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Том 22, № 3 (2016)

Article

Virtual ring and quantum elements of a classical particle

Yefremov A.

Аннотация

The fractal equations of mechanics (quantum and classical) are clearly demonstrated to be definitions of an arbitrary potential on a fractal complex number valued surface. The developed approach helps us to show that a translational motion of any rotating compact object (point-like particle) can be equivalently represented by a specific rotation of a virtual ring described in terms of a fractal “wave function”, the model endowing the particle with a set of quantum characteristics including quantization of the ring’s space translation.

Gravitation and Cosmology. 2016;22(3):225-229
pages 225-229 views

Relativistic algebra of space-time and algebrodynamics

Kassandrov V., Rizcallah J.

Аннотация

We consider a manifestly Lorentz-invariant form L of the biquaternion algebra and its generalization to the case of a curved manifold. The conditions of L-differentiability of L-functions are formulated and considered as the primary equations for fundamental fields modeled with such functions. The exact form of the effective affine connection induced by L-differentiability equations is obtained for flat and curved manifolds. In the flat case, the integrability conditions of the connection lead to self-duality of the corresponding curvature, thus ensuring that the source-free Maxwell and SL(2,ℂ) Yang-Mills equations hold on the solutions of the L-differentiability equations.

Gravitation and Cosmology. 2016;22(3):230-233
pages 230-233 views

Chronometric measurement of orthometric height differences by means of atomic clocks

Kopeikin S., Kanushin V., Karpik A., Tolstikov A., Gienko E., Goldobin D., Kosarev N., Ganagina I., Mazurova E., Karaush A., Hanikova E.

Аннотация

We report on the experimental results of testing a new physical method of determination of the gravitational potential differences and orthometric heights by measuring the relativistic effect of gravitational redshift of frequency by means of atomic clocks. The experiment was performed in the Altai Mountains between two geodetic stations, Shebalino and Sieminski Pass, separated by about 850 meters in altitude. The measured mean value of the frequency shift caused by the change in the gravitational potential between the two stations is (δf/f0)grav = 7.980 × 10−14, with the dispersion σf = 7.27 × 10−15 referred to the time interval of the experiment.

Gravitation and Cosmology. 2016;22(3):234-244
pages 234-244 views

On exponential solutions in the Einstein–Gauss–Bonnet cosmology, stability and variation of G

Ernazarov K., Ivashchuk V., Kobtsev A.

Аннотация

A D-dimensional gravitational model with Gauss–Bonnet and cosmological terms is considered. When an ansatz with a diagonal cosmological metric is adopted, we find new examples of solutions for Λ Λ ≠ 0 and D = 8 with an exponential dependence of the scale factors, which describe expansion of our 3D factor-space and contraction of 4D internal space. We also study the stability of the solutions with static Hubble-like parameters hi and prove that two solutions with Λ = 0 in dimensions D = 22, 28, which were found earlier, are stable. For both solutions we find asymptotic relations for the effective gravitational constant.

Gravitation and Cosmology. 2016;22(3):245-250
pages 245-250 views

Modal series expansions for plane gravitational waves

Acedo L.

Аннотация

Propagation of gravitational disturbances at the speed of light is one of the key predictions of the General Theory of Relativity. This result is now backed indirectly by the observations of the behavior of the ephemeris of binary pulsar systems. These new results have increased the interest in the mathematical theory of gravitational waves in the last decades, and severalmathematical approaches have been developed for a better understanding of the solutions. In this paper we develop a modal series expansion technique in which solutions can be built for plane waves from a seed integrable function. The convergence of these series is proven by the Raabe-Duhamel criteria, and we show that these solutions are characterized by a well-defined and finite curvature tensor and also a finite energy content.

Gravitation and Cosmology. 2016;22(3):251-257
pages 251-257 views

On strong shock waves of annihilation

Golubiatnikov A., Lyuboshits D.

