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One of the most compelling tasks of modern cosmology is to constrain the expansion history of the Universe, since this measurement can give insights on the nature of dark energy and help to estimate cosmological parameters. In this letter…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-24 Michele Moresco

We perform a validation of estimates of the growth rate of structure, described by the parameter combination $f\sigma_8$, in modified gravity cosmologies. We consider an analysis pipeline based on the redshift-space distortion modelling of…

Cosmology and Nongalactic Astrophysics · Physics 2016-11-08 Alexandre Barreira , Ariel G. Sánchez , Fabian Schmidt

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

Modified gravity has attracted much attention over the last few years and remains a potential candidate for dark energy. In particular, the so-called viable f(R) gravity theories, which are able to both recover General Relativity (GR) and…

General Relativity and Quantum Cosmology · Physics 2016-04-20 Alvaro de la Cruz-Dombriz , Peter K. S. Dunsby , Sulona Kandhai , Diego Saez-Gomez

Considering a well-motivated $f(R)$ modified-gravity model, in which an exponential function of the curvature is included, in this paper we implement a statistical data analysis to set constraints on the parameters of the model, taking into…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-01 Mario A. Acero , A. Oliveros

We investigated a bulk viscous fluid universe with cosmological constant {\Lambda} by assuming that the bulk viscosity to be proportional to the Hubble parameter. We found that for an expanding universe, the (relative) matter density will…

General Relativity and Quantum Cosmology · Physics 2024-01-25 Jinwen Hu , Huan Hu

Measurements of the Hubble constant, and more generally measurements of the expansion rate and distances over the interval $0 < z < 1$, appear to be inconsistent with the predictions of the standard cosmological model ($\Lambda$CDM) given…

Cosmology and Nongalactic Astrophysics · Physics 2020-03-04 Lloyd Knox , Marius Millea

We consider a minimal fractional deformation of Newtonian gravity characterized by a single parameter $\alpha$. In the limit $\alpha \to 1$, the theory reduces to standard Newtonian gravity. Previous works showed that the $\Lambda$CDM…

General Relativity and Quantum Cosmology · Physics 2026-03-18 S. M. M. Rasouli

The concept of a rapidly sign-switching cosmological constant, interpreted as a mirror AdS-dS transition in the late universe and known as the $\Lambda_{\rm s}$CDM, has significantly improved the fit to observational data, offering a…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-31 Mateus S. Souza , Ana M. Barcelos , Rafael C. Nunes , Özgür Akarsu , Suresh Kumar

We consider cosmic chronometer (CC) data for the Hubble parameter, quasar (QSO) luminosities data of X-rays and ultraviolet rays emission, and the latest measurements of the present value of the Hubble parameter from 2018 Planck mission…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-29 Bikash R. Dinda , Haveesh Singirikonda , Subhabrata Majumdar

Scalar-tensor theories have shown great potential in inducing tailored modifications compared to cosmic evolution in the $\Lambda$CDM model. We reconsider quintessence models in this work in the context of three driving potentials. We…

General Relativity and Quantum Cosmology · Physics 2025-04-11 L. K. Duchaniya , Jackson Levi Said , B. Mishra

In this paper we study the viability of an entropic cosmological model. The effects of entropic gravity are derived from a modified entropy-area relationship with a volumetric entropy term. This model describes a late time limit cosmic…

General Relativity and Quantum Cosmology · Physics 2024-03-07 Javier Chagoya , I. Díaz-Saldaña , J. C. López-Domínguez , M. Sabido

In this paper, we investigate the freezing quintessence scenario in late-time cosmic expansion using a non-linear $f(R, L_m)$ gravity model, $f(R,L_m)=\frac{R}{2}+L_m^\alpha$, where $\alpha$ is a free parameter. We consider a solution for…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-17 Yerlan Myrzakulov , M. Koussour , A. Caliskan , E. Güdekli , S. Muminov , J. Rayimbaev

In this paper, a cosmological model of the Universe is presented in $f(Q,T)$ gravity and the parameters are constrained by cosmological data sets. Initially, a generalised form of $f(Q,T)$ model is used as $f(Q,T)=-\lambda_{1}…

General Relativity and Quantum Cosmology · Physics 2024-03-21 A. S. Agrawal , B. Mishra , S. K. Tripathy

We use updated Hubble parameter and baryon acoustic oscillation data, as well as other lower-redshift Type Ia supernova, Mg II reverberation-measured quasar, quasar angular size, H II starburst galaxy, and Amati-correlated gamma-ray burst…

Cosmology and Nongalactic Astrophysics · Physics 2022-05-31 Shulei Cao , Bharat Ratra

In this letter, we study the cosmological dynamics of steeper potential than exponential. Our analysis shows that a simple extension of an exponential potential allows to capture late-time cosmic acceleration and retain the tracker…

General Relativity and Quantum Cosmology · Physics 2018-02-02 M. Shahalam , Weiqiang Yang , R. Myrzakulov , Anzhong Wang

Cosmology has entered an era of unprecedented precision, yet increasing accuracy has revealed cracks in the standard $\Lambda$CDM paradigm. Although the model remains highly successful when confronted with individual datasets, joint…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-06 Eleonora Di Valentino

This paper explores models of the FLRW universe that incorporate a time-varying cosmological term $\Lambda(t)$. Specifically, we assume a power-law form for the cosmological term as a function of the scale factor: $\Lambda(t)=\Lambda_{0}…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-14 M. Koussour , N. Myrzakulov , J. Rayimbaev

Dynamical aspects of cosmological model in an extended gravity theory have been investigated in the present work. We have adopted a simplified approach to obtain cosmic features, which in fact requires more involved calculations. A…

General Relativity and Quantum Cosmology · Physics 2021-06-10 B. Mishra , S. K. Tripathy , Sankarsan Tarai

There has been a significant interest in modifications of the standard $\Lambda$ Cold Dark Matter ($\Lambda$CDM) cosmological model prompted by tensions between certain datasets, most notably the Hubble tension. The late-time modifications…

Cosmology and Nongalactic Astrophysics · Physics 2022-12-06 Levon Pogosian , Marco Raveri , Kazuya Koyama , Matteo Martinelli , Alessandra Silvestri , Gong-Bo Zhao , Jian Li , Simone Peirone , Alex Zucca