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We scrutinized the Locally Rotational Symmetry (LRS) Bianchi type-I cosmological model in the presence of fractional holographic dark energy. We calculate the value of the Hubble parameter $H(z)$ using the field equations. After that, we…

General Relativity and Quantum Cosmology · Physics 2025-06-23 Shivangi Rathore , Elangbam Chingkheinganba Meetei , S. Surendra Singh

This study delves into the cosmological implications of the $f(Q,C)$ modified gravity framework within the context of the FLRW spacetime which offers a dynamic alternative to the standard $\Lambda$CDM cosmology. Here, we define the transit…

General Relativity and Quantum Cosmology · Physics 2024-12-03 N. Myrzakulov , Anirudh Pradhan , A. Dixit , S. H. Shekh

A 10\% difference in the scale for the Hubble parameter constitutes a clear problem for cosmology. Here, considering angular distribution of Type Ia supernovae (SN) within the Pantheon compilation and working within flat $\Lambda$CDM…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-23 Chethan Krishnan , Roya Mohayaee , Eoin Ó Colgáin , M. M. Sheikh-Jabbari , Lu Yin

Recently it has been noted by Di Valentino, Melchiorri and Silk (2019) that the enhanced lensing signal relative to that expected in the spatially flat $\Lambda$CDM model poses a possible crisis for the…

General Relativity and Quantum Cosmology · Physics 2020-08-12 Asta Heinesen , Thomas Buchert

We study the dark energy equation of state as a function of redshift in a non-parametric way, without imposing any {\it a priori} $w(z)$ (ratio of pressure over energy density) functional form. As a check of the method, we test our scheme…

Cosmology and Nongalactic Astrophysics · Physics 2014-03-05 Sergey Postnikov , Maria Giovanna Dainotti , Xavier Hernandez , Salvatore Capozziello

We use all available baryon acoustic oscillation distance measurements and Hubble parameter data to constrain the cosmological constant $\Lambda$, dynamical dark energy, and spatial curvature in simple cosmological models. We find that the…

Cosmology and Nongalactic Astrophysics · Physics 2018-07-19 Joseph Ryan , Sanket Doshi , Bharat Ratra

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

In this article, we study the expanding nature of universe in the contest of $f(R,L_m)$ gravity theory, here $ R $ represents the Ricci scalar and $ L_m $ is the matter Lagrangian density. With a specific form of $ f(R,L_m) $, we obtain the…

General Relativity and Quantum Cosmology · Physics 2023-06-28 J. K. Singh , Shaily , Ratbay Myrzakulov , Harshna Balhara

In this paper, a bouncing cosmological scenario is studied in the background of a flat FLRW model with a specific parametrized hyperbolic form of scale factor $ a $ in terms of $ t $, where $ \lambda $ is taken as the model parameter. This…

General Relativity and Quantum Cosmology · Physics 2022-08-12 J. K. Singh , Shaily , Kazuharu Bamba

We study a special running vacuum model (RVM) with $\Lambda = 3 \alpha H^2+3\beta H_0^4 H^{-2}+\Lambda_0$, where $\alpha$, $\beta$ and $\Lambda_0$ are the model parameters and $H$ is the Hubble one. This RVM has non-analytic background…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-31 Chao-Qiang Geng , Chung-Chi Lee , Lu Yin

In this study, we construct a theoretical framework based on the generalized Hubble parameter form which may arise within the particle creation, viscous and $f(R)$ gravity theory. The Hubble parameter is scrutinized for its compatibility…

General Relativity and Quantum Cosmology · Physics 2025-03-11 G. P. Singh , Romanshu Garg , Ashutosh Singh

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

Recent observational indications of an accelerating universe enhance the interest in studying models with a cosmological constant. We investigate cosmological expansion (FRW metric) with $\Lambda>0$ for a general linear equation of state…

Astrophysics · Physics 2009-11-07 A. S. Silbergleit

In this paper we compare data to theory. We use a compilation of the most recent cosmic microwave background (CMB) measurements to constrain Hubble's constant h, the baryon fraction Omega_b, and the cosmological constant lambda. We fit h-,…

Astrophysics · Physics 2008-02-03 Charles H. Lineweaver , Domingos Barbosa , Alain Blanchard , James G. Bartlett

The longstanding search for the cosmological model that best describes the Universe has been made more intriguing since the recent discovery of the Hubble constant, $H_{0}$, tension observed between the value of $H_{0}$ from the Cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2023-08-09 G. Bargiacchi , M. G. Dainotti , S. Capozziello

A novel function for modified gravity is proposed, $f(R, T)=R+\lambda R^2+2\beta\ln(T)$, with constants $\lambda$ and $\beta$, scalar curvature $R$, and the trace of stress energy tensor $T$, satisfying $T=\rho-3p>0$. Subsequently, two…

General Physics · Physics 2020-06-16 Emilio Elizalde , Nisha Godani , Gauranga C. Samanta

We study physical consequences of the Hubble expansion of FLRW manifold on measurement of space, time and light propagation in the local inertial frame. We analyse the solar system radar ranging and Doppler tracking experiments, and time…

Cosmology and Nongalactic Astrophysics · Physics 2015-01-23 Sergei Kopeikin

This paper delves into the late-time accelerated expansion of the universe and the evolution of cosmic structures within the context of a specific \( f(R, L_m) \) gravity model, formulated as \( f(R, L_m) = \lambda R + \beta L_m^\alpha +…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-05 Shambel Sahlu , Alnadhief H. A. Alfedeel , Amare Abebe

The Hubble constant ($H_0$) is one of the most important parameters in the standard $\rm \Lambda CDM$ model. The measurements given by the main two methods show a gap larger than $4\sigma$, which is known as Hubble tension. Fast radio…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-18 D. H. Gao , Q. Wu , J. P. Hu , S. X. Yi , X. Zhou , F. Y. Wang , Z. G. Dai

The Hubble constant ($H_0$), which represents the expansion rate of the Universe, is one of the most important cosmological parameters. The recent measurements of $H_0$ using the distance ladder methods such as Type Ia Supernovae (SNe Ia)…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-14 Rahul Kumar Thakur , Shashikant Gupta , Rahul Nigam , PK Thiruvikraman
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