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Related papers: A general parametric model for the dynamic dark en…

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In the symmetric teleparallel gravity framework, we study the cosmic dynamics of the universe with dark energy equation of state (EoS) parameter having non-linear forms. The non-metricity scalar induced by the dark energy EoS parameter…

General Relativity and Quantum Cosmology · Physics 2025-07-10 Romanshu Garg , G. P. Singh , Ashutosh Singh

Cosmological models with different types of Dark Energy are becoming viable alternatives for standard models with the cosmological constant. Yet, such models are more difficult to analyze and to simulate. We present analytical…

Astrophysics · Physics 2009-11-07 R. Mainini , A. V. Maccio' , S. A. Bonometto , A. Klypin

We investigate a dynamical reconstruction of the dark energy equation of state parameter by assuming that it satisfies a law of motion described by an autonomous second-order differential equation, with the limit of the cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-25 Andronikos Paliathanasis

We propose a new dark energy (DE) model from four parameter generalized entropy function of apparent horizon in a spatially flat universe. Such kind of generalized entropy is able to generalize all the known entropies proposed so far, for…

General Relativity and Quantum Cosmology · Physics 2025-07-22 Priyanka Adhikary , Sudipta Das , Sergei D. Odintsov , Tanmoy Paul

The nature of dark matter remains one of the most fundamental and unresolved questions in modern cosmology. In most cosmological models, dark matter is typically modeled as pressureless dust with an equation of state (EoS) parameter $w_{\rm…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-22 Tian-Nuo Li , Yi-Min Zhang , Yan-Hong Yao , Peng-Ju Wu , Jing-Fei Zhang , Xin Zhang

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

A comparative study of various parametrizations of the dark energy equation of state is made. Astrophysical constraints from LSS, CMB and BBN are laid down to test the physical viability and cosmological compatibility of these…

Astrophysics · Physics 2008-11-26 Vinod B. Johri , P. K. Rath

We study the cosmological properties of a dynamical of dark energy (DE) component determined by a Steep Equation of State (SEoS) $w(z)=w_0+w_i\frac{(z/z_T)^q}{1+(z/z_T)^q}$. The SEoS has a transition at $z_T$ between two pivotal values…

Cosmology and Nongalactic Astrophysics · Physics 2019-09-27 Mariana Jaber , Erick Almaraz , Axel de la Macorra

In this paper, we present a comprehensive cosmological analysis within the framework of $f(R, \Sigma, T)$ gravity, a modified theory that incorporates nonlinear matter-geometry coupling via the inclusion of both the trace of the…

General Relativity and Quantum Cosmology · Physics 2025-11-24 S. H. Shekh , N. Myrzakulov , Anil Kumar Yadav , Anirudh Pradhan

In the past few years, $f(Q)$ theories have drawn a lot of research attention in replacing Einstein's theory of gravity successfully. The current study examines the novel cosmological possibilities emerging from two specific classes of…

General Relativity and Quantum Cosmology · Physics 2023-05-31 M. Koussour , Avik De

The paper brings a novel approach to unification of dark matter and dark energy in terms of a cosmic fluid. A model is introduced in which the cosmic fluid speed of sound squared is defined as a function of its equation of state (EoS)…

General Relativity and Quantum Cosmology · Physics 2019-08-06 Dalibor Perkovic , Hrvoje Stefancic

The current paper provides a comprehensive examination of a dark energy cosmological model in the classical regime, in which a generic scalar field is regarded as a dark energy source. Einstein's field equations are solved in model…

General Relativity and Quantum Cosmology · Physics 2022-09-07 Ritika Nagpal , Shibesh Kumar Jas Pacif , Abhishek Parida

In this study, we investigate the late-time accelerated expansion of the universe within the framework of non-minimally coupled $f(Q,L_m)$ gravity, where $Q$ is the non-metricity scalar and $L_m$ is the matter Lagrangian. We derive modified…

General Relativity and Quantum Cosmology · Physics 2025-07-08 Yash B. Ingole , K. V. Somwanshi , S. R. Bhoyar , S. N. Bayaskar

Recent observations of DESI hint that dark matter (DM) may not be cold but have a non-zero equation of state (EoS) parameter, and that dark energy (DE) may not be a cosmological constant. In this work, we explore the possibility of a…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-03 Tian-Nuo Li , Peng-Ju Wu , Guo-Hong Du , Yan-Hong Yao , Jing-Fei Zhang , Xin Zhang

We study the cosmic expansion history by reconstructing the deceleration parameter $q(z)$ from the SDSS-II type Ia supernova sample (SNIa) with two different light curve fits (MLCS2k2 and SALT-II), the baryon acoustic oscillation (BAO)…

General Relativity and Quantum Cosmology · Physics 2011-05-10 Zhengxiang Li , Puxun Wu , Hongwei Yu

In this paper we present a generic form of the cosmological Equation of State derived from the formalism of Statistical Mechanics, assuming that a cosmic acceleration scenario can be interpreted as a system of quasi-particles. By…

General Relativity and Quantum Cosmology · Physics 2020-12-14 Elías Castellanos , Celia Escamilla-Rivera

We examine the validity of the $\Lambda$CDM model, and probe for the dynamics of dark energy using latest astronomical observations. Using the $Om(z)$ diagnosis, we find that different kinds of observational data are in tension within the…

Cosmology and Nongalactic Astrophysics · Physics 2017-06-14 Yuecheng Zhang , Hanyu Zhang , Dandan Wang , Yanghan Qi , Yuting Wang , Gong-Bo Zhao

In this paper, we focus on the parametrization of the effective equation of state (EoS) parameter within the framework of $f(Q)$ symmetric teleparallel gravity. Here, the gravitational action is represented by an arbitrary function of the…

General Relativity and Quantum Cosmology · Physics 2023-07-04 A. Mussatayeva , N. Myrzakulov , M. Koussour

Dark energy (DE) models with many free parameters are often considered excessive, as constraining all parameters poses a significant challenge. While such models offer greater flexibility to probe the DE sector in more detail. With the…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-25 Hanyu Cheng , Supriya Pan , Eleonora Di Valentino

Late-time cosmic acceleration is one of the most interesting unsolved puzzles in modern cosmology. The explanation most accepted nowadays, dark energy, raises questions about its own nature, e.g. what exactly is dark energy, and…

Cosmology and Nongalactic Astrophysics · Physics 2019-04-26 Williams J. M. Ribeiro
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