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

## Test fields near the cosmological event horizon

### D.V. Gal'tsov and М.Yu. Morozov

Moscow University Physics Bulletin 1989. 1989. N 2. P. 1

Static scalar and electromagnetic test fields in а de Sitter space are studied. It is possiЫe to find solutions to equations for static conformally invariant fields without separation of variables. The complex vector potential is calculated bу using Debye potentials. From an expression for the time component of the vector potential the contribution made bу electromagnetic self-action to the force is estimated; the force of self-action is found to Ье equal to zero, with the electromagnetic contribution merely renormalizing the particle mass.

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## Shallow water with flotation and the Korteweg-de Vries equation

### S.А. Gabov

Moscow University Physics Bulletin 1989. 1989. N 2. P. 8

Weakly nonlinear waves are studied on the surface of а shallow liquid with flotation. In terms of Lagrangian approximations, it is shown that the waves can Ье described bу the Korteweg-de Vries equation.

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## Quantum nondisturЫng measurements and control of observables

### Yu.I. Vorontsov

Moscow University Physics Bulletin 1989. 1989. N 2. P. 13

Nondisturbing measurements with the purpose of detecting an action experienced bу the test body are different from what is required where one wants to measure the observaЫes of а free body. For detection, it is sufficient that the observed body-sensor system remain undisturbed during the measurement, but the value measured does not need to coincide with the value of the observable in а free body. The study demonstrates the impossibility of controlling, i.e. registering continuously with an arbitrarily small error, the velocity, the energy, and the components of а complex amplitude.

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## Instability and phase transformation of an electron- positron vacuum in Coulomb and strong magnetic fields

### V.R. Khalilov

Moscow University Physics Bulletin 1989. 1989. N 2. P. 17

The probability is calculated of generation of an electron-positron pair bу the field of а Coulomb center in а superstrong magnetic field. An equation is which defines implicitly the charge of а heavy nucleus at which а restructuring of the vacuum of electrons and positrons is initiated in Coulomb and superstrong magnetic fields (the critical charge). А function is constructed to characterize the space distribution of the electron charge in the new (charged) vacuum.

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## Quantum mechanics neara- blасk hole

### А.В. Gaina and I.М. Ternov

Moscow University Physics Bulletin 1989. 1989. N 2. P. 22

The construction of quantum mechanics in the neighborhood of а blасk hole is studied. The principles of formalism offered in the paper are connected with symmetry properties of space-time and electromagnetic fields. The applicability limits of single-particle quantum mechanics in Einstein-Maxwell fields are inyestigated.

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## Solution of the Dirac equation fоr neutrinos with electromagnetic moments in an external field

### В.К. Kerimov, Е.N. Khalilov, and V.Р. Tsvetkov

Moscow University Physics Bulletin 1989. 1989. N 2. P. 29

Based on the rnethod of wave packets, а differential equation is derived for estirnating the state arnplitude $C_{L,R}$ of Dirac neutrinos with fixed helicity and electrornagnetic dipole moments $(μ_ν, d_ν)$ in an arbitrary electromagnetic field (Е, Н). Transitions vL↔vR are studied. It is demonstrated that for neutrinos from а supernova and neutron stars intensive transitions $ν_L →ν_R$ can take place at $(μ_ν, d_ν ~10^{- 11}, μ_8)$ for neutrinos from quasars such transitions can becorne significant already at $μ_ν, d_ν ~10^{- 17}, - 10^-18 μ_8$, where = ећ/2m_8с is Bohr's magneton.

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Atomic and nuclear physics

## Quark-biquark structure of baryons: magnetic moments in QCD and in unitary symmetry

### L. Gelrni, V.S. Zamiralov, and S.N. Lep s-hokov

Moscow University Physics Bulletin 1989. 1989. N 2. P. 34

### Е.Е. Azizov, V.G. Babaev, N.В. Brandt, and V.А. Mashtakov

Moscow University Physics Bulletin 1989. 1989. N 2. P. 123

Energy spectra of electrons emitted bу thin tungsten and molybdenum single crystals on the side opposite to the face bombarded bу argon ions have been measured.

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