Principle of the existence of space and the de Sitter metric

1990 ◽  
Vol 83 (3) ◽  
pp. 671-674
Author(s):  
V. K. Mal'tsev
Keyword(s):  
De Sitter ◽  
De Sitter Metric

The influence of cosmological constant in temperature oscillations of a gas moving close to circular geodesic

2019 ◽  
Vol 34 (20) ◽  
pp. 1950109
Author(s):  
Leandro Cesar Mehret ◽  
Gilberto Medeiros Kremer
Keyword(s):  
Theoretical Model ◽  
Cosmological Constant ◽  
Constant Term ◽  
Circular Motion ◽  
Small Displacement ◽  
De Sitter ◽  
Normal Coordinates ◽  
Temperature Oscillations ◽  
Circular Geodesic ◽  
De Sitter Metric

The aim of this work is to analyze and to verify the effects of the charge and cosmological constant on the temperature oscillations that occur in a gas in a circular motion close to geodesic under the action of a Reissner–Nordström–de Sitter metric. The temperature oscillations are determined from Tolman’s law written in Fermi normal coordinates for a comoving observer. The temperature oscillations are calculated for a theoretical model obtained in the literature. Comparing the different configurations analyzed, it is possible to verify that the cosmological constant term causes a small displacement in the oscillation peaks. We also calculated the ratio between frequencies for some particular cases of the Reissner–Nordström–de Sitter metric and verified that the cases with null cosmological constant are closer of the 3/2 value found in QPOs. In another hand, the addition of the cosmological constant causes a direct increase of the ratio between frequencies.

Kerr-NUT-de Sitter Metric and Step-by-Step Extension Method

1997 ◽  
Vol 14 (12) ◽  
pp. 885-888
Author(s):  
Xu Dian-yan ◽  
Qiu Zong-yan
Keyword(s):  
De Sitter ◽  
Extension Method ◽  
De Sitter Metric

scholarly journals Inhomogeneous compact extra dimensions and de Sitter cosmology

2020 ◽  
Vol 80 (10) ◽  
Author(s):  
Kirill A. Bronnikov ◽  
Arkady A. Popov ◽  
Sergey G. Rubin
Keyword(s):  
Scalar Field ◽  
Cosmological Constant ◽  
Field Distribution ◽  
Extra Dimensions ◽  
Factor Space ◽  
De Sitter ◽  
Extra Factor ◽  
De Sitter Metric

AbstractIn the framework of multidimensional f(R) gravity, we study the possible metrics of compact extra dimensions assuming that our 4D space has the de Sitter metric. Manifolds described by such metrics could be formed at the inflationary and even higher energy scales. It is shown that in the presence of a scalar field, it is possible to obtain a variety of inhomogeneous metrics in the extra factor space $${{\mathbb {M}}}_2$$ M 2 . Each of these metrics leads to a certain value of the 4D cosmological constant $$\varLambda _4$$ Λ 4 , and in particular, it is possible to obtain $$\varLambda _4 =0$$ Λ 4 = 0 , as is confirmed by numerically obtained solutions. A nontrivial scalar field distribution in the extra dimensions is an important feature of this family of metrics. The obtained solutions are shown to be stable under extra-dimensional perturbations.

scholarly journals Kottler spacetime in isotropic static coordinates

2021 ◽  
Author(s):  
Rahulkumar Solanki
Keyword(s):  
Elliptic Functions ◽  
Time Dependent ◽  
Refractive Indices ◽  
Coordinate Transformations ◽  
De Sitter ◽  
Canonical Coordinates ◽  
Jacobian Elliptic Functions ◽  
Null Geodesics ◽  
Isotropic Coordinates ◽  
De Sitter Metric

Abstract The Kottler spacetime in isotropic coordinates is known where the metric is time-dependent. In this paper, the Kottler spacetime is given in isotropic static coordinates (i.e., the metric components are time-independent). The metric is found in terms of the Jacobian elliptic functions through coordinate transformations from the Schwarzschild-(anti-)de Sitter metric. In canonical coordinates, it is known that the unparameterized spatially projected null geodesics of the Kottler and Schwarzschild spacetimes coincide. We show that in isotropic static coordinates, the refractive indices of Kottler and Schwarzschild are not proportional, yielding spatially projected null geodesics that are different.

The Effect of Cosmic Vacuum on the Properties of Scalar Field

2015 ◽  
Vol 61 ◽  
pp. 58-62
Author(s):  
Ali Nadhim Sabbar ◽  
G.N. Shikin
Keyword(s):  
Periodic Solution ◽  
Gravitational Field ◽  
Field Equation ◽  
Scalar Field ◽  
Asymptotic Representation ◽  
Accurate Solution ◽  
De Sitter ◽  
Synchronization Time ◽  
Scalar Field Equation ◽  
De Sitter Metric

The thesis explains the effect of cosmic vacuum of gravitational field on properties of scalar field equation. In the space-time plane, the scalar field equation has periodic solution φx,y,z,t=Acos (kx±ωt). Consideration the cosmic vacuum of gravitational field (using De Sitter metric in its synchronization time) the equation of scalar field will have accurate solution in form of Beseel function. By using the asymptotic representation, the periodic solution (t→±∞) will vanish. The scalar field equation when t→+∞ will decrease regularly, and when t→-∞ it will increasing fluctuate.

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