concept of the reliability of the model is for mulated. Relations are obtained for calculating the local reliability with fixed values of the model parameters.

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## Optimal control of three- stage hot - pressing process

### V.В. Glasko, А.N. Tikhonov, and М.К. Trubetskov

Moscow University Physics Bulletin 1989. 1989. N 4. P. 14

А simple model of а three-stage hot-pressing model is proposed, describing inductive heating and the subsequent thermophysical processes on the basis of the effective characteristics of the porous medium. А pressing quality criterion is introduced, and the optimization problem is formulated as а variational proЫem. On the basis of а computational experiment, methods for its solution are analyzed, and the basic result is given.

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## Analog of phase space for the sine- Gordon equation

### А.G. Popov

Moscow University Physics Bulletin 1989. 1989. N 4. P. 20

An interpretation of surfaces of constant negative curvature as analogs of classical phase spaces is proposed. А methodological principle is formulated for the phenomena described bу the sine-Gordon equation.

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## One- dimensional hydrogen atom

### V.В. Gostev, V.К. Peres - Fernandes, А.R. Frenkin, and G.А. Chizhov

Moscow University Physics Bulletin 1989. 1989. N 4. P. 24

The problem of nonrelativistic one-dimensional particle motion in а Coulomb attractive field which has been under investigation for а long time is subjected to examination. On the basis of the physical principles that the energy levels are independent of the choice of length scales, that there is no Clauder effect, and tbat there are no bound states in the repulsive field, а self-consistent expansion of the Hamiltonian of а one-dimensional hydrogen atom with uniquely de fined parity-nondegenerate levels and а stable ground state is found. New expressions are found for the even wave functions.

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Atomic and nuclear physics

## Ground state of two- dimensional two-electron atomic systems

### V.V. Komarov, А.М. Popova, V.G. Airapetyan, and А.М. Gadzhiev

Moscow University Physics Bulletin 1989. 1989. N 4. P. 28

The spectral properties of the Schrodinger operator of two-dimensional two-electron atomic systems are investigated. Tirring estimates are obtained for the ground-state energy. Within the framework of the variational method and the Hylleraas method, the ground-state energy is calculated in the first and third approximations.

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## Change in emission properties of W- Re alloy after $\gamma$ irradiation

### V.А. Mashtakova, Р.В. Ryaryaev, and А.А. Salomatin

Moscow University Physics Bulletin 1989. 1989. N 4. P. 32

In а cylindrical vacuum diode, emission properties of wires of W-Re alloy irradiated bу у quanta of energy 1.З MeV are investigated. It is shown that the work function determined Ьу the total-current method and the Richardson straight-line method is increased as а result of irradiation and further annealing.

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## Elementary processes in photoionized- discharge plasma in nitrogen with additions of $NH_3$ and Хе

### А.V. Zabolotnykh and V.В. Saenko

Moscow University Physics Bulletin 1989. 1989. N 4. P. 36

The plasmochemical processes and dynamics of plasma breakdown in а volume discharge initiated bу hard UV radiation are analyzed. Thanks to the use of high- energy radiatiori quanta, it is possible to broaden the choice of readily ionizaЫe impurities. It is shown that it is expedient to use NH_3 and Хе to excite quasi- continuous discharge in CO_2 and СО laser media, respectively. The necessary photoionization pulse- repetition frequency is determined.

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## Standard quantum limit in measuring small fo r ces using а tunnel sensor

### V.Р. Mitrofanov and V.N. Yakimov

Moscow University Physics Bulletin 1989. 1989. N 4. P. 42

А device for recording srnall forces frorn the change in arnplitude of oscillator vibrations is analyzed; this change in amplitude is rnea-· sured bу rneans of а displacernent sensor based on the tunnel effect. The conditions of attainrnent of the standard quanturn lirnit for the rneasured force are deterrnined.

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## Parametric video amplifier with frequency - selective no ise compression

### А.V. Gusev and V.V. Kulagin

Moscow University Physics Bulletin 1989. 1989. N 4. P. 48

The quantum constraints on the sensitivity in а parametric video amplifier of reflective type with an additional element - а channel for forming an inverse wave in the compressed state - are investigated.

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## Double acoustooptical Bragg scatter ing of light

### V.В. Voloshinov, V.N. Parygin, and В. Traore

Moscow University Physics Bulletin 1989. 1989. N 4. P. 53

Experimental results are given on the conditions of anisotropic diffraction in the propagation of two acoustic waves of different fre quency in the same direction in а crystal. The dependence of the intensity of the Bragg maxima оп the amplitude and frequency of the acoustic waves is measured.

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Optics and spectroscopy

## Phase modulation of pulses in dye lasers with synchronous pumping

### D.Р. Krindach and V.I. Novoderezhkin

Moscow University Physics Bulletin 1989. 1989. N 4. P. 59

Conditions of steady mode synchronization in dye lasers with synchronous pumping are investigated theoretically, taking account of phase modulation. Analytical solutions are obtained for the pulse length and the chirp par ameter with arЫtrary detuning of the wavelength relative to the center of the amplification line. The results of experimental investigation of the phase modulation and of in- resonator and extraresonator compensation of the chirp in а continuous dye laser are outlined.

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## Modeling photosynthesis light curves

### N.О. Belogrudov, V.А. Karavaev, and А.К. Kukushkin

Moscow University Physics Bulletin 1989. 1989. N 4. P. 66

On the basis of а model taking account of the features of the primary processes of photosynthesis, а theoretical description of the light curves of photosynthesis is developed. In model experiments, light curves are obtained for different values of the electron-transport rate constant and distributions of the absorbed light energy between photosystems. The results are discussed in connection with known experimental data.

