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A new model of accelerating expansion of the universe is presented. A de Sitter solution in vacuum and a exact solution with the dust mater source are obtained. A new explanation of the acceleration of the cosmic expansion is given. In is…

General Physics · Physics 2013-01-16 G. Y. Chee

To describe dark energy we introduce a fluid model with no free parameter on the microscopic level. The constituents of this fluid are massless particles which are a dynamical realisation of the unextended $D=(3+1)$ Galilei algebra. These…

Cosmology and Nongalactic Astrophysics · Physics 2009-10-29 P. C. Stichel , W. J. Zakrzewski

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 study noncommutative classical Friedmann-Robertson-Walker cosmological models. The constant curvature of the spatial sections can be positive ($k=1$), negative ($k=-1$) or zero ($k=0$). The matter is represented by a perfect fluid with…

General Relativity and Quantum Cosmology · Physics 2017-01-06 G. Oliveira-Neto , A. R. Vaz

In order to try explaining the present accelerated expansion of the universe, we consider the most complete noncommutativity, of a certain type, in a Friedmann-Robertson-Walker cosmological model, coupled to a perfect fluid. We use the ADM…

General Relativity and Quantum Cosmology · Physics 2021-06-23 G. Oliveira-Neto , L. Fazza Marcon

We propose a new pressure-parametrization model to explain the accelerated expansion of the late-time Universe by considering the dark contents (dark matter and dark energy) as a unified dark fluid. To realize this model more physically, we…

Cosmology and Nongalactic Astrophysics · Physics 2017-05-30 Deng Wang , Yang-Jie Yan , Xin-He Meng

Phantom dark energy from DESI DR2 BAO [1]-[3] and bservations of Supermassive Black Hole (SMBH) at very high redshift present two new challenges in cosmology and astrophysics. In this work, we show that both problems can be addressed by…

Astrophysics of Galaxies · Physics 2026-05-07 James C. C. Wong

In the present work we discuss a third alternative to explain the latest observational data concerning the accelerating Universe and its different stages. The particle creation mechanism in the framework of non-equilibrium thermodynamics is…

General Relativity and Quantum Cosmology · Physics 2016-05-17 Subenoy Chakraborty , Supriya Pan , Subhajit Saha

In this article, we introduce an innovative parametric representation of the Hubble parameter, providing a model-independent means to explore the dynamics of an accelerating cosmos. The model's parameters are rigorously constrained through…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-16 M. Koussour , N. Myrzakulov , M. K. M. Ali

In view of late-time cosmic acceleration, a dark energy cosmological model is revisited wherein Einstein's cosmological constant is considered as a candidate of dark energy. Exact solution of Einstein field equations (EFEs) is derived in a…

General Relativity and Quantum Cosmology · Physics 2019-11-22 S. K. J. Pacif , Md Salahuddin Khan , L. K. Paikroy , Shalini Singh

The deceleration parameter q as the diagnostic of the cosmological accelerating expansion is investigated. By expanding the luminosity distance to the fourth order of redshift and the so-called y-redshift in two redshift bins and fitting…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Ronggen Cai , Zhongliang Tuo

We continue our presentation of an alternative cosmology based on conformal gravity, following our kinematical approach introduced in a recent paper. In line with the assumptions of our model, which proposes a closed-form expression for the…

Astrophysics · Physics 2011-09-28 Gabriele U. Varieschi

The {\it{Cosmological Boundary Flux Parameter}} is a novel proposal that attempts to explain the origin of the cosmological parameter $\Lambda$ purely by geometric nature. Then we implement this new approach to a flat FLRW universe along…

General Relativity and Quantum Cosmology · Physics 2022-12-29 Rafael Hernández-Jiménez , Claudia Moreno , Mauricio Bellini , C. Ortiz

On the basis of a previously established scalar-tensor extension of the $\Lambda$CDM model we develop an effective fluid approach for the matter growth function. This extended $\Lambda$CDM (henceforth $e_{\Phi}\Lambda$CDM) cosmology takes…

Cosmology and Nongalactic Astrophysics · Physics 2019-05-01 W. Zimdahl , H. E. S. Velten , W. C. Algoner

We present a new $f(Q)$ cosmological model capable of reproducing late-time acceleration, i.e. $f\left( Q\right) = \lambda_{0}\left( \lambda +Q\right) ^{n}$ by supporting certain parametrization of the Hubble parameter. By using…

General Relativity and Quantum Cosmology · Physics 2023-06-26 N. Myrzakulov , M. Koussour , Dhruba Jyoti Gogoi

A quantum expansion parameter, analogous to the Hubble parameter in cosmology, is defined for a free particle quantum wavefunction. By considering the universe as an initial single Gaussian quantum wavepacket whose mass is that of…

Cosmology and Nongalactic Astrophysics · Physics 2012-02-28 A. D. Ernest

There is mounting observational evidence that the expansion of our Universe is undergoing a late-time acceleration. Among many proposals to describe this phenomenon, the cosmological constant seems to be the simplest and the most natural…

Astrophysics · Physics 2010-03-19 S. Carneiro , C. Pigozzo , H. A. Borges , J. S. Alcaniz

The acceleration of the cosmic expansion has been discovered as a consequence of redshift Supernovae data. In the usual way, this cosmic acceleration is explained by the presence of a positive cosmological constant or quantum vacuum energy,…

General Relativity and Quantum Cosmology · Physics 2007-05-23 J. -F. Pascual-Sánchez

We investigate late-time cosmology in the context of modified $f(Q,L_m)$ gravity, considering a non-linear model$ f(Q,L_m) = \alpha Q + \beta L_m^n + \lambda$ where, $\alpha$, $\beta$, $\lambda$, and $n$ are some free parameters. The…

General Relativity and Quantum Cosmology · Physics 2026-01-16 Rajdeep Mazumdar , Kalyan Malakar , Kalyan Bhuyan

Directly comparing the 6 expansion rate measured by type Ia supernovae data and the lower bound on the expansion rate set by the strong energy conditions or the null hypothesis that there never exists cosmic acceleration, we see $3\sigma$…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-06 Yingjie Yang , Yungui Gong
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