scholarly journals Ricci and Matter Collineations of Locally Rotationally Symmetric Space-Times

2004 ◽  
Vol 36 (1) ◽  
pp. 47-69 ◽  
Author(s):  
Michael Tsamparlis ◽  
Pantelis S. Apostolopoulos
Keyword(s):  
Symmetric Space ◽  
Matter Collineations ◽  
Locally Rotationally Symmetric ◽  
Rotationally Symmetric

scholarly journals SYMMETRIES OF LOCALLY ROTATIONALLY SYMMETRIC MODELS

2005 ◽  
Vol 14 (10) ◽  
pp. 1675-1684 ◽  
Author(s):  
M. SHARIF
Keyword(s):  
Symmetric Space ◽  
Energy Momentum Tensor ◽  
Momentum Tensor ◽  
Interesting Case ◽  
Degenerate Case ◽  
Infinite Dimensional ◽  
Constraint Equations ◽  
Matter Collineations ◽  
Locally Rotationally Symmetric ◽  
Rotationally Symmetric

Matter collineations of locally rotationally symmetric space–times are considered. These are investigated when the energy–momentum tensor is degenerate. We know that the degenerate case provides infinite dimensional matter collineations in most of the cases. However, an interesting case arises where we obtain proper matter collineations. We also solve the constraint equations for a particular case to obtain some cosmological models.

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.

Sign in / Sign up

Export Citation Format

Share Document