Bimetric Theory Of Gravitation Research Articles

The stability of «Q balls» in Rosen’ bimetric theory of gravitation

The approximate solution of a SO2 theory of two scalar fields in the bimetric theory of gravitation is discussed. Coleman's suggestion that suchQ matter can be stabilized by an internal rotation in SO2 space leads to stability criteria for theQ matter before the breaking of the SO2 global symmetry. The two distinct masses lead to two different criteria of stability for theQ ball. The problem of the cosmological constant is left as an unanswered and pressing question in the bimetric theory.

Accretion disks in the bimetric theory of gravitation: Strong gravity sensitivity of the inner disk edge

Optically thin accretion disks with bremsstrahlung are calculated in the bimetric theory of gravitation. The obtained results are compared with the corresponding results in Einstein's theory. The gravitational sensitivity of the inner disk edge, situated in the strong field of a central compact object, is an argument in support of the assertion that the accretion disk as a whole could be determined by strong gravity effects.

Rotating bodies in the bimetric theory

AbstractThe article deals with the physical parameters of rotating bodies in the bimetric theory of gravitation in second approximation in the angular velocity. The authors present the results of calculations carried out for configurations whose state of matter is described by monoparametric equations of ideal neutron gas and relativistic polytropes.

On the conformal transformations of metrics in Rosen's bimetric gravitation theory

The conformal transformations of the background metric are considered and the transformed expressions of the gravitational energy and of the gravitational field equations are obtained. The conditions of conservation of the nongravitational energy are formulated with respect to the transformed metric. Then the background and the physical metrics are both subjected to transformations and the relationship between the corresponding conformal factors analyzed, particularly in the case of conserved nongravitational energy.

Some harmonic maps on pseudo-Riemannian manifolds

Rosen's bimetric theory of gravitation, when equipped with a flat background metric, is known to be realized as a harmonic mapping of Minkowski spacetime into a certain homogeneous space. This paper develops and exploits these facts to provide four classes of explicit solutions to Rosen's field equations. These four classes form the elements from which more general solutions may be formed by a type of superposition. It is also shown how spherical gravitational waves may be explicitly built into these solutions.

On conformally related fields in Rosen's bimetric gravitation theory

It is shown that the gravitational energy generation vector is conformally invariant. The necessary and sufficient condition for the conformai invariance of the gravitational field equations is found. The conformal transformations of two simple nongravitational energy tensors are considered. It is shown that the conformal factor for metrics conformal to the background is the solution of a simple differential equation.

Accretion disks in bimetric theory of gravitation. A strong field test of general relativity?

AbstractThe sensitivity of accretion disk models with respect to its inner boundary conditions, being located in the strong gravity region of a highly compact central body, is used to discuss a possibility of strong field tests of gravitation via compact source observations. Within the bimetric theory of gravitation the optically thin bremsstrahlung model is calculated as an example for this possibility. Using this model to describe the innermost region of the “bimetric disk”, significant differences with respect to the corresponding results in Einstein's theory were found. The more massiv and compact “bimetric disk” radiates softer with higher luminosity.

Stationary axisymmetric gravitational fields in the bimetric theory

Stationary axisymmetric fields are considered in the framework of Rosen's bimetric theory of gravitation. Analytic solutions in the approximation quadratic in the angular velocity are found outside the mass distribution. A method is proposed for finding the metric within the mass distribution and determining the internal structure and the integrated parameters of rotating objects in which the state of the matter is described by a single-parameter equation.

Anisotropic fluid distributions in bimetric general relativity

Static and spherically-symmetric solutions of the field equations in the bimetric theory of gravitation are obtained for isotropic and anisotropic distributions of matter when the physical metric admits a one-parameter group of conformal motions. The solutions agree with Einstein's general relativity for physical systems comparable to the size of the Universe, such as the solar system.

On the singularity in Rosen's bimetric theory of gravitation

It is shown that Rosen's bimetric theory of gravitation also has a Schwarzschild-type singularity. The radius of the singularity-the gravitational radius-is defined by the secondary massM1. Simultaneously it is shown that only those configurations are stable, which are located in the range of central densities corresponding to the increasing branch of theM1 =M1(ρc) curve.

Strong-field effects and time asymmetry in general relativity and in bimetric gravitation theory

The concepts underlying our present theoretical understanding of the radiative two-condensed-body problem in general relativity and in bimetric gravitation theory are critically reviewed. The relevance of the 1935 Einstein-Rosen “bridge” article is emphasized. The possibility (first suggested by N. Rosen, for the linearized approximation) of extending to gravity the Wheeler-Feynman time-symmetric approach is questioned.

Slowly rotating superdense configurations in Rosen's bimetric theory of gravitation

In the limits of the Bimetric Theory of Gravitation the equations of axial-symmetric gravitational field, describing the field of rotating configurations, are obtained and examined. The analytical solutions of these equations out of configurations are found. The equations are solved numerically in the first approximation in the angular velocity for the configurations consisting of the real baryon gas (cf. Sahakian, 1972). The moments of inertia of these configurations in BTG are calculated. It is shown that the equations and the appropriate solution, obtained by Falik and Opher (1979), are incorrect.

Slow rotation in the bimetric theory of gravitation

Field equations and their exterior solutions in the approximate quadratic in angular velocity are obtained for stationary axisymmetric gravitational fields. The problem of rotating configurations consisting of a degenerate real baryon gas is solved in the framework of bimetric theory, and the results are compared with analogous ones in general relativity. It is shown that the results obtained by Falik and Opher (1979) are incorrect. 15 references.

A gauge-covariant bimetric theory of gravitation and electromagnetism

The Weyl theory of gravitation and electromagnetism, as modified by Dirac, contains a gauge-covariant scalar β which has no geometric significance. This is a flaw if one is looking for a geometric description of gravitation and electromagnetism. A bimetric formalism is therefore introduced which enables one to replace β by a geometric quantity. The formalism can be simplified by the use of a gauge-invariant physical metric. The resulting theory agrees with the general relativity for phenomena in the solar system.

External magnetic field of a static spherically symmetric star in Rosen's bimetric theory of gravitation

In this brief paper we present a complete exact solution for the external magnetic field (dipolar at infinity) of a static magnetic star on the spherically symmetric background metric solution of Rosen's bimetric theory of gravity. Unlike in general relativity the field is well behaved throughout the manifold except at $r=0$, and thus allows one to consider the field for stars collapsed beyond $2m$.

Spherically symmetric fields in Rosen's bimetric theories of gravitation

By means of bimetric Killing vectors two spherically symmetric fields are investigated: (i) the time-dependent one in Rosen's flat-background bimetric theory; and (ii) the energy-preserving in Rosen's cosmological-background bimetric theory withk = 1. In the first case a wave behavior of the field is present. In the second case a time evolution is obtained for fields, created by insular systems of constant energy. These phenomena are typical for bimetric theories of gravitation.

Bimetric killing vectors and generation laws in bimetric theories of gravitation

The concept of bimetric Killing vectors is introduced. The set of these vectors allows one to define global mechanical integrals for matter and field separately, and to get conservation laws for the matter quantities and generation laws for the field quantities. It is possible to predict what physical spaces of high mobility are contained in a certain variant of a bimetric theory. The procedure is developed in the framework of Rosen's bimetric theories of gravitation, but it may be applied to a wide class of bimetric theories.

Production of primordial helium and deuterium as a strong-field test of gravitation theory

view Abstract Citations (2) References (18) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Production of primordial helium and deuterium as a strong-field test of gravitation theory Falik, D. ; Opher, R. Abstract It is noted that a fundamental weak-field test of a theory of gravitation is that it satisfies the Parameterized Post-Newtonian (PPN) parameters determined by solar system experiments. The production of primordial helium and deuterium in the big bang is seen as a test of a gravitational theory in the strong-field approximation, and it is suggested that this test be used along with the PPN parameters. The test is applied to Rosen's bi-metric theory of gravitation, and for a wide class of models of this theory it is shown that essentially no primordial helium or deuterium is produced. Publication: The Astrophysical Journal Pub Date: January 1981 DOI: 10.1086/158560 Bibcode: 1981ApJ...243....8F Keywords: Big Bang Cosmology; Deuterium; Gravitation Theory; Helium; Nuclear Fusion; Relativity; Astronomical Models; Bimetric Theories; Field Strength; Gravitational Fields; Astrophysics full text sources ADS |

Stability of superdense stars in the bimetric theory of gravitation

Calculations of superdense star models in the Rosen bimetric theory of gravitation are presented. There is a family of ‘quark stars’ whose members are probably stable even if their masses do not exceed the maximum mass of neutron stars.

Rotating neutron stars in the bi-metric theory of gravitation

Rotating neutron stars in the bi-metric theory of gravitation