Poincare Gauge Theory Of Gravity Research Articles

THE TRAUTMAN PROBLEM OF INFORMATION TRANSFER, THE PROBLEM OF ENERGY TRANSFER BY GRAVITATIONAL WAVES AND THE STATUS OF THE POINCARE GAUGE THEORY OF GRAVITY

The transfer of information is one of the problems of the propagation of gravitational waves in connection with the prospect of the possible use of high-frequency gravitational waves for the creation of space communications. The requirements for information transfer are formulated in the form of the Trautman problem, which defines the conditions under which gravitational waves invariantly transfer the information contained in them. The second problem of the propagation of gravitational waves is the problem of energy-momentum transfer, which is not solved in general relativity, but can be solved in the punch of the gauge theory of gravity, for which the “criterion of strong localization of the energy-momentum of the gravitational field” is formulated. The features of two approaches in the Poincare gauge theory of gravity are discussed.

Decrease of the effective cosmological constant in the Poincare gauge theory of gravity with a scalar field

Cosmological consequences of the Poincare gauge theory of gravity are considered. An effective cosmological constant depending from the Dirac scalar field is introduced. It is proved that at the super-early Universe, the effective cosmological constant decreases exponentially from a huge value at the Big Bang to its extremely small value in the modern era, while the scale factor sharply increases and demonstrates inflationary behavior. This fact solves the well-known “cosmological constant problem” also in the Poincare gauge theory of gravity.

General Poincare Gauge Theory Cosmology

For the quadratic Poincare gauge theory of gravity (PG) we consider the FLRW cosmolo- gies using an isotropic Bianchi representation. Here the considered cosmologies are for the general case: all the even and odd parity terms of the quadratic PG with their respective scalar and pseudoscalar parameters are allowed with no a priori restrictions on their values. With the aid of a manifestly homogeneous and isotropic representation, an effective La- grangian gives the second order dynamical equations for the gauge potentials. An equivalent set of first order equations for the observables is presented. The generic behavior of physical solutions is discussed and illustrated using numerical simulations.

A study of plane torsion waves in the Poincaré gauge theory of gravity

The variational equations of the gravitational field in Riemann-Cartan space are derived in the external forms formalism using the method of Lagrange indefinite multipliers for the Poincare gauge theory of gravity with quadratic Lagrangians in the general form. The structure of the irreducible parts of torsion propagating in the form of plane waves in Riemann-Cartan spacetime is investigated.

Spinor coupling to the weak Poincare gauge theory of gravity in three dimensions

Minimal coupling of a Dirac field to gravity with the most general non-propagating torsion is considered in (1+2)-dimensions. The field equations are obtained from a lagrangian by a variational principle. The space-time torsion is calculated algebraically in terms of a quadratic spinor condensate plus coupling coefficients. Firstly we give circularly symmetric rotating exact solutions that collapse to $AdS_3$ geometry in the absence of the Dirac condensate. Secondly we investigate a BTZ-like solution.

Massless Modes of Lorentz Gauge Fields in Poincare Gauge Theory of Gravity: The Case with + 2a/3= -2a/3= + 3a/2=0

The Lorentz gauge fields in Poincare gauge theory of gravity are considered in a linear approximation. Propagators of Lorentz gauge fields are examined to show the existence of massless modes of these fields. Our consideration is restricted to the case with the condition a + 2a/3 = β- 2a/3 = γ + 3a/2 = 0, where a, β, γ and a are parameters appearing in the gravitational Lagrangian. We find that four ghost-free theories have normal modes and that each of the theories has a mode with helicity-parity 1 + or 1-. We also demonstrate a duality of the approximated Poincare gauge theories in this case.

COSMOLOGICAL CONSTANT AND GRAVITATIONAL REPULSION EFFECT I: HOMOGENEOUS MODELS WITH RADIATION

Within the framework of the minimum quadratic Poincare gauge theory of gravity in the Riemann-Cartan spacetime, we study the influence of gravitational vacuum energy density (a cosmological constant) on the dynamics of various gravitating systems. It is shown that the inclusion of the cosmological term can lead to gravitational repulsion. For some simple cases of spatially homogeneous cosmological models with radiation, we obtain nonsingular solutions in the form of elementary functions and elliptic integrals.

Experimental restrictions on spin-spin interaction in gauge gravity

The article deals with the Poincare gauge theory of gravity with the most general Lagrangian quadratic in curvature and torsion. We consider three special cases of this model. Two effects are calculated within these models: the hyperfine energy level splitting of the hydrogen atom and the interaction between polarized photons in a sodium vapor. We find that none of these models allows one to estimate model constants consistently.

Matching and Junction Conditions in the Poincare Gauge Theory of Gravity with Quadratic Lagrangian

We find conditions satisfied by discontinuities of gravitational and matter fields on an interface between two media, and discuss their application to the boundary problem for the field equations. The spherically symmetric case is considered in more detail

Gravitational equations in space-time with torsion

Various representations of equations of gravitational theories in space-time with torsion are considered. Special attention is paid to the case of quadratic Poincaré gauge theory of gravity. Advantages of each representation are discussed. The complete algorithm for calculation of gravitational equations in the framework of the most efficient formalism of spinor-valued exterior forms is presented.

Asymptotic Anti-De Sitter Conditions for Poincare Gauge Theory

We find conditions on the ten parameters of the Poincare Gauge Theory of Gravity which are necessary for solutions with an asymptotically anti-de Sitter metric and asymptotically constant Riemann-Cartan curvature or asymptotically constant torsion

Group of Paths, Holonomy Groups and Nonintegrable Phase Factors in \overlinePoincar e Gauge Theory of Gravity

grou~, we examin~ t~e group of pa.!~~i' holonomx groups and nonintegrable phase factors: (i) Conslderng the seml·dlrect product EPo=[Path]®P o, where [Path] stands for the group of paths in a four· dimensional Minkowski space, we construct a linear representation of EPo by defining the action:of this group on the fiber bundle P. The parallel transports in P, the holonomy group and the nonintegrable phase factor are all described by this representation. (ii) Correpsonding discussions are given for the affine frame bundle over the spacetime. Remarkable is the fact that the motions of a point and of a vector are both described by the nonintegrable phase factor. Discussions can be easily extended to the case in which Poincare gauge and Yang· Mills gauge fields coexist. Nonintegrable phase factors are equally important in Poincare gauge theory of gravity as well as in the Yang·Mills gauge theory.

Spaces with flat symmetry in poincar� gauge theory of gravity

A Taub space is considered in the Poincare gauge theory of gravity. It is shown that the torsion tensor has four nonvanishing components, which can be split into two independent pairs S010, S011, and S230, S231. The analysis of the gravitational field equations leads to the conclusion that in this case only a flat space-time with torsion is possible, and that its metric coefficients and the components of the torsion tensor are described by a wave equation.

A gauge theory of gravitation based on a specific Lagrangian

The paper is devoted to the presentation of a specific Lagrangian for the Poincare gauge theory of gravity. Interesting and useful properties of the gauge theory of gravitation based on this Lagrangian are briefly outlined.

A Note on \overlinePoincare Gauge Theory of Gravity: Additional Comments

In a series of papers/H) one (T. K.) of the present authors has proposed a theory, which has been named a Poincare gauge theory of gravity. In Refs. 3)~5), special relativistic limits and conserved quantities have been discussed. In considerations of generators in Refs. 3) and 5), however, the coordinate transformations have been restricted to those which agree with Poincare transformations ,at spatial infinity. In view of the invariance of our action under the general coordinate transformations, we give the following discussion in the present note:*) (i) The coordinate transformation (III· 7 ·1) discussed in Refs. 3) and 5) is extended to**)

Asymptotic symmetry and conserved quantities in the Poincare gauge theory of gravity

The structure of the generators of the asymptotic Poincare symmetry in the general R+T2+R2 theory of gravity is obtained by using the Hamiltonian formalism. It is shown that a correct treatment of the generators leads to the appearance of certain surface terms, which determine the values of the gravitational energy, momentum and angular momentum.

Spontaneous symmetry breaking by gravitational field and regular isotropic models with torsion

The effect of spontaneous symmetry breaking by gravitational field is investigated in the case of open homogeneous isotropic models within the framework of the Poincare gauge theory of gravity. It is shown that this procedure permits the construction of cosmological models that are regular in the metric and the torsion.

Exterior calculus on the computer: The REDUCE-package EXCALC applied to general relativity and to the Poincaré gauge theory

The computer algebra system REDUCE has recently been enriched by a package on exterior calculus. Here we apply the EXCALC package to the calculation of quantities within the Poincare gauge theory of gravity, general relativity being included in this scheme as a spcial case. Thereby we simplify and streamline earlier results found by means of tensor-analytical REDUCE calculations.

ISO(3, 1) gauge theory of gravity

We establish a Poincare affine frame bundle, give the operation of gauge groupISO(3, 1) on the fiber bundle, obtain the action of the Poincare gauge theory of gravity, and advance two sets of gravitational gauge field equations of the theory. We discuss some special cases of the theory.

Bianchi identities and the automatic conservation of energy-momentum and angular momentum in general-relativistic field theories

Automatic conservation of energy-momentum and angular momentum is guaranteed in a gravitational theory if, via the field equations, the conservation laws for the material currents are reduced to the contracted Bianchi identities. We first execute an irreducible decomposition of the Bianchi identities in a Riemann-Cartan space-time. Then, starting from a Riemannian space-time with or without torsion, we determine those gravitational theories which have automatic conservation: general relativity and the Einstein-Cartan-Sciama-Kibble theory, both with cosmological constant, and the nonviable pseudoscalar model. The Poincare gauge theory of gravity, like gauge theories of internal groups, has no automatic conservation in the sense defined above. This does not lead to any difficulties in principle. Analogies to 3-dimensional continuum mechanics are stressed throughout the article.