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We study the accelerating expansion and the induced dark energy of the $5D$ Ricci-flat universe which is characterized by having a big bounce as opposed to a big bang. We show that the arbitrary function $\mu(t)$ contained in the $5D$…

Astrophysics · Physics 2009-11-13 Lixin Xu , Hongya Liu , Baorong Chang

A five-dimensional Ricci-flat cosmological solution is studied by assuming that the induced 4D matter contains two components: the usual fluid for dark matter as well as baryons and a scalar field with an exponential potential for dark…

Astrophysics · Physics 2009-11-10 Baorong Chang , Hongya Liu , Huanying Liu , Lixin Xu

The dark sector of the Universe need not be completely separable into distinct dark matter and dark energy components. We consider a model of early dark energy in which the dark energy mimics a dark matter component in both evolution and…

Cosmology and Nongalactic Astrophysics · Physics 2014-09-05 Jannis Bielefeld , Robert R. Caldwell , Eric V. Linder

Following the idea of the induced matter theory, for a non-vacuum five-dimensional version of general relativity, we propose a model in which the induced terms emerging from the extra dimension in our four-dimensional space-time, supposed…

General Relativity and Quantum Cosmology · Physics 2018-07-27 Amir F. Bahrehbakhsh

Dark Energy is some of the weirdest and most mysterious stuff in the universe that tends to increase the rate of expansion of the universe. Two commonly known forms of dark energy are the cosmological constant, a constant energy density…

General Relativity and Quantum Cosmology · Physics 2010-04-28 Ishwaree P. Neupane , Holly Trowland

We study cosmological perturbations in a model of unified dark matter and dark energy with a sharp transition in the late-time universe. The dark sector is described by a dark fluid which evolves from an early stage at redshifts $z > z_C$…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-05 Rodrigo R. Cuzinatto , Léo G. Medeiros , Eduardo M. de Morais , Robert H. Brandenberger

We consider a five-dimensional Ricci flat Bouncing cosmology and assume that the four-dimensional universe is permeated smoothly by three minimally coupled matter components: CDM+baryons $\rho_{m}$, radiation $\rho_{r}$ and dark energy…

Astrophysics · Physics 2009-11-10 Lixin Xu , Hongya Liu

We propose a new dark energy model for solving the cosmological fine-tuning and coincidence problems. A default assumption is that the fine-tuning problem disappears if we do not interpret dark energy as vacuum energy. The key idea to…

Cosmology and Nongalactic Astrophysics · Physics 2020-03-27 S. X. Tián

We investigate Dark Energy by associating it with vacuum energy or Cosmological constant ${\Lambda}$ which is taken to be dynamic in nature. Our approach is phenomenological and falls within the domain of variable-$\Lambda$ Cosmology.…

Cosmology and Nongalactic Astrophysics · Physics 2022-02-08 Arkajit Aich

We study a phenomenological dark energy model which is rooted in the Veneziano ghost of QCD. In this dark energy model, the energy density of dark energy is proportional to Hubble parameter and the proportional coefficient is of the order…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Rong-Gen Cai , Qiping Su , Zhong-Liang Tuo , Hong-Bo Zhang

We investigate the possibility of a dark energy component that is scaling with epochs. A phenomenological model is introduced whose energy density depends on the redshift in such a way that a smooth transition among the three dominant…

Astrophysics · Physics 2009-11-10 Salvatore Capozziello , Alessandro Melchiorri , Alice Schirone

A phenomenological model of dark energy that tracks the baryonic and cold dark matter at early times but resembles a cosmological constant at late times is explored. In the transition between these two regimes, the dark energy density drops…

Cosmology and Nongalactic Astrophysics · Physics 2013-11-13 Jannis Bielefeld , W. L. Kimmy Wu , Robert R. Caldwell , Olivier Dore

A dynamical model for the dark energy is presented in which the ``quintessence'' field is the axion, $a_Z$, of a spontaneously broken global $U(1)_{A}^{(Z)}$ symmetry whose potential is induced by the instantons of a new gauge group…

High Energy Physics - Phenomenology · Physics 2010-11-05 P. Q. Hung

We use a parameterized equation of state (EOS) of dark energy to a 5D Ricci-flat cosmological solution and suppose the universe contains two major components: dark matter and dark energy. Using the recent observational datasets: the latest…

Astrophysics · Physics 2009-06-23 Chengwu Zhang , Lixin Xu , Yongli Ping , Hongya Liu

In this letter, it is obtained using dual role of the Ricci scalar (physical as well as geometrical role of the Ricci scalar curvature) in a natural way without any input in the theory for it. In contrast to other models, where an idea for…

Astrophysics · Physics 2007-05-23 S. K. Srivastava

Bouncing models have been proposed by many authors as a completion, or even as an alternative to inflation for the description of the very early and dense Universe. However, most bouncing models contain a contracting phase from a very large…

Cosmology and Nongalactic Astrophysics · Physics 2012-01-31 Rodrigo Maier , Stella Pereira , Nelson Pinto-Neto , Beatriz B. Siffert

The coupling between the dark components provides a new approach to mitigate the coincidence problem of cosmological standard model. In this paper, dark energy is treated as a fluid with a constant equation of state, whose coupling with…

Cosmology and Nongalactic Astrophysics · Physics 2014-08-18 Weiqiang Yang , Lixin Xu

Following the approach of the induced-matter theory, we investigate the cosmological implications of a five-dimensional Brans-Dicke theory, and propose to explain the acceleration of the universe. After inducing in a four-dimensional…

General Relativity and Quantum Cosmology · Physics 2013-07-10 Amir F. Bahrehbakhsh , Mehrdad Farhoudi , Hajar Vakili

Anisotropic dark energy model with dynamic pressure anisotropies along different spatial directions is constructed at the backdrop of a spatially homogeneous diagonal Bianchi type $V$ $(BV)$ space-time in the framework of General…

General Physics · Physics 2017-05-10 B. Mishra , S. K. Tripathy

We consider a class of five-dimensional cosmological solutions which contains two arbitrary function $\mu(t)$ and $\nu(t)$. We found that the arbitrary function $\mu(t)$ contained in the solutions can be rewritten in terms of the redshift…

Astrophysics · Physics 2009-11-13 Lixin Xu , Hongya Liu , Chengwu Zhang
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