English
Related papers

Related papers: A flat FRW model with dynamical $\Lambda$ as funct…

200 papers

In this paper, we have presented a bouncing cosmological model of the Universe in an extended theory of gravity. The dynamical behaviour of the model obtained from the flat FLRW space-time along with the violation of null energy condition…

General Relativity and Quantum Cosmology · Physics 2022-04-22 A. S. Agrawal , Francisco Tello-Ortiz , B. Mishra , S. K. Tripathy

In this paper, we present an accelerating cosmological model by constraining the free parameters using the cosmological datasets in an extended symmetric teleparallel gravity for the flat and anisotropic space-time. We employ a time…

General Relativity and Quantum Cosmology · Physics 2023-06-27 S. A. Narawade , M. Koussour , B. Mishra

Some properties of cosmological models with a time variable bulk viscous coefficient in presence of adiabatic mater creation and G, c, Lambda variables are investigated in the framework of flat FRW line element. We trivially find a set of…

General Relativity and Quantum Cosmology · Physics 2015-06-25 J. A. Belinchon

We study the decay of solutions of the wave equation in some expanding cosmological spacetimes, namely flat Friedmann-Lema\^itre-Robertson-Walker (FLRW) models and the cosmological region of the Reissner-Nordstr\"om-de Sitter (RNdS)…

General Relativity and Quantum Cosmology · Physics 2020-05-06 João L. Costa , José Natário , Pedro Oliveira

Choosing the three phenomenological models of the dynamical cosmological term $\Lambda$, viz., $\Lambda \sim (\dot a/a)^2$, $\Lambda \sim {\ddot a/a}$ and $\Lambda \sim \rho$ where $a$ is the cosmic scale factor, it has been shown by the…

General Relativity and Quantum Cosmology · Physics 2009-09-28 Saibal Ray , P. C. Ray , Partha Pratim Ghosh , Utpal Mukhopadhyay , Partha Chowdhury

We have investigated some bouncing cosmological models in an isotropic and homogeneous space time with the F(R) theory of gravity. Two functional forms of F(R) have been investigated with a bouncing scale factor. The dynamical parameters…

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

We place observational constraints on an FLRW cosmological model in $f(R,L_m)$ gravity with a specific deceleration parameter that depends on the scale factor. This form of the deceleration parameter has been discussed by authors in several…

General Relativity and Quantum Cosmology · Physics 2024-12-30 Aroonkumar Beesham

We investigate some properties of flat cosmological models with a $\Lambda$ term that decreases with time as $\Lambda \propto a^{-m}$ (a is the scale factor and m is a parameter $0\leq m < 3$). The models are equivalent to standard…

Astrophysics · Physics 2009-10-30 V. Silveira , I. Waga

We construct a compact phase space for flat FLRW spacetimes with standard matter described by a perfect fluid with a barotropic equation of state for general f(R) theories of gravity, subject to certain conditions on the function f. We then…

General Relativity and Quantum Cosmology · Physics 2015-06-03 Mohamed Abdelwahab , Rