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A large number of recent observational data strongly suggest that we live in a flat, accelerating Universe composed of $\sim$ 1/3 of matter (baryonic + dark) and $\sim$ 2/3 of an exotic component with large negative pressure, usually named…

Astrophysics · Physics 2015-06-24 J. A. S. Lima

Accelerating cosmological models are constructed in a modified gravity theory dubbed as $f(R,T)$ gravity at the backdrop of an anisotropic Bianchi type-III universe. $f(R,T)$ is a function of the Ricci scalar $R$ and the trace $T$ of the…

General Relativity and Quantum Cosmology · Physics 2017-06-21 S K Sahu , S K Tripathy , P K Sahoo , A Nath

In this work we consider a dark matter candidate described by an ultralight vector field, whose mass is in principle in the range $H_{\rm{eq}}\sim 10^{-28}\rm{eV}\ll m< \rm{eV}$. The homogeneous background vector field is assumed to point…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-22 Tomás Ferreira Chase , Matías Leizerovich , Diana López Nacir , Susana Landau

We study a dark energy model with non-zero anisotropic stress, either linked to the dark energy density or to the dark matter density. We compute approximate solutions that allow to characterise the behaviour of the dark energy model and to…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-18 Wilmar Cardona , Lukas Hollenstein , Martin Kunz

Dark Energy models are here investigated and studied in the framework of the Chern-Simons modified gravity model. We bring into focus the Holographic Dark Energy (HDE) model with Granda-Oliveros cut-off, the Modified Holographic Ricci Dark…

General Relativity and Quantum Cosmology · Physics 2015-02-05 Antonio Pasqua , Roldao da Rocha , Surajit Chattopadhyay

We consider a dynamical model for dark energy based on an ultralight mass scalar field with very large-scale inhomogeneities. This model may cause observable impacts on the anisotropic properties of the cosmic microwave background (CMB)…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-11 Yue Nan , Kazuhiro Yamamoto

In the present work we have searched the existence of the late time acceleration of the universe with string fluid as source of matter in Bianchi V space-time. To get the deterministic solution, we choose the scale factor as increasing…

General Physics · Physics 2015-06-04 Anil Kumar Yadav

We characterize a class of simple FRW models filled by both dark energy and dark matter in notion of a single potential function of the scale factor $a(t)$; $t$ is the cosmological time. It is representing potential of fictitious particle -…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Marek Szydlowski , Aleksandra Kurek

In this paper we present the noncommutative Bianchi Class A cosmological models coupled to barotropic perfect fluid. The commutative and noncommutative quantum solution to the Wheeler-DeWitt equation for any factor ordering, to the…

General Relativity and Quantum Cosmology · Physics 2008-11-26 M. Aguero , J. A. Aguilar S. , C. Ortiz , M. Sabido , J. Socorro

In this paper, we study the late time cosmology of a non-canonical scalar field ($k$-essence) coupled to a vector field in a Bianchi-I background. Specifically, we study three cases: canonical scalar field (quintessence) with exponential…

General Relativity and Quantum Cosmology · Physics 2021-09-02 J. Bayron Orjuela-Quintana , César A. Valenzuela-Toledo

We propose a new fluid model of dark energy for $-1 \leq \omega_{\text{eff}} \leq 0$ as an alternative to the generalized Chaplygin gas models. The energy density of dark energy fluid is severely suppressed during barotropic matter dominant…

Cosmology and Nongalactic Astrophysics · Physics 2010-11-23 Hoavo Hova , Huanxiong Yang

We generalize the predictions for the CMB anisotropy patterns arising in Bianchi type VIIh universes to include a dark energy component. We consider these models in light of the result of Jaffe et al. (2005a,b) in which a correlation was…

Astrophysics · Physics 2009-11-13 T. R. Jaffe , S. Hervik , A. J. Banday , K. M. Gorski

We investigate in this paper the cosmological evolution of a dark energy model with two scalar fields where one of the scalar has canonical kinetic energy and another scalar has negative kinetic energy term. For such a system with…

Astrophysics · Physics 2007-05-23 Zong-Kuan Guo , Yun-Song Piao , Xinmin Zhang , Yuan-Zhong Zhang

We propose a dark energy model with a logarithmic cosmological fluid which can result in a very small current value of the dark energy density and avoid the coincidence problem without much fine-tuning. We construct a couple of dynamical…

General Relativity and Quantum Cosmology · Physics 2014-07-30 Seyen Kouwn , Phillial Oh

Bianchi type V matter filled universe with varying lambda in general relativity are investigated by using the law of variation for the generalized mean Hubble parameter. This yields the constant value of deceleration parameter and generates…

General Relativity and Quantum Cosmology · Physics 2013-01-15 Anil Kumar Yadav

In our study, we explored the properties of a spatially homogeneous and anisotropic Bianchi type V I0 Universe. Our investigation centered on integrating cosmic domain walls into the f(R, T) theory of gravitation, initially proposed by…

General Relativity and Quantum Cosmology · Physics 2024-03-05 V. R. Patil , J. L. Pawde , R. V. Mapari , S. K. Waghmare

We study the background cosmological dynamics with a three component source content: a radiation fluid, a barotropic fluid to mimic the matter sector and a single scalar field which can act as dark energy giving rise to the late-time…

Cosmology and Nongalactic Astrophysics · Physics 2016-05-09 Suprit Singh , Parminder Singh

We study the cosmological evolution of two coupled scalar fields with an arbitrary interaction term V_T(\phi,\vp) in the presence of a barotropic fluid, which can be matter or radiation. The force between the barotropic fluid and the scalar…

Astrophysics · Physics 2008-11-26 A. de la Macorra

The coincidence problems and other dynamical features of dark energy are studied in cosmological models with variable cosmological parameters and in models with the composite dark energy. It is found that many of the problems usually…

Astrophysics · Physics 2008-11-26 Javier Grande , Joan Sola , Hrvoje Stefancic

We study the anisotropic and homogeneous Bianchi type-V Universe with holographic dark energy (HDE) and interacting dark matter (DM). The solution for the field equations have been obtained for a certain form of the deceleration parameter.…

General Relativity and Quantum Cosmology · Physics 2025-07-29 Gunjan Varshney , Anirudh Pradhan , Nasr Ahmed , Vansh Mittal