Пространство, время и фундаментальные взаимодействия @stfi
Статьи журнала - Пространство, время и фундаментальные взаимодействия
Все статьи: 387
Inflationary models based on generalized exact cosmological solutions
Статья научная
This paper proposes a method for constructing an unlimited number of exact solutions to the equations of cosmological dynamics for the case of Einstein gravity and the teleparallel equivalent of general relativity. The exact cosmological solutions obtained within the framework of this approach imply complex types of evolution of the scalar field and the dynamics of the expansion of the universe. As an example, solutions to the equations of cosmological dynamics in the form of series are considered, each term of which and the entire series are exact solutions. It is shown that with a certain choice of parameters, the solutions obtained correspond to the correct dynamics of the expansion of the universe at various stages of its evolution
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Interacting spinor and electromagnetic fields in cosmology
Статья научная
Within the scope of a Bianchi type-I (BI) cosmological model we study the interacting system of spinor and electromagnetic fields. The corresponding system of Maxwell, Dirac and Einstein equations are obtained and solved. It was found that under such generalization nonlinear and massive spinor field can exist in a general BI space-time and give rise to different type of solutions depending on the choice of nonlinear and interacting terms.
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Investigation of the chiral cosmological model of f(R, oR) gravity
Статья научная
We study modified f (R, OR) gravity which can be reduced to the chiral cosmological model of the special type. Various types of cosmological solutions are considered based on exact analytical solutions, the slow-roll approximation, the superpotential method, the inclusion of additional material fields and reduction multi-field model to single-field one as well. Thus, this paper presents topical methods for analyzing cosmological models based on an effective multi-field interpretation of the proposed modified gravity.
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Статья научная
We present an extended version of the kinetic theory of the relativistic axionically active multi-component plasma, which is based on the inclusion of a unit time-like vector field, associated with the velocity of dynamic aether, into the scheme of interactions. The proposed extension of the plasma theory can be indicated as semi- phenomenological. This term means that master equations for the gravitational, electromagnetic, pseudoscalar (axionic) and vector (aetheric) fields are derived using the Lagrange formalism, the kinetic equations for the distribution functions are obtained by the methods of the covariant statistics, however, the relativistic forces acting from the listed fields on the plasma particles are reconstructed phenomenologically based on classical analogies. We consider this work as a first part of a trilogy; here we presented, first, the complete formalism of this extended theory, second, the classification of forces, third, the new concept of equilibrium states in the relativistic axionically - aetherically active plasma.
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Lie differential geometry Aufbau of the atoms and molecules
Статья научная
In previous PIRT conferences I have reported on a differential geometry structural make-up of the standard model of the elementary particles and the periodic system of the atoms following Marius Sophus Lie’s Ph.D. dissertation Over en Classe Geometriske Transformationer at Christiana (now Oslo) University in 1871. This thesis essentially describes Nature at the infinitesimal level it appears as by “a transition from a point to a straight line as element” both mathematically and materially of a coherent differential constitution. Under nucleosynthetic conditions its partial derivative square wave steps “of length equal to zero” goes into a space- filling modular “curve-net” formation. In the first generation, from the 10-15 meter size of the Nucleon radius, this is a bi-layer wave-packet accumulation of palindromic Bohr Aufbau configuration, whose repeated application like in an oriental tiling or carpet first outlines its pattern in the periodic table over the more than 10,000 times larger extension of the atom cross-section area. When an integral surface layer is covered by a full excursion of the knot returning to the origin, the train continues by moving upward the Nucleon shaft to a new facet of the crystal which retains the shape of its infinitesimal module and so can self-assemble into a polymeric nanostructure cluster of itself or molecular combinations with other atoms exactly and extensively as specified in established chemical formulas. This is here exemplified by some basic and more advanced organic compounds including the proteinogenic amino acids and DNA.
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Linear perturbations in the oscillating scalar field dark matter model
Статья научная
An oscillating scalar field acts like cold dark matter in the expanding Universe. Perturbations of the scalar field are considered through a hierarchy of time and spatial scales generated by the H/m ratio. The scalar field reproduces the CDM scenarios on all relevant cosmological scales and throughout the evolution of the Universe from the beginning of the oscillations. An effective cutoff of short wavelength perturbations occurs in both matter-dominated and radiation-dominated epochs.
