scholarly journals Rotating and twisting locally rotationally symmetric spacetimes: A general solution

2017 ◽  
Vol 96 (6) ◽  
Author(s):  
Sayuri Singh ◽  
George F. R. Ellis ◽  
Rituparno Goswami ◽  
Sunil D. Maharaj
Keyword(s):  
General Solution ◽  
Locally Rotationally Symmetric ◽  
Symmetric Spacetimes ◽  
Rotationally Symmetric

k-essence cosmologies in Kantowski–Sachs and Bianchi space–times

2015 ◽  
Vol 93 (11) ◽  
pp. 1319-1323 ◽  
Author(s):  
T. Singh ◽  
R. Chaubey ◽  
Ashutosh Singh
Keyword(s):  
General Solution ◽  
Scalar Potential ◽  
Kinetic Function ◽  
Locally Rotationally Symmetric ◽  
Bianchi I ◽  
Initial Anisotropy ◽  
Rotationally Symmetric ◽  
Bianchi Iii ◽  
Function Models ◽  
Friedmann Robertson Walker

We investigate Kantowski–Sachs, locally rotationally symmetric Bianchi-I and Bianchi-III cosmology with k-essence and found a set of models that dissipate the initial anisotropy. We obtain the conditions leading to a regular bounce of the average geometry. We show that the linear k-field and polynomial kinetic function models evolve asymptotically to Friedmann–Robertson–Walker cosmologies. For linear k-essence we find the general solution in these cosmologies, when the k-field is driven by an inverse scalar potential.

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.

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