| 1. |
- Coley, Alan A., et al.
(author)
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Spherically symmetric Einstein-aether perfect fluid models
- 2015
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In: Journal of Cosmology and Astroparticle Physics. - : Institute of Physics (IOP). - 1475-7516. ; :12
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Journal article (peer-reviewed)abstract
- We investigate spherically symmetric cosmological models in Einstein-act her theory with a tilted (non-comoving) perfect fluid source. We use a 1+3 frame formalism and adopt the comoving aether gauge to derive the evolution equations, which form a well-posed system of first order partial differential equations in two variables. We then introduce normalized variables. The formalism is particularly well-suited for numerical computations and the study of the qualitative properties of the models, which are also solutions of Horava gravity. We study the local stability of the equilibrium points of the resulting dynamical system corresponding to physically realistic in homogeneous cosmological models and astrophysical objects with values for the parameters which are consistent. with current constraints. In particular, we consider dust models in (beta-) normalized variables and derive a reduced (closed) evolution system and we obtain the general evolution equations for the spatially homogeneous Kantowski-Sachs models using, appropriate bounded normalized variables. We then analyse these models, with special emphasis on the future asymptotic behaviour for different values of the parameters. Finally, we investigate static models for a mixture of a (necessarily non-tilted) perfect fluid with a barotropic equations of state and a scalar field.
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| 2. |
- Alhulaimi, Bassemah, et al.
(author)
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Anisotropic Einstein-aether cosmological models
- 2013
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In: Journal of Mathematical Physics. - Melville, USA : American Institute of Physics (AIP). - 0022-2488 .- 1089-7658. ; 54:4
-
Journal article (peer-reviewed)abstract
- We investigate a class of spatially anisotropic cosmological models in Einstein-aether theory with a scalar field in which the self-interaction potential depends on the timelike aether vector field through the expansion and shear scalars. We derive the evolution equations in terms of expansion-normalized variables, which reduce to a dynamical system. We study the local stability of the equilibrium points of the dynamical system corresponding to physically realistic solutions, and find that there are always ranges of values of the parameters of the models for which there exists an inflationary attractor. © 2013 AIP Publishing LLC.
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| 3. |
- Sandin, Patrik, et al.
(author)
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Stability of Einstein-aether cosmological models
- 2013
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In: Physical Review D. - USA : American Physical Society. - 1550-7998 .- 1550-2368. ; 87:4
-
Journal article (peer-reviewed)abstract
- We use a dynamical systems analysis to investigate the future behavior of Einstein-Aether cosmological models with a scalar field coupling to the expansion of the aether and a noninteracting perfect fluid. The stability of the equilibrium solutions are analyzed, and the results are compared with the standard inflationary cosmological solutions and previously studied cosmological Einstein-aether models. © 2013 American Physical Society.
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