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The dynamics of expansion and large scale structure formation in the multicomponent Universe with dark energy modeled by the minimally coupled scalar field with generalized linear barotropic equation of state (EoS) are analyzed. It is shown…

Cosmology and Nongalactic Astrophysics · Physics 2010-12-09 B. Novosyadlyj , O. Sergijenko , S. Apunevych , V. Pelykh

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 propose a logarithmic parametrization form of energy density for the scalar field dark energy in the framework of the standard theory of gravity, which supports the necessary transition from the decelerated to the accelerated behavior of…

General Relativity and Quantum Cosmology · Physics 2023-07-31 Dan Wang , M. Koussour , Adnan Malik , N. Myrzakulov , G. Mustafa

We consider how well the dark energy equation of state $w$ as a function of red shift $z$ will be measured using current and anticipated experiments. We use a procedure which takes fair account of the uncertainties in the functional…

Astrophysics · Physics 2011-02-01 Amol Upadhye , Mustapha Ishak , Paul J. Steinhardt

We reconstruct the effective Equation of State (EoS) within the framework of General Relativity (GR) theory in a homogeneous and isotropic FLRW Universe, which is assumed to be composed of matter and Dark Energy (DE). Our analysis employs a…

General Relativity and Quantum Cosmology · Physics 2023-09-29 N. Myrzakulov , M. Koussour , Alnadhief H. A. Alfedeel , E. I. Hassan

We study the degeneracies between dark energy dynamics, dark matter and curvature using a non-parametric and non-perturbative approach. This allows us to examine the knock-on bias induced in the reconstructed dark energy equation of state,…

Astrophysics · Physics 2008-08-05 Renée Hlozek , Marina Cortês , Chris Clarkson , Bruce Bassett

We constrain two dynamical dark energy models that are parametrized by the logarithm form of $w(z)=w_{0}+w_{1}\left(\frac{\ln (2+z)}{1+z}-\ln 2\right)$ and the oscillating form of…

General Relativity and Quantum Cosmology · Physics 2023-11-28 Tian-Ying Yao , Rui-Yun Guo , Xin-Yue Zhao

Using late-Universe observations, we demonstrate that freeing dark energy and dark matter equations of state (EoS) dramatically alters the inferred strength and direction of their interactions. When dark sector EoS are fixed to…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-25 Peng-Ju Wu , Ming Zhang , Shang-Jie Jin

We investigate the dark energy phenomenology in an extended parameter space where we allow the curvature density of our universe as a free-to-vary parameter. The inclusion of the curvature density parameter is motivated from the recently…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-29 Mehdi Rezaei , Supriya Pan , Weiqiang Yang , David F. Mota

For exploring the physics behind the accelerating universe a crucial question is how much we can learn about the dynamics through next generation cosmological experiments. For example, in defining the dark energy behavior through an…

Astrophysics · Physics 2011-05-12 Eric V. Linder , Dragan Huterer

The behavior of the dark energy equation of state (EOS) is crucial in distinguishing different cosmological models. With a model independent approach, we constrain the possible evolution of the dark energy EOS. Gamma-ray bursts (GRBs) of…

Astrophysics · Physics 2008-12-20 Shi Qi , Fa-Yin Wang , Tan Lu

The cosmological model with an interaction between dynamical quintessence dark energy and cold dark matter is considered. Evolution of a dark energy equation of state parameter is defined by a dark energy adiabatic sound speed and a dark…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-08 Roman Neomenko

We investigate cosmological models in which dynamical dark energy consists of a scalar field whose present-day value is controlled by a coupling to the neutrino sector. The behaviour of the scalar field depends on three functions: a kinetic…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-21 Finlay Noble Chamings , Anastasios Avgoustidis , Edmund J. Copeland , Anne M. Green , Baojiu Li

We assess the viability of successful reconstruction of the evolution of the dark energy equation of state using varying fundamental couplings, such as the fine structure constant or the proton-to-electron mass ratio. We show that the same…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 P. P. Avelino , L. Losano , R. Menezes , J. C. R. E. Oliveira

We investigate a kind of holographic dark energy model with the future event horizon the IR cutoff and the equation of state -1. In this model, the constraint on the equation of state automatically specifies an interaction between matter…

Astrophysics · Physics 2007-05-23 Hui Li , Zong-kuan Guo , Yuan-zhong Zhang

Dark Energy not only has background effects through its equation of state $w_{DE}$, but also it can cluster through its sound speed $c^2_{sDE}$, subject to certain conditions. As is well-known, for dynamical dark energy models, dark energy…

Cosmology and Nongalactic Astrophysics · Physics 2019-07-26 Archita Bhattacharyya , Supratik Pal

Recent analysis of the DESI Collaboration challenges the $\Lambda$-Cold Dark Matter ($\Lambda$CDM) model, suggesting evidence for a dynamic dark energy. These results are obtained in the context of generic parameterizations of the dark…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-21 Rayff de Souza , Gabriel Rodrigues , Jailson Alcaniz

We present a Dark Energy (DE) model with a sound derivation as a natural extension of the Standard Model of particle physics with no free parameters and an excellent fit with current cosmological data improving by 21% the $\Lambda$CDM fit…

Cosmology and Nongalactic Astrophysics · Physics 2018-10-24 A. de la Macorra , E. Almaraz

We investigate the cosmological implications of a generalized total equation of state (EoS) model by constraining its parameters using observational datasets to effectively characterize the universe's expansion history and its dynamic…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-14 M. Koussour , S. Bekov , A. Syzdykova , S. Muminov , I. Ibragimov , J. Rayimbaev

The reconstruction of a (non)canonical scalar field Lagrangian from the dark energy Equation of State (EoS) parameter is studied, where it is shown that any EoS parametrization can be well reconstructed in terms of scalar fields. Several…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 Iker Leanizbarrutia , Diego Sáez-Gómez