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We discuss an evolutionary dark energy model, based on the presence of non-equilibrium effects on the dark energy constituents, which are described via a bulk viscosity contribution. We implement the proposed dynamics by the analysis of the…

General Relativity and Quantum Cosmology · Physics 2025-02-12 Giovanni Montani , Nakia Carlevaro , Maria G. Dainotti

Using the 37-point cosmic-chronometer subset of observational Hubble parameter (OHD) data, we develop a Bayesian Gaussian-process framework to reconstruct the normalized dark-energy density \(f(z)\) and equation of state \(w(z)\), focusing…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-14 Jia-yan Jiang , Wei Hong , Tong-jie Zhang

Observations restrict the parameter space of Holographic Dark Energy (HDE) so that a turning point in the Hubble parameter $H(z)$ is inevitable. Concretely, cosmic microwave background (CMB), baryon acoustic oscillations (BAO) and Type Ia…

General Relativity and Quantum Cosmology · Physics 2021-08-11 Eoin Ó Colgáin , M. M. Sheikh-Jabbari

We refine and extend a programme initiated by one of the current authors [Science 276 (1997) 88; Phys. Rev. D56 (1997) 7578] advocating the use of the classical energy conditions of general relativity in a cosmological setting to place very…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Celine Cattoen , Matt Visser

We present logistic dark energy model (LDEM), where the dark energy density follows a logistic function for the scale factor. The equation of state parameter of dark energy ($w_D$) transitioned from $-1$ in the distant past to its current…

Cosmology and Nongalactic Astrophysics · Physics 2024-06-27 Sarath Nelleri , Gopi Krishna , Navaneeth Poonthottathil

The motivation of the present work is to reconstruct a dark energy model through the {\it dimensionless dark energy function} $X(z)$, which is the dark energy density in units of its present value. In this paper, we have shown that a scalar…

General Relativity and Quantum Cosmology · Physics 2017-02-01 Abdulla Al Mamon , Kazuharu Bamba , Sudipta Das

In the present work, we investigate the power-law entropy corrected holographic dark energy (PLECHDE) model with Hubble horizon cutoff. We use 46 observational Hubble data points in the redshift range $0 \leq z \leq 2.36$ to determine the…

General Relativity and Quantum Cosmology · Physics 2022-07-05 Vinod Kumar Bhardwaj , Priyanka Garg , Anirudh Pradhan , Syamala Krishnannair

In this paper, we use three different kinds of observational data, including 130 strong gravitational lensing (SGL) systems, type Ia supernovae (SNeIa: Pantheon and Union2.1) and 31 Hubble parameter data points ($H(z)$) from cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2022-11-16 Jing-Wang Diao , Yu Pan , Wenxiao Xu

We introduce a new parametrization for the dark energy, led by the same idea to the linear expansion of the equation of state in scale factor $a$ and in redshift $z$, which diverges neither in the past nor future and contains the same…

Cosmology and Nongalactic Astrophysics · Physics 2015-07-01 Ozgur Akarsu , Tekin Dereli , J. Alberto Vazquez

We consider holographic cosmological models of dark energy in which the infrared cutoff is set by the Hubble's radius. We show that any interacting dark energy model, regardless of its detailed form, can be recast as a non interacting model…

Cosmology and Nongalactic Astrophysics · Physics 2013-01-16 Ivan Duran , Luca Parisi

This study investigates the cosmological implications of $f(R,\Sigma,T)$ gravity by reconstructing the Hubble parameter from a logarithmic parameterization of the $O_m(z)$ diagnostic. Our approach offers a model-independent way to probe the…

General Relativity and Quantum Cosmology · Physics 2026-05-12 N. Myrzakulov , Anirudh Pradhan , Anil Kumar Yadav , S. H. Shekh

We consider a model-independent approach to constrain the equivalence redshift, $z_{eq}$, at which dark energy and the total matter (cold dark matter and baryonic) equate their magnitudes. To this aim, in the context of a homogeneous and…

Cosmology and Nongalactic Astrophysics · Physics 2023-08-31 Anna Chiara Alfano , Carlo Cafaro , Salvatore Capozziello , Orlando Luongo

In the studies on pre-recombination early dark energy (EDE), the evolution of Universe after recombination is usually regarded as ${\Lambda}CDM$-like, which corresponds that the equation of state of dark energy responsible for current…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-01 Hao Wang , Yun-Song Piao

We investigate the generalized Chevallier-Polarski-Linder (CPL) parametrization, which contains the pivoting redshift $z_p$ as an extra free parameter. We use various data combinations from cosmic microwave background (CMB), baryon acoustic…

Cosmology and Nongalactic Astrophysics · Physics 2018-11-19 Weiqiang Yang , Supriya Pan , Eleonora Di Valentino , Emmanuel N. Saridakis

We obtain the reduced CMB data $\{l_A, R, z_*\}$ from WMAP9, WMAP9+BICEP2, Planck+WP and Planck+WP+BICEP2 for the $\Lambda$CDM and $w$CDM models with or without spatial curvature. We then use these reduced CMB data in combination with…

Cosmology and Nongalactic Astrophysics · Physics 2015-07-06 Rong-Gen Cai , Zong-Kuan Guo , Bo Tang

The current paper is addressing the possibility of the Dark Energy scalar field potential reconstruction from the SNe Ia data and the problems arising during the process. We describe the method and test its limits, stability of the…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-24 Sergey Pavluchenko , Luca Amendola , Arpine Piloyan

The equation of state (EoS) of dark energy plays an important role in the evolution of the universe and arouses great interests in recent years. With the progress on observational technique, precise constraint on the EoS of dark energy…

General Relativity and Quantum Cosmology · Physics 2019-08-19 Hai-Nan Lin , Xin Li , Li Tang

We place tight constraints on the redshift-averaged, effective value of the equation of state of dark energy, w, using only the absolute ages of Galactic stars and the observed position of the first peak in the angular power spectrum of the…

Astrophysics · Physics 2011-07-18 Raul Jimenez , Licia Verde , Tommaso Treu , Daniel Stern

In this paper, we have proposed a generalized parametrization for the deceleration parameter $q$ in order to study the evolutionary history of the universe. We have shown that the proposed model can reproduce three well known…

General Relativity and Quantum Cosmology · Physics 2018-04-25 Abdulla Al Mamon

We report the constraints on the dark energy equation-of-state w(z) using the latest 'Constitution' SNe sample combined with the WMAP5 and SDSS data. Based on the localized principal component analysis and the model selection criteria, we…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-30 Gong-Bo Zhao , Xinmin Zhang
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