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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

We investigate a four-parameter entropic dark energy model in a spatially curved FLRW universe, based on a generalized entropy-area relation at the apparent horizon. While the proposed entropy function captures a broad class of…

General Relativity and Quantum Cosmology · Physics 2025-11-21 Davood Momeni

The holographic cut-off in generalized dark energy (HDE) formalism depends on its cut-off. Following this, a four-parameter generalized entropy has recently been developed. It reduces to various known entropies for appropriate parameter…

General Physics · Physics 2025-10-08 Sanghati Saha , Ertan Güdekli , Surajit Chattopadhyay

We investigate a dark energy (DE) equation of state (EoS) parametrization in a curved spacetime using current observations. We constrain the model parameters by using observational Hubble data from Cosmic Chronometer (CC), Pantheon Plus…

General Physics · Physics 2026-05-13 D. Revanth Kumar , Santosh Kumar Yadav

In this work we examine the possibility that the dark energy (DE) density, $\rho_{de}$ can be dynamical and appear as a power series expansion of the Hubble rate (and its derivatives), i.e.$\rho_{de}(H,\dot{H},...)$. For the present…

General Relativity and Quantum Cosmology · Physics 2019-07-30 Mehdi Rezaei , Mohammad Malekjani , Joan Sola

This paper introduces the class of omnipotent dark energy (DE) models characterized by nonmonotonic energy densities that are capable of attaining negative values with corresponding equation of state parameters featuring phantom divide line…

Cosmology and Nongalactic Astrophysics · Physics 2024-01-25 Shahnawaz A. Adil , Ozgur Akarsu , Eleonora Di Valentino , Rafael C. Nunes , Emre Ozulker , Anjan A. Sen , Enrico Specogna

Classical and quantum entropic properties of holographic dark energy (HDE) are considered in view of the fact that its entropy is far more restrictive than the entropy of a black hole of the same size. In cosmological settings (in which HDE…

General Relativity and Quantum Cosmology · Physics 2008-11-26 R. Horvat

Recently, the vacuum energy of the QCD ghost in a time-dependent background is proposed as a kind of dark energy candidate to explain the acceleration of the Universe. In this model, the energy density of the dark energy is proportional to…

High Energy Physics - Theory · Physics 2012-10-03 Chao-Jun Feng , Xin-Zhou Li , Xian-Yong Shen

In the original holographic dark energy (HDE) model, the dark energy density is proposed to be $\rho_{de} = 3c^2M^2_{pl}L^{-2}$, with $c$ is a dimensionless constant characterizing the properties of the HDE. In this work, we propose the…

Cosmology and Nongalactic Astrophysics · Physics 2012-06-25 Zhenhui Zhang , Miao Li , Xiao-Dong Li , Shuang Wang , Wen-Shuai Zhang

So far, there have been no theories or observational data that deny the presence of interaction between dark energy and dark matter. We extend naturally the holographic dark energy (HDE) model, proposed by Granda and Oliveros, in which the…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Fei Yu , Jingfei Zhang , Jianbo Lu , Wei Wang , Yuanxing Gui

Early dark energy (EDE) that behaves like a cosmological constant at early times (redshifts $z\gtrsim3000$) and then dilutes away like radiation or faster at later times can solve the Hubble tension. In these models, the sound horizon at…

Cosmology and Nongalactic Astrophysics · Physics 2019-06-12 Vivian Poulin , Tristan L. Smith , Tanvi Karwal , Marc Kamionkowski

We present a Bayesian comparative analysis of five cosmological models: $\Lambda$CDM, $w$CDM, $w_0w_a$CDM, $\phi$CDM (with scalar-field dark energy), and an interacting dark energy scenario (the $\xi$-index model), to investigate dark…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-19 Zhuoming Zhang , Tengpeng Xu , Yun Chen

We study a cosmological model based on the holographic principle that allows an interaction between dark energy and dark matter with a Hubble infrared cutoff. We adopt an agnostic point of view with respect to the form of the interaction…

General Relativity and Quantum Cosmology · Physics 2022-02-22 Celia Escamilla-Rivera , Aldo Gamboa

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

We determine the Hubble expansion and the general cosmic perturbations equations for a general system consisting of self-conserved matter and self-conserved dark energy (DE). While at the background level the two components are…

General Relativity and Quantum Cosmology · Physics 2016-01-13 Adria Gomez-Valent , Elahe Karimkhani , Joan Sola

In this article, we review a series of recent theoretical results regarding a conventional approach to the dark energy (DE) concept. This approach is distinguished among others for its simplicity and its physical relevance. By compromising…

Cosmology and Nongalactic Astrophysics · Physics 2016-04-20 Kostas Kleidis , Nikolaos K. Spyrou

Recently, the R\'{e}nyi and Tsallis generalized entropies have extensively been used in order to study various cosmological and gravitational setups. Here, using a special type of generalized entropy, a generalization of both the R\'{e}nyi…

General Relativity and Quantum Cosmology · Physics 2018-04-05 A. Sayahian Jahromi , S. A. Moosavi , H. Moradpour , J. P. Morais Graça , I. P. Lobo , I. G. Salako , A. Jawad

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

In this work, we present two generalized formulations of the Holographic and Ricci Dark Energy (DE) models, given by $ \rho_{GH} = 3c^2M^{2}_{pl} \left[ 1-\epsilon\left(1-\frac{R}{H^2}\right) \right]H^2$ and $\rho_{GR} =…

General Relativity and Quantum Cosmology · Physics 2025-10-29 Antonio Pasqua

In this work, we first discuss the possibility that dark energy models with negative energy density values in the past can alleviate the $H_0$ tension, as well as the discrepancy with the baryon acoustic oscillation (BAO) Lyman-$\alpha$…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-09 Giovanni Acquaviva , Ozgur Akarsu , Nihan Katirci , J. Alberto Vazquez
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