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Soft cosmology is an extension of standard cosmology allowing for a scale-dependent equation-of-state (EoS) parameter in the dark sectors, which is one of the properties of soft materials in condensed-matter physics, that may arise either…

Cosmology and Nongalactic Astrophysics · Physics 2022-12-12 Emmanuel N. Saridakis , Weiqiang Yang , Supriya Pan , Fotios K. Anagnostopoulos , Spyros Basilakos

We propose a novel parameterization of the dark energy density. It is particularly well suited to describe a non-negligible contribution of dark energy at early times and contains only three parameters, which are all physically meaningful:…

Astrophysics · Physics 2007-05-23 Michael Doran , Georg Robbers

The present work is based upon a parametric reconstruction of the effective or total equation of state in a model for the universe with accelerated expansion. The constraints on the model parameters are obtained by maximum likelihood…

Cosmology and Nongalactic Astrophysics · Physics 2016-05-27 Ankan Mukherjee

Observational constraints are considered on a $w_{log}$CDM model of the dark energy equation of state, $w_{d}(z) = w_{0} + w_{a}\left( \frac{\ln(2+z)}{1+z} - \ln 2 \right)$, using the most recent cosmological datasets including DESI Baryon…

General Physics · Physics 2026-03-10 Saurabh Verma , Archana Dixit , Anirudh Pradhan , M. S. Barak

We introduce a modified form of the Phenomenologically Emergent Dark Energy (PEDE) model by showing a very elegant approach. The model is named as Modified Emergent Dark Energy (MEDE) to distinguish from PEDE model and it includes…

General Relativity and Quantum Cosmology · Physics 2020-08-24 H. B. Benaoum , Weiqiang Yang , Supriya Pan , Eleonora Di Valentino

In this study, we investigate the oscillatory dark energy model $w_{\sin}\mathrm{CDM}$ based on the DESI BAO data together with OHD, Pantheon Plus, and SH0ES measurements. We examine how the DESI data influence the dark energy…

General Physics · Physics 2026-02-06 Manish Yadav , Archana Dixit , M. S. Barak , Anirudh Pradhan

A large number of cosmological parameters have been suggested for obtaining information on the nature of dark energy. In this work, we study the efficacy of these different parameters in discriminating theoretical models of dark energy,…

Cosmology and Nongalactic Astrophysics · Physics 2010-12-08 Alexander V. Pan , Ujjaini Alam

Recent observations from the DESI survey have reignited the debate on the true nature of dark energy, challenging the standard model of cosmology. The results suggest a preference for dynamical dark energy rather than a constant. Several…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-28 Ramanpreet Singh , Athul CN , H. K. Jassal

The present work is based on the holographic dark energy model with Hubble horizon as the infrared cut-off. The interaction rate between dark energy and dark matter has been reconstructed for three different parameterizations of the…

Cosmology and Nongalactic Astrophysics · Physics 2016-11-28 Ankan Mukherjee

We reconstruct evolution of the dark energy (DE) density using a nonparametric Bayesian approach from a combination of latest observational data. We caution against parameterizing DE in terms of its equation of state as it can be singular…

Cosmology and Nongalactic Astrophysics · Physics 2018-12-12 Yuting Wang , Levon Pogosian , Gong-Bo Zhao , Alex Zucca

We conduct a Bayesian analysis of recent observational datasets, specifically the Cosmic Chronometers (CC) dataset and Pantheon samples, to investigate the evolution of the EoS parameter in dark energy models. Our study focused on the…

Cosmology and Nongalactic Astrophysics · Physics 2023-09-29 N. Myrzakulov , M. Koussour , Alnadhief H. A. Alfedeel , Amare Abebe

We investigate whether the current Hubble parameter $H(z)$ measurements could help improve the constraints on dark energy on the basis of the mainstream cosmological probes including the type Ia supernovae (SN) observation, the cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2019-05-16 Yan Liu , Rui-Yun Guo , Jing-Fei Zhang , Xin Zhang

Constraining the dark energy deceleration parameter is one of the fascinating topics in the recent cosmological paradigm. This work aims to reconstruct the dark energy using parametrization of the deceleration parameter in a flat FRW…

General Relativity and Quantum Cosmology · Physics 2023-09-26 Amine Bouali , Himanshu Chaudhary , Ujjal Debnath , Alok Sardar , G. Mustafa

We constrain a unified dark matter (UDM) model from the latest observational data. This model assumes that the dark sector is degenerate. Dark energy and dark matter are the same component. It can be described by an affine equation of state…

Cosmology and Nongalactic Astrophysics · Physics 2012-12-11 Kai Liao , Shuo Cao , Jun Wang , Xiaolong Gong , Zong-Hong Zhu

We constrain the evolution of dark matter energy density over time, specifically focusing on deviation from the standard model represented by the equation $\rho_{m}\propto(1+z)^{3-\varepsilon}$, where $\varepsilon$ is a constant parameter.…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-30 Yupeng Yang , Xinyi Dai , Yicheng Wang

Gaussian processes (GP) provide an elegant and model-independent method for extracting cosmological information from the observational data. In this work, we employ GP to perform a joint analysis by using the geometrical cosmological probes…

Cosmology and Nongalactic Astrophysics · Physics 2021-02-11 Alexander Bonilla , Suresh Kumar , Rafael C. Nunes

In this manuscript, we investigate the constraints on dynamical vacuum models within the framework of $\Lambda(t)$CDM cosmology by assuming a parameterization of the vacuum energy density as $\rho_{\Lambda}(t)=\rho_{\Lambda 0} \left[1 +…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-14 Yerlan Myrzakulov , M. Koussour , M. Bulanbay , S. Muminov , J. Rayimbaev

We consider a 12-parameter cosmological model with non-phantom dynamical dark energy (NPDDE), where non-phantom implies that the equation of state (EoS) of dark energy (DE), $w(z)\geq-1$ for all redshifts $z$. Thus, the DE EoS covers the…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-20 Shouvik Roy Choudhury , Teppei Okumura , Keiichi Umetsu

Measurements of the current expansion rate of the Universe, $H_0$, using standard candles, disagree with those derived from observations of the Cosmic Microwave Background (CMB). This discrepancy, known as the Hubble tension, is substantial…

Cosmology and Nongalactic Astrophysics · Physics 2024-02-05 Sergio Torres-Arzayus

The new Dark Energy Spectroscopic Instrument (DESI) DR2 results have strengthened the possibility that dark energy is dynamical, i.e., it has evolved over the history of the Universe. One simple, but theoretically well motivated and widely…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-14 Yashar Akrami , George Alestas , Savvas Nesseris
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