Аннотация

In the framework of special relativity theory, we give a piecewise-constant solution to the onedimensional problem of collision of a combination of particles and antiparticles with a flat wall which results in an annihilation shock wave. We assume that there is a complete transition of antimatter into the energy of remaining matter and outgoing radiation directed from the wall and, in its turn, separated from the incoming flow by a null rupture surface. The initial pressure in the mixture is neglected. We have constructed and investigated the Taub annihilation adiabat, including the Jouguet mode. Several limiting cases are considered as well, including a small concentration of antimatter, a small difference between the concentrations of matter and antimatter, the absence of directional radiation, and nonrelativistic velocity of the incoming flow.

Gravitation and Cosmology. 2016;22(3):258-263
pages 258-263 views

Macroscopic Einstein equations for a cosmological model with a λ term

Ignat’ev Y.

Аннотация

By averaging the Einstein equations over transverse gravitational perturbations we obtain a closed set of two ordinary differential equations describing the macroscopic cosmological evolution of the isotropic spatially flat Universe filled with gravitational radiation. We have found an asymptotic solution of the evolution equation for the gravitational perturbation amplitude. Substituting this solution to the Einstein equations averaged over gravitational perturbations, we obtain a single nonlinear ordinary differential second-order evolution equation with respect to the macroscopic scale factor. We have also found a solution of the evolution equation for the scale factor in the WKB approximation which analytically describes the process of transformation from the ultrarelativistic mode of cosmological expansion to an inflationary one.

Gravitation and Cosmology. 2016;22(3):264-269
pages 264-269 views

Excessive extrapolations in cosmology

Křížek M., Somer L.

Аннотация

The current standard cosmological model is based on the normalized Friedmann equation 1 = ΩMΛK, where ΩM is the mass density of dark and baryonic matter, ΩΛ the vacuum energy density, and ΩK is the curvature parameter. We show that the Friedmann equation was derived under excessive extrapolations from Einstein’s equations, which are not scale invariant and are “verified” on much smaller scales. We explain why these extrapolations are incorrect, why the unrestricted use of the term “verified” is questionable, and why dark matter may exist only by definition.

Gravitation and Cosmology. 2016;22(3):270-280
pages 270-280 views

Dilatonic (quasi-) black holes without scalar charge

Bronnikov K., Israpilov D.

Аннотация

We consider static, spherically symmetric configurations of electrically charged dust in Einstein-Maxwell-dilaton gravity where the Lagrangian contains the interaction term P(χ)FμνFμν with an arbitrary function P(χ). Unlike previous studies, we assume that the scalar field χ (which can be canonical or phantom) does not have a charge of its own and exists only due to this interaction. We discuss possible solutions to the field equations, in particular, those describing black holes (BHs) and quasi-black holes (QBHs). The latter are globally regular configurations whose size is very close to that of a BH of the same mass and which therefore are almost indistinguishable from BHs for a distant observer. Some general features are revealed, a family of explicitly integrable models is found, and some explicit examples are presented.

Gravitation and Cosmology. 2016;22(3):281-287
pages 281-287 views

Can gravity distinguish between Dirac and Majorana neutrinos?

Alavi S., Abbasnezhad A.

Аннотация

The interaction of neutrinos with gravitational fields in the weak field regime at one loop to the leading order has been studied by Menon and Thalappilil. They deduced some theoretical differences between the Majorana and Dirac neutrinos. Then they proved that, in spite of these theoretical differences, as far as experiments are concerned, they would be virtually indistinguishable. We study the interaction of neutrinos with weak gravitational fields to the second order (at two loops). We show that there appear new neutrino gravitational form factors which were absent in the first-order calculations, so from a theoretical point of view there are more differences between the two kinds of neutrinos than in the first order, but we show that likewise they are indistinguishable experimentally.

Gravitation and Cosmology. 2016;22(3):288-298
pages 288-298 views

Extra-relativistic effects and the Chandrasekhar limit

Sidharth B., Das A.

Аннотация

We endeavor to take into account the extra-relativistic effects in the mass-energy relation due to Einstein. We consider a modified mass-energy relation and consequently find a strict bound on the Chandrasekhar limit for a white dwarf star. We find that the said limit gets modified to a certain extent, and we have been able to find the maximum mass of a stable white dwarf star.

Gravitation and Cosmology. 2016;22(3):299-304
pages 299-304 views

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