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The dynamics of the Universe is analyzed using an exponential function for the dark energy equation of state, known as Gong-Zhang parameterization. The phase space of the free parameters presented in the model is constrained using Cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-19 Mónica N. Castillo-Santos , A. Hernández-Almada , Miguel A. García-Aspeitia , Juan Magaña

In this paper, we study the new Tsallis agegraghic dark energy model in the context of fractal cosmology. The different cosmic implications such as statefinder diagnosis, cosmological plane and squared of sound speed in both interacting and…

General Relativity and Quantum Cosmology · Physics 2024-01-17 M. Abdollahi Zadeh

We review the Equation of State (EoS) approach to dark sector perturbations and apply it to $f(\mathcal{R})$ gravity models of dark energy. We show that the EoS approach is numerically stable and use it to set observational constraints on…

Cosmology and Nongalactic Astrophysics · Physics 2018-06-18 Richard A. Battye , Boris Bolliet , Francesco Pace

There is currently no consistent approach to modelling galaxy bias evolution in cosmological inference. This lack of a common standard makes the rigorous comparison or combination of probes difficult. We show that the choice of biasing…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-16 L. Clerkin , D. Kirk , O. Lahav , F. B. Abdalla , E. Gaztanaga

The discovery of apparent cosmological acceleration has spawned a huge number of dark energy and modified gravity theories. The f(R) models of gravity are obtained when one replaces the Ricci scalar in the Einstein-Hilbert action by an…

General Relativity and Quantum Cosmology · Physics 2016-02-08 Boris Bolliet , Richard A. Battye , Jonathan A. Pearson

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

We perform a Bayesian inference of the dense-matter equation of state (EOS) within a unified framework that incorporates hadronic matter, quark matter, and a smooth hadron-to-quark crossover. The EOS is constrained using physical…

Nuclear Theory · Physics 2026-05-11 Xavier Grundler , Bao-An Li

Understanding the evolution of dark energy poses a significant challenge in modern cosmology, as it is responsible for the universe's accelerated expansion. In this study, we focus on a specific $f(T)$ cosmological model and analyze its…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-14 A. Zhadyranova , M. Koussour , S. Bekkhozhayev , V. Zhumabekova , J. Rayimbaev

We generalize the $\Lambda$CDM model by introducing a unified EOS to describe the Universe contents modeled as dark viscous fluid, motivated by the fact that a single constant equation of state (EOS) $p=-p_0$ ($p_0>0$) reproduces the…

Astrophysics · Physics 2008-11-26 Jie Ren , Xin-He Meng

We apply a new non-parametric Bayesian method for reconstructing the evolution history of the equation-of-state $w$ of dark energy, based on applying a correlated prior for $w(z)$, to a collection of cosmological data. We combine the latest…

Cosmology and Nongalactic Astrophysics · Physics 2013-03-20 Gong-Bo Zhao , Robert G. Crittenden , Levon Pogosian , Xinmin Zhang

We examine the observational viability and physical implications of the Gong-Zhang (GZ) dark--energy equation-of-state parametrizations using exclusively late-time cosmological probes. Two one-dimensional parametrization models, GZ-Type~I…

General Relativity and Quantum Cosmology · Physics 2026-03-06 Anirban Chatterjee , Yungui Gong

Over the past decade, an abundance of information from neutron-star observations, nuclear experiments and theory has transformed our efforts to elucidate the properties of dense matter. However, at high densities relevant to the cores of…

High Energy Astrophysical Phenomena · Physics 2025-10-10 Sunny Ng , Isaac Legred , Lami Suleiman , Philippe Landry , Lyla Traylor , Jocelyn Read

The equation of state (EoS) of hot and dense matter is a fundamental input to describe static and dynamical properties of neutron stars, core-collapse supernovae and binary compact-star mergers. We review the current status of the EoS for…

Nuclear Theory · Physics 2019-03-06 G. Fiorella Burgio , Anthea F. Fantina

The fundamental nature and origin of dark energy are one of the premier mysteries of theoretical physics. In General Relativity Theory, the cosmological constant $\Lambda$ is the simplest explanation for dark energy. On the other hand, the…

General Relativity and Quantum Cosmology · Physics 2022-05-27 Raja Solanki , Avik De , Sanjay Mandal , P. K. Sahoo

So far large and different data sets revealed the accelerated expansion rate of the Universe, which is usually explained in terms of dark energy. The nature of dark energy is not yet known, and several models have been introduced: a non…

Cosmology and Nongalactic Astrophysics · Physics 2021-06-16 M. Demianski , E. Piedipalumbo , D. Sawant , L. Amati

Recent measurements of Baryon Acoustic Oscillations (BAO) and distance moduli from Type Ia supernovae suggest a preference for Dynamical Dark Energy (DDE) scenarios characterized by a time-varying equation of state (EoS). This focused…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-11 William Giarè , Tariq Mahassen , Eleonora Di Valentino , Supriya Pan

The attempt to describe the recent accelerated expansion of the Universe includes different propositions for dark energy models and modified gravity theories. Establish their features in order to discriminate and even rule out part of these…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-01 M. Penna-Lima , S. D. P. Vitenti , M. E. S. Alves , J. C. N. de Araujo , F. C. Carvalho

We combine complementary datasets from Cosmic Microwave Background (CMB) anisotropy measurements, high redshift supernovae (SN-Ia) observations and data from local cluster abundances and galaxy clustering (LSS) to constrain the dark energy…

Astrophysics · Physics 2009-11-07 Rachel Bean , Alessandro Melchiorri

We use a variant of principal component analysis to investigate the possible temporal evolution of the dark energy equation of state, w(z). We constrain w(z) in multiple redshift bins, utilizing the most recent data from Type Ia supernovae,…

Cosmology and Nongalactic Astrophysics · Physics 2010-01-07 Paolo Serra , Asantha Cooray , Daniel E. Holz , Alessandro Melchiorri , Stefania Pandolfi , Devdeep Sarkar

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