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Although $\Lambda$CDM model is very successful in many aspects, it has been seriously challenged. Recently, warm dark matter (WDM) remarkably rose as an alternative of cold dark matter (CDM). In the literature, many attempts have been made…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-28 Hao Wei , Zu-Cheng Chen , Jing Liu

The fact that Einstein's equations connect the space-time geometry to the total matter content of the cosmic substratum, but not to individual contributions of the matter species, can be translated into a degeneracy in the cosmological dark…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-26 Rodrigo von Marttens , Dinorah Barbosa , Jailson Alcaniz

There are various cosmological models with polytropic equation of state associated to dark energy. Polytropic EoS has important applications in astrophysics, therefore a study of it on cosmological framework continues to be interesting.…

General Physics · Physics 2015-10-28 Martiros Khurshudyan

We investigate the general relativistic dynamics of Robertson-Walker models with a non-linear equation of state (EoS), focusing on the quadratic case P = P_0 + \alpha \rho + \beta \rho^2. This may be taken to represent the Taylor expansion…

Astrophysics · Physics 2008-12-18 Kishore N. Ananda , Marco Bruni

There are many kinds of models which describe the dynamics of dark energy (DE). Among all we adopt an equation of state (EoS) which varies as a function of time. We adopt Markov Chain Monte Carlo method to constrain the five parameters of…

Cosmology and Nongalactic Astrophysics · Physics 2016-11-15 R. Ichimasa , E. P. B. A. Thushari , M. Hashimoto

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

One of the main aims in the next generation of precision cosmology experiments will be an accurate determination of the equation of state (EOS) for the dark energy (DE). If the latter is dynamical, the resulting barotropic index \omega…

Astrophysics · Physics 2009-11-13 Joan Sola , Hrvoje Stefancic

Exotic dark matter (EDM) refers to a dark matter species whose equation of state deviates from zero at late times. This behavior enables it to model a variety of non-standard late-time cosmologies, offering alternatives to various dark…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-24 Matteo Braglia , Xingang Chen , Abraham Loeb

In this latter author would like to consider interaction between a dark energy based on Generalized Uncertainty Principle (GUP) and a Dark Matter described by effective EoS: $P =…

General Physics · Physics 2013-03-12 Martiros Khurshudyan

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 study the late-time evolution of the Universe where dark energy (DE) is presented by a barotropic fluid on top of cold dark matter (CDM). We also take into account the radiation content of the Universe. Here by the late stage of the…

General Relativity and Quantum Cosmology · Physics 2015-07-24 Ozgur Akarsu , Mariam Bouhmadi-López , Maxim Brilenkov , Ruslan Brilenkov , Maxim Eingorn , Alexander Zhuk

We study a correspondence between $f(R)$ model of gravity and a phenomenological kind of dark energy (DE), which is known as QCD ghost dark energy. Since this kind of dark energy is not stable in the context of Einsteinian theory of gravity…

General Physics · Physics 2014-01-21 Kh. Saaidi , Ali. Aghamohammadi , B. Sabet , O. Farooq

This study investigates the potential of a cosmological model termed $\Lambda w$DM, in which a cosmological constant play the role of dark energy and dark matter is barotropic and has a constant equation of state parameter ($w_{\rm dm}$),…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-02 Yan-Hong Yao , Jian-Qi Liu

Combined measurements of Baryon Acoustic Oscillations (BAO) from the Dark Energy Spectroscopic Survey (DESI), the Cosmic Microwave Background (CMB) and Type Ia Supernovae (SN Ia), have recently challenged the $\Lambda$-Cold Dark Matter…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-10 Rayff de Souza , Agripino Sousa-Neto , Javier E. González , Jailson Alcaniz

Recent analyses have shown that a dynamic dark energy modeled by the CPL parameterization of the dark energy equation of state (EoS) can ease constraints on the total neutrino mass compared to the standard $\Lambda$CDM model. This helps…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-08 Gabriel Rodrigues , Rayff de Souza , Jamerson Rodrigues , Jailson Alcaniz

A model for a flat homogeneous and isotropic Universe composed of dark energy, dark matter, neutrinos, radiation and baryons is analyzed. The fields of dark matter and neutrinos are supposed to interact with the dark energy. The dark energy…

General Relativity and Quantum Cosmology · Physics 2008-11-26 G. M. Kremer

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

In the realm of thermodynamics of apparent horizon, we construct a dark energy (DE) model from 4-parameter generalized entropy of apparent horizon in a spatially non-flat universe. In particular, considering a non-zero spatial curvature of…

General Relativity and Quantum Cosmology · Physics 2025-04-07 Sergei D. Odintsov , Simone D'Onofrio , Tanmoy Paul

We study the holographic dark energy (HDE) model in generalized Brans-Dicke scenario with a non-minimal coupling between the scalar field and matter lagrangian namely Chameleon Brans Dicke (CBD) mechanism. In this study we consider the…

General Relativity and Quantum Cosmology · Physics 2014-07-02 K. Saaidi , H. Sheikhahmadi , T. Golanbari , S. W. Rabiei

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