Showing papers on "Friedmann–Lemaître–Robertson–Walker metric published in 1982"
TL;DR: In this paper, the Brans-Dicke equations with the cosmological constant were studied and exact solutions in the spatially flat Robertson-Walker metric in the matter-dominated universe were presented.
Abstract: The Brans-Dicke equations with the cosmological constant are studied. We present exact solutions in the spatially flat Robertson-Walker metric in the matter-dominated universe. A brief discussion on this cosmology is given.
56 citations
TL;DR: In this paper, a new solution of the Einstein-Maxwell field equations is presented and the material content of the field described by this solution is a perfect fluid plus sourceless electromagnetic fields.
Abstract: A new solution of Einstein-Maxwell field equations is presented. The material content of the field described by this solution is a perfect fluid plus sourceless electromagnetic fields. The metric of the solution is explicitly written. This metric is examined as a possible representation of Kerr-Newman metric embedded in Einstein static universe. The Kerr-Newman metric in the background of Robertson-Walker universe is also briefly described.
15 citations
TL;DR: For the cosmological field equations of the Poincare gauge theory, a universal appearance of the Friedmann equations of general relativity was shown in this article, and exact solutions with torsion were presented.
13 citations
9 citations
TL;DR: In this article, exact solutions of the field equations with a cosmological constant were presented, and the space-time considered here is a Bianchi type I and includes an electromagnetic field.
8 citations
TL;DR: In this paper, the unusual correspondence of a closed cosmological model and the field equations of the Brans-Dicke theory with general relativity is discussed, and the meaning of the correspondence is also discussed briefly from the Machian point of view.
Abstract: The unusual correspondence of a closed cosmological model and the field equations of the Brans-Dicke theory with general relativity is discussed. This cosmological model is correspondent to the Einstein universe and the Brans-Dicke scalar field behaves like the cosmological term in the field equations when the coupling parameterω is very small. The meaning of the correspondence is also discussed briefly from the Machian point of view.
5 citations
TL;DR: In this article, a Friedmann-Robertson-Walker (FRW) model is studied in the new scalar-tensor theory of gravitation proposed by Schmidt et al. and exact solutions are given, and at least in one case it is possible to obtain a model with oscillation between finite limits.
Abstract: A Friedmann-Robertson-Walker (FRW) model is studied in the new scalar-tensor theory of gravitation proposed by Schmidt et al. There is an assumption of a particular functional relationship between the cosmological expansion factor of the FRW model and the scalar field. Exact solutions are given, and it is observed that at least in one case $k=\ensuremath{-}1$ it is possible to obtain a model with oscillation between finite limits.
3 citations
TL;DR: In this paper, a two-time scale method for solving the perturbed field equation was used to study the evolution of helicity-0 waves (density waves) on the FRW cosmological background.
Abstract: Presents a study of evolution of helicity-0 waves (density waves) on the FRW cosmological background by using a two-time scale method for solving the perturbed field equation. The kinetic description is adopted by means of the collisionless Liouville equation self-consistently coupled with Einstein's equations. The wave packets obtained are solutions of the shift type. The effects of the expansion of the background (geometrical effects) are contained in these solutions and lead to a power law for the scale factor instead of an exponential law in time. The rate of growth is obtained from dispersion relations which are studied in the case of a cold gravitational plasma. For large wavenumber q the Newtonian dispersion relation is recovered as is the time behaviour of the Newtonian solution, and for vanishing q the behaviour of the relativistic hydrodynamics for the pressureless case is also recovered. It is found that in a relativistic treatment of the cold gravitational plasma, the smaller q becomes the faster the instability grows.
3 citations
01 Jan 1982
TL;DR: In this paper, it is suggested that this puzzle can be resolved by assuming that quantum state of the universe is not chosen at random but contains only states with a very large Euclidean 4-volume.
Abstract: The apparent cosmological constant is measured to be zero with an accuracy greater than that for any other quantity in Physics. On the other hand one would expect a large induced cosmological constant unless the various contributions from symmetry breaking, etc., were balanced against each other to better than 1 part in 1040 It is suggested that this puzzle can be resolved by assuming that quantum state of the universe is not chosen at random but contains only states with a very large Euclidean 4-volume. In this situation the actual value of the cosmological constant is unobservable. There are solutions of the Einstein equations with a large cosmological constant which appear nearly flat on large length scales but which are highly curved and topologically complicated on very small length scales. Estimates are made of the spectrum of these topological fluctuations and of their effects on the propagation of particles.
2 citations
TL;DR: The long-standing problem of cosmological constants arising from unified theories in particle physics and from purely gravitational phenomena, on the other side, is studied in the framework of the gauge-covariant theory of gravitation as discussed by the authors.
Abstract: The long-standing problem of cosmological constants arising from unified theories in particle physics, on the one side, and from purely gravitational phenomena, on the other side, is studied in the framework of the gauge-covariant theory of gravitation. The notion of system of units depending upon the corresponding interaction as well as the systematics provided by the GCTG could solve the problem. We may have zero Einstein cosmological constant but nonzero Linde-type cosmological constants. Both are related through a transformation of units.
1 citations
TL;DR: In this paper, the authors analyzed the finite temperature λφ4 model in the Robertson Walker metric, taking into consideration spontaneous symmetry breaking, particle production and symmetry recovery through phase transition under a high temperature, and found that it is possible to have a cosmological model free of singularities.