scholarly journals Two-Field Cosmological Models and the Uniformization Theorem

2018 ◽  
pp. 233-241 ◽  
Author(s):  
Elena Mirela Babalic ◽  
Calin Iuliu Lazaroiu
Keyword(s):  
Cosmological Models ◽  
Uniformization Theorem

scholarly journals Anisotropic cosmological models in Horndeski gravity

2021 ◽  
Vol 103 (10) ◽  
Author(s):  
Rafkat Galeev ◽  
Ruslan Muharlyamov ◽  
Alexei A. Starobinsky ◽  
Sergey V. Sushkov ◽  
Mikhail S. Volkov
Keyword(s):  
Cosmological Models ◽  
Anisotropic Cosmological Models

Cosmic acceleration and stability of cosmological models in extended teleparallel gravity

Pramana ◽  
2021 ◽  
Vol 95 (1) ◽  
Author(s):  
A Y Shaikh ◽  
S V Gore ◽  
S D Katore
Keyword(s):  
Teleparallel Gravity ◽  
Cosmological Models ◽  
Cosmic Acceleration

scholarly journals Late Time Attractors of Some Varying Chaplygin Gas Cosmological Models

Symmetry ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 769
Author(s):  
Martiros Khurshudyan ◽  
Ratbay Myrzakulov
Keyword(s):  
Dark Energy ◽  
Gravitational Interaction ◽  
Chaplygin Gas ◽  
Cosmological Models ◽  
Late Time ◽  
Time Behavior ◽  
Coincidence Problem ◽  
Energy Models ◽  
Non Linear ◽  
Bayesian Machine Learning

The goal of this paper is to study new cosmological models where the dark energy is a varying Chaplygin gas. This specific dark energy model with non-linear EoS had been often discussed in modern cosmology. Contrary to previous studies, we consider new forms of non-linear non-gravitational interaction between dark matter and assumed dark energy models. We applied the phase space analysis allowing understanding the late time behavior of the models. It allows demonstrating that considered non-gravitational interactions can solve the cosmological coincidence problem. On the other hand, we applied Bayesian Machine Learning technique to learn the constraints on the free parameters. In this way, we gained a better understanding of the models providing a hint which of them can be ruled out. Moreover, the learning based on the simulated expansion rate data shows that the models cannot solve the H0 tension problem.

scholarly journals Geometries with mismatched branes

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Andreas Karch ◽  
Lisa Randall
Keyword(s):  
Boundary Conditions ◽  
Effective Action ◽  
Cosmological Models ◽  
Time Dependent ◽  
De Sitter ◽  
Stabilization Mechanism ◽  
New Class ◽  
Vacuum Solutions ◽  
Single Coordinate

Abstract We study Randall-Sundrum two brane setups with mismatched brane tensions. For the vacuum solutions, boundary conditions demand that the induced metric on each of the branes is either de Sitter, Anti-de Sitter, or Minkowski. For incompatible boundary conditions, the bulk metric is necessarily time-dependent. This introduces a new class of time-dependent solutions with the potential to address cosmological issues and provide alternatives to conventional inflationary (or contracting) scenarios. We take a first step in this paper toward such solutions. One important finding is that the resulting solutions can be very succinctly described in terms of an effective action involving only the induced metric on either one of the branes and the radion field. But the full geometry cannot necessarily be simply described with a single coordinate patch. We concentrate here on the time- dependent solutions but argue that supplemented with a brane stabilization mechanism one can potentially construct interesting cosmological models this way. This is true both with and without a brane stabilization mechanism.

scholarly journals The properties of Vlasov–Maxwell–Einstein equations and its applications to cosmological models

2020 ◽  
Vol 135 (5) ◽  
Author(s):  
Victor Vedenyapin ◽  
Nikolay Fimin ◽  
Valery Chechetkin
Keyword(s):  
Cosmological Models ◽  
Einstein Equations

Stability of LRS Bianchi type-I cosmological models in f(R, T)-gravity

2019 ◽  
Vol 19 (4) ◽  
pp. 055 ◽  
Author(s):  
Umesh Kumar Sharma ◽  
Rashid Zia ◽  
Anirudh Pradhan ◽  
Aroon Beesham
Keyword(s):  
Bianchi Type ◽  
Cosmological Models ◽  
Type I ◽  
Bianchi Type I
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