scholarly journals Bianchi cosmologies with anisotropic matter: Locally rotationally symmetric models

2011 ◽  
Vol 240 (7) ◽  
pp. 636-669 ◽  
Author(s):  
Simone Calogero ◽  
J. Mark Heinzle
Keyword(s):  
Locally Rotationally Symmetric ◽  
Anisotropic Matter ◽  
Rotationally Symmetric ◽  
Bianchi Cosmologies

scholarly journals Quantum Kasner transition in a locally rotationally symmetric Bianchi II universe

2021 ◽  
Vol 104 (2) ◽  
Author(s):  
Ana Alonso-Serrano ◽  
David Brizuela ◽  
Sara F. Uria
Keyword(s):  
Locally Rotationally Symmetric ◽  
Rotationally Symmetric

scholarly journals Averaging generalized scalar field cosmologies II: locally rotationally symmetric Bianchi I and flat Friedmann–Lemaître–Robertson–Walker models

2021 ◽  
Vol 81 (6) ◽  
Author(s):  
Genly Leon ◽  
Sebastián Cuéllar ◽  
Esteban González ◽  
Samuel Lepe ◽  
Claudio Michea ◽  
...  
Keyword(s):  
Scalar Field ◽  
Nonlinear Dynamical Systems ◽  
Perturbation Parameter ◽  
Time Dependent ◽  
Late Time ◽  
De Sitter ◽  
Time Dynamics ◽  
Locally Rotationally Symmetric ◽  
Bianchi I ◽  
Rotationally Symmetric

AbstractScalar field cosmologies with a generalized harmonic potential and a matter fluid with a barotropic equation of state (EoS) with barotropic index $$\gamma $$ γ for the locally rotationally symmetric (LRS) Bianchi I and flat Friedmann–Lemaître–Robertson–Walker (FLRW) metrics are investigated. Methods from the theory of averaging of nonlinear dynamical systems are used to prove that time-dependent systems and their corresponding time-averaged versions have the same late-time dynamics. Therefore, the simplest time-averaged system determines the future asymptotic behavior. Depending on the values of $$\gamma $$ γ , the late-time attractors of physical interests are flat quintessence dominated FLRW universe and Einstein-de Sitter solution. With this approach, the oscillations entering the system through the Klein–Gordon (KG) equation can be controlled and smoothed out as the Hubble parameter H – acting as time-dependent perturbation parameter – tends monotonically to zero. Numerical simulations are presented as evidence of such behavior.

On symmetries and conservation laws of some spacetimes in f(R, T) gravity

2019 ◽  
Vol 34 (36) ◽  
pp. 1975003
Author(s):  
Ashfaque H. Bokhari ◽  
A. H. Kara ◽  
B. Gadjagboui
Keyword(s):  
Conservation Laws ◽  
Detailed Analysis ◽  
Bianchi Type ◽  
Type I ◽  
Noether’S Theorem ◽  
Bianchi Type I ◽  
Plane Symmetric ◽  
Locally Rotationally Symmetric ◽  
Rotationally Symmetric ◽  
Variational Symmetries

We undertake a detailed analysis of the symmetry structures of the plane symmetric and the locally rotationally symmetric (LRS) Bianchi type I spacetimes in the [Formula: see text] gravity. In particular, we construct all the variational symmetries associated with its Lagrangian and, in some cases, construct the associated conservation laws using Noether’s theorem. Giving a comparison between isometries and variational symmetries, we give symmetry structures of some well-known spacetimes.

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