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## Fiber- optical sensor of spatial coherence of radiation

### D.V. Baranov, М.I. Belovolov, I.V. Zhurilova, S.К. Isaev, А.Р. Kryukov, and А.V. Kuznetsov

Moscow University Physics Bulletin 1989. 1989. N 4. P. 73

А simple, compact sensor of spatial coherence based on а Y-type fiber directional coupler. The signal at the sensor output is created as а result of interference of the light beams captured Ьу the lightguide cores. The sensor permits spatial separation of the investigated plane of the beam and the recording apparatus, the use of electronic processing of the signal, and measurement of the radius of curvature of the laser-beam wavefronts.

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Acoustics and molecular physics

## Kinetic equation of one- dimensional acoustic turbulence

### О.V. Rudenko and V.А. Khokhlova

Moscow University Physics Bulletin 1989. 1989. N 4. P. 77

А Boltzmann-type kinetic equation is obtained for the distribution function of the parameters of а random sequence of weak shock waves, taking account of the motion of discontinuous fronts and their pair combinations. On the basis of accurate solution of this equation, the evolution of the intensity spectrum of an ensemЫe of shock waves with а finite width of the front is investigated.

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Solid state physics

## Temperature distribution at the surface of ultrasound- deformed sodium- chloride crystals according to thermovisual data

### G.М. Zinenkova, Е.V. Pala , N.А. Tyapunina, N.Р. Novikov, and Yu.V. Zharkoi

Moscow University Physics Bulletin 1989. 1989. N 4. P. 83

The temperature distribution at the surface of samples deformed bу ultrasound at frequencies of 10^5 Hz and amplitudes of relative deformation ε^О ~ 10^{-5}-10^{-4) is investigated in situ. It is shown that the region close to the stress antinode is beated bу no more than 10 К with respect to room temperature. А difference is seen in the temperature variation in the region of elastic deformation ε^О and with plastic deformation.

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## Influence of electron injection from Si into $SiO_2$ on the electrical instability of metal- dielectric - semiconductor structures

### Yu.N. Kasumov and S.N. Kozlov

Moscow University Physics Bulletin 1989. 1989. N 4. P. 88

The laws of electrical instability of silicon metal-dielectric-semiconductor structures are studied as а function of the quantity of electrons injected from silicon into the $SiO_2$ layer and the temperature. It is shown that the electrical stability of inj ection-degraded structures is determined bу the superposition of two effects: the appearance of an additional mobile ionic charge and the generation and recharging of "slow" electron states.

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Theoretical and mathematical physics

## Vibrations in laminar elastic - viscous media

### G.N. Medlvedev and В.I. Morgunov

Moscow University Physics Bulletin 1989. 1989. N 4. P. 93

Systems of nonlinear integrodifferential equations describing mechenical vibrations in media that consist of layers with both elastic and viscous properties are considered. An asymptotic investigation of such systerns based on averaging is outlined.

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## Self-polarization of electrons moving in а spiral magnetic undulator

### V.G. Bagrov, V.V. Belov, М. Ternov, and А.Yu. Trifonov

Moscow University Physics Bulletin 1989. 1989. N 4. P. 96

Self-polarization of the electron spin in spontaneous emission accompanying electron motion in а spiral magnetic undulator is studied. It is shown that the quantitative characteristics - the degree of polarization and the relaxation time - differ from the analogous characteristics in synchrotron radiation.

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## Centrallу symmetric gravitational source against the background or а nonmetric field

### А.L. Mikhailov

Moscow University Physics Bulletin 1989. 1989. N 4. P. 100

А quasi-Schwarzschild metric is obtained for а centrally syrnmetric gravitational source against the background of а nonmetric field. The constraint on the nonmetric behavior in the solar system is found from the results of analyzing classical tests for gravitational theory.

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## Quantum electrodynamics with an additional compact coordinate

### D.А. Slavnov

Moscow University Physics Bulletin 1989. 1989. N 4. P. 103

For the example of quantum electrodynamics, a procedure for the elimi­nation of UV divergences conserving locality and relativistic and BRS invariance in all stages is formulated.

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## Correlation function of stochastic motion of two-dimensional nonlinear oscillator

### Р.V. Elyutin and V.G. Korolev

Moscow University Physics Bulletin 1989. 1989. N 4. P. 106

А method is presented for the approximate calculation of correlation functions for Hamiltonian systems performing stochastic motion. An example is considered for the Pullen-Edmonds model, which is in good agreement with computer-modeling data.

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## Weakli correlating polynomials for the description of atmospheric aberrations

### K.V. Shishakov and V.I. Shmal'gauzen

Moscow University Physics Bulletin 1989. 1989. N 4. P. 110

Polynornials orthonormalized to annular regions, giving weakly correlated coefficients of the expansion of atrnospheric aberrations, taking account of the external scale of turbulence, are obtained. They are compared with Zernik polynqrnials.

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Solid state physics

## Oscillator-model calculation of diamagnetic susceptibility of dyes

### М.Yu. Nikolaev and S.S. Semenov

Moscow University Physics Bulletin 1989. 1989. N 4. P. 117

On the basis of the oscillator model, the diamagnetic susceptibility of dyes is calculated. It is shown that the results obtained depend strongly on the number of $\pi$- electrons.

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## Internal friction of alloys of the terbium -dysprosium system in the paramagnetic region close to the Neel temperature

### G.I. Kataev, М.R. Sattarov, and V.V. Shubin

Moscow University Physics Bulletin 1989. 1989. N 4. P. 121

At frequencies of $\sim$ 1 kHz and temperatures T = 78-320 K in fields of up to 14.5 kOe, the internal friction $Q^{-1}$ of Tb-Dy alloys is studied. Above the Neel point, a maximum of $Q^{-1}(T)$ with large temperature hysteresis is observed; this is associated with the disappearance of antiferromagnetic short-range order.

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