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Motion in the gravitational field of a black hole in a synchronous coordinate system
Статья научная
Motion of a test body, or a particle, in the gravitational field of a black hole bordering dark matter is considered. The static gravitational field of extremely compressed matter is determined by solving the Einstein and Klein- Gordon equations in the synchronous coordinate system. An extremely compressed state of matter in the form of a condensate of a quantum Bose liquid is energetically more favorable than a degenerate Fermi gas. An important difference from the Schwarzschild and Kerr black holes is the absence of a singularity in the center. In a regular gravitational field, depending on the impact parameter, there are trajectories leading through the “event horizon” into the black hole, and not just passing by. At zero temperature, depending on the pair interaction of bosons, the condensate consists of components of a superfluid and an ordinary (non-superfluid) quantum liquid. The problem of the motion of a test body inside a black hole is solved analytically in the limiting case when, against the background of dominant gravity, friction with the non-superfluid component of the Bose condensate can be neglected.
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Non-vanishing cosmological constant effect in super-Poincare-invariant universe
Статья научная
In [1] we defined the Minkowski superspace 𝑆𝑀(4, 4|𝜆, 𝜇) as the invariant of the Poincare supergroup of supertransformations, which is a solution of Killing superequations. In the present paper we use formulae of super-Riemannian geometry developed by V. P. Akulov and D. V. Volkov [2] for calculating a superconnection and a supercurvature of Minkowski superspace.We show that the curvature of the Minkowski superspace does not vanish, and the Minkowski supermetric is the solution of the Einstein superequations, so the eight-dimensional curved super-Poincare invariant superuniverse 𝑆𝑀(4, 4|𝜆, 𝜇) is supported by purely fermionic stress-energy supertensor with two free real parameters 𝜆, 𝜇, and, moreover, it has non-vanishing cosmological constant Λ = 12/(𝜆2-𝜇2) defined by these parameters that could mean a new look at the cosmological constant problem
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Статья научная
Based on the concept of the dynamic aether emergence as a result of spontaneous polarization of the color aether, we consider the SU(2) symmetric theory of interaction of the gauge and axion fields in the framework of anisotropic cosmological model of the Bianchi-I type. We focus on the analysis of the non-Abelian analog of the U(1) symmetric model of axionically induced generation of the electric field in a magnetized medium.
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Nonlocal extension of relativistic non-equilibrium thermostatics
Статья научная
Based on the formalism of nonlocal extension of the Israel-Stewart causal thermodynamics [1] on the one hand, and on the formalism of the extended thermostatics [2] on the other hand, we propose the new model of nonlocal relativistic non-equilibrium thermostatics for description of the static spherically symmetric stellar systems. This nonlocal formalism operates with the pair of orthogonal four-vectors: one of them is the standard unit timelike medium velocity four-vector, the second one is the unit spacelike director. We derived the extended equation describing the profile of the non-equilibrium pressure, which can be indicated as the static analog of the Burgers equation known in classical rheology.
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On Weyl-Dirac gravitation theory and its development
Статья научная
Models of conformal gravitation that contain Lagrangians, which are linear on scalar curvature and with nonminimal connection with the scalar field, are discussed in this report. Theory of Weyl-Dirac gravitation has been reported in detail. A new version of conformal Lagrangian with two scalar fields is proposed, in which the Weyl vector is replaced with the vector which is transformed as a Weyl vector, but is not contained in Weyl connection. Weyl integrable space is the space of such model. The problem of describing a conformal stage in the evolution of the Universe on the basis of Friedmann metrics is considered within Weyl-Dirac gravitation theory with nonminimum connection with the real scalar field. Conformal invariant solutions for the scale factor are presented. It is demonstrated that quantum corrections to the trace of energy-momentum tensor are partially compensated by gauging the Dirac function, which results in the Lagrangian of the General Relativity theory.
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On conserved quantities for a moving black hole in TEGR
Статья научная
In the framework of the Teleparallel Equivalent of General Relativity (TEGR), where the field variables are tetrad components, mass and momentum for a moving (uniformly with respect to distant observers) Schwarzschild black hole (SBH) are constructed. A formalism developed by the authors earlier for constructing conserved quantities in TEGR, where currents and superpotentials are covariant with respect both to coordinate transformations and to local Lorentz rotations of tetrads is applied. This advantage has been reached by introducing inertial spin connection (ISC) and using the Noether theorem with preservation of a displacement vector in final expressions. A set of pairs (tetrad and related ISC) connected by smooth transformations we call as a “gauge”, it is the equivalence class. The quantity ISC is an external one, therefore we define it with making the use of the introduced by us generalized “turning off gravity” principle. But, even this a reasonable principle leads to different values of ISCs for the same tetrad that leads to different results. Here, on the example of the moving SBH we 1) demonstrate advantages of our fully covariant formalism, 2) study the ambiguity in definition of ISC as well. In calculations, we the use analogies with a moving mater ball in Minkowski space only in the “static gauge”. Expected mass and momentum have been obtained. Next we compare “static gauge” and “moving gauge”. It was found that they coincide. In the result, in the case of a moving SBH aforementioned ambiguity is absent because in both the cases the same mass and momentum are obtained.
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Статья научная
Higher-spin fields (for s≥2) are included into the spectrum of superstring theory, which describes gravitational interaction at an early stage of the Universe evolution and seem to be by natural candidates for describing Dark Matter. The note proposes a procedure for constructing Poincare-covariant Lagrangian cubic interaction vertices (previously known only in the light-cone formalism) for massless irreducible fields of higher integer and half-integer spins on Minkowski space-time of arbitrary dimension within the Becchi-Rouet-Stora-Tyutin (BRST) approach with an incomplete BRST operator. The consideration is based on the second order Lagrangian formulations for free totally-symmetric irreducible tensor and spin-tensor fields with Abelian gauge symmetries, which are deformed with the preservation of the number of physical degrees of freedom to a cubically interacting theory with non-Abelian gauge algebra. General cubic interaction for the fields with helicities n1+1/2, n2+1/2, s3, as in the Standard Model, contains two types of vertices to be BRST closed solutions of the generating equations, satisfying as well to gamma-traceless? traceless constraints and to the spin conditions.
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On the detection of high-frequency relic gravitational waves
Статья научная
The specificity of the spectrum of relic gravitational waves formed at the inflationary and post-inflationary stages of the evolution of the early universe is considered for cosmological models based on modified theories of gravity and Einstein gravity. The possibility of detecting high-frequency relic gravitational waves by using the process of converting gravitons into photons in a constant and alternating magnetic field is considered. The sensitivity of detectors of this type is compared with the sensitivity of other existing and prospective detectors of high-frequency gravitational waves. Based on the analysis of the sensitivity assessment of various types of high-frequency gravitational wave detectors, a conclusion is made about the prospects for direct verification of cosmological inflation models using gravitational-wave antennas.
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On the gravitational waves coupled with electromagnetic waves
Статья научная
A description is made of the process of excitation of coupled longitudinal-transverse gravitational waves during the propagation of a strong electromagnetic wave in a vacuum and when a standing electromagnetic wave exists in the Fabry-Perot resonator. It is shown that such waves lead to the appearance of transverse gravitational waves in empty space. It was established that two standing high-frequency electromagnetic waves in a Fabry-Perot resonator with close frequencies cause the appearance of a low-frequency transverse gravitational wave in empty space.
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On the temporal problem in quantum cosmology
Статья научная
The time problem in quantum cosmology has been considered in the framework of quantum geometrodynamics. Although time is not present in quantum cosmology explicitly, it emerges in classical cosmology. The classical world proves to be programmed on the quantum level.
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Статья научная
In this paper we present the results of a theoretical study of the trajectories of massive particles in the K¨ottler metric in view of the cosmological constant Λ. For both negative and positive signs of Λ a classification of trajectories is proposed, with entries based on different solutions of the trajectory equation, obtained by the expansion of the corresponding algebraic curve in Puiseux series. We also provide some specific types of trajectories which correspond to different values of the cosmological constant. In the case of negative values of the cosmological constant its upper limit is estimated from the galaxy rotation curves.
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Oscillating scalar fields as dark matter
Статья научная
The work considers oscillating scalar fields acting as cold dark matter in the expanding Universe. This behavior is inherent for both real and complex fields, and besides, the complex field reproduces the properties of cold dark matter even if the energy density per particle exceeds its mass.
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Physical basis of sensitivity of the Earth’s electromagnetic field to gravitation
Статья научная
Components of the Earth’s electric field vertical strength which are spectrally localized at the multiplied rotation frequencies of relativistic binary star systems, have significant amplitude and sharper spectral localization than at the other frequencies, have been discovered at the experimental material of multy-year time series of the Earth’s electric field strength in the infralow frequency band using eigenoscopy (second mixed moments eigenvectors’ amplitude spectra analysis at finite analysis span).
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Quasi-de Sitter solution in F(T, (T )2) teleparallel gravity
Статья научная
This paper considers the relevance of the quasi-de Sitter solution for the modified 𝐹(𝑇, (∇𝑇)2) teleparallel theory of gravity. The Hubble parameter is represented in the form: = 𝐻* + 𝜖𝑒-𝐵𝑡, where 𝐻*,𝐵 - 𝑐𝑜𝑛𝑠𝑡. The cosmological equations of the model with a perfect fluid are written for the following choice of function 𝐹: = 𝐴𝑇𝑛+𝜔(𝑇)∇𝜇𝑇∇𝜇𝑇. The evolution of matter density perturbations in the absence of pressure perturbations is considered.
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