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We explore a cosmological model based on R\'enyi entropic corrections to the Friedmann equations and constrain it using DESI, P-BAO, CC, and gravitational-wave observations. Unlike earlier works, we obtain a direct and stringent constraint…

General Relativity and Quantum Cosmology · Physics 2026-04-27 Rajdeep Mazumdar , Kalyan Malakar , Kalyan Bhuyan

In this work, we investigate the cosmological dynamics of an anisotropic Universe within the framework of $f(R,T)$ gravity by incorporating pressureless dark matter and the dark energy models. The analysis is carried out in a Bianchi type-I…

General Relativity and Quantum Cosmology · Physics 2026-05-13 S. H. Shekh , N. Myrzakulov , Anirudh Pradhan , M. Zeyauddin

The presence of inhomogeneities modifies the cosmic distances through the gravitational lensing effect, and, indirectly, must affect the main cosmological tests. Assuming that the dark energy is a smooth component, the simplest way to…

Astrophysics · Physics 2008-11-26 R. C. Santos , J. V. Cunha , J. A. S. Lima

We investigate a modified cosmological model aimed at addressing the Hubble tension, considering revised dynamics in the late Universe. The model introduces a parameter $c$ affecting the evolution equations, motivated by a modified Poisson…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-13 Luis A. Escamilla , Donatella Fiorucci , Giovanni Montani , Eleonora Di Valentino

A spatially homogeneous anisotropic LRS Bianchi type-I cosmological model is studied in $f(R,T)$ gravity with a special form of Hubble's parameter, which leads to constant deceleration parameter. The parameters involved in the considered…

General Relativity and Quantum Cosmology · Physics 2022-07-20 Binaya K. Bishi , S. K. J. Pacif , P. K. Sahoo , G. P. Singh

This work examines the cosmological implications of two functional forms of $f(R,T) = R + \alpha T^n$ gravity: for two different value of $n $ where $n=1$ and $n\neq 1$, and $\alpha$ and $n$ are free parameters. The modified Friedmann…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-24 Mustapha Lamaaoune

We probe the cosmic acceleration by using the recently released SNLS3 sample of 472 type Ia supernovae. Combining this type Ia supernovae dataset with the cosmic microwave background anisotropy data from the Wilkinson Microwave Anisotropy…

Cosmology and Nongalactic Astrophysics · Physics 2011-07-14 Xiao-Dong Li , Song Li , Shuang Wang , Wen-Shuai Zhang , Qing-Guo Huang , Miao Li

Decaying vacuum cosmological models evolving smoothly between two extreme (very early and late time) de Sitter phases are capable to solve or at least to alleviate some cosmological puzzles, among them: (i) the singularity, (ii) horizon,…

General Relativity and Quantum Cosmology · Physics 2018-07-26 G. J. M. Zilioti , R. C. Santos , J. A. S. Lima

We investigate a dynamical reconstruction of the dark energy equation of state parameter by assuming that it satisfies a law of motion described by an autonomous second-order differential equation, with the limit of the cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-25 Andronikos Paliathanasis

Using the Einstein-Hilbert approximation of asymptotically safe quantum gravity we present a consistent renormalization group based framework for the inclusion of quantum gravitational effects into the cosmological field equations. Relating…

High Energy Physics - Theory · Physics 2009-11-11 M. Reuter , F. Saueressig

In this paper, we have proposed a model of accelerating Universe with binary mixture of bulk viscous fluid and dark energy. and probed the model parameters: present values of Hubble's constant $H_{0}$, Equation of state paper of dark energy…

General Relativity and Quantum Cosmology · Physics 2021-08-18 Nishant Singla , M. K. Gupta , Anil Kumar Yadav , G. K. Goswami

We compile a complete collection of reliable Hubble parameter $H(z)$ data to redshift $z \leq 2.36$ and use them with the Gaussian Process method to determine continuous $H(z)$ functions for various data subsets. From these continuous…

Cosmology and Nongalactic Astrophysics · Physics 2018-04-04 Hai Yu , Bharat Ratra , Fa-Yin Wang

The possibility that we live in a special place in the universe, close to the centre of a large void, seems an appealing alternative to the prevailing interpretation of the acceleration of the universe in terms of a LCDM model with a…

Astrophysics · Physics 2009-06-23 Juan Garcia-Bellido , Troels Haugboelle

Extending the standard $\Lambda$CDM model by considering dissipative effects within a causal viscous framework, and obtaining an analytical solution for the Hubble parameter remains a challenge in the literature. In this work, we resolve…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-29 Vishnu A Pai , Sarath N , Titus K Mathew

In this paper we have investigated a bulk viscous universe in $f(R,T)$ gravity where $R$ and $T$ are the Ricci scalar and trace of energy momentum tensor respectively. We have obtained explicit solutions of field equations in modified…

General Physics · Physics 2020-03-03 Anil Kumar Yadav , Lokesh Kumar Sharma , B. K. Singh , P. K. Sahoo

We bring forward a generalized pressure dark energy (GPDE) model to explore the evolution of the universe. This model has covered three common pressure parameterization types and can be reconstructed as quintessence and phantom scalar…

Cosmology and Nongalactic Astrophysics · Physics 2019-10-23 Jun-Chao Wang , Xin-He Meng

The inhomogeneous distribution of matter in the non-linear regime of galaxies, clusters of galaxies and voids is described by an exact, spherically symmetric inhomogeneous solution of Einstein's gravitational field equations, corresponding…

Astrophysics · Physics 2009-11-11 J. W. Moffat

Despite the broad successes of the flat $\Lambda$CDM model and its fitness to the various cosmological observations, it confronts challenges stemming from anomalies in the measurements of the Hubble constant ($H_0$) and the amplitude of…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-28 Saeed Pourojaghi , Mohammad Malekjani

Cosmic acceleration is widely believed to require either a source of negative pressure (i.e., dark energy), or a modification of gravity, which necessarily implies new degrees of freedom beyond those of Einstein gravity. In this paper we…

High Energy Physics - Theory · Physics 2017-06-28 Lasha Berezhiani , Justin Khoury , Junpu Wang

As one of the possible extensions of Einstein's General Theory of Relativity, it has been recently suggested that the presence of spacetime torsion could solve problems of the very early and the late-time universe undergoing accelerating…

Cosmology and Nongalactic Astrophysics · Physics 2024-02-19 Tonghua Liu , Ziqiang Liu , Jiamin Wang , Shengnan Gong , Man Li , Shuo Cao