scholarly journals Existence and stability of static spherical fluid shells in a Schwarzschild-Rindler–anti–de Sitter metric

2020 ◽  
Vol 102 (10) ◽  
Author(s):  
G. Alestas ◽  
G. V. Kraniotis ◽  
L. Perivolaropoulos
Keyword(s):  
De Sitter ◽  
Existence And Stability ◽  
Spherical Fluid ◽  
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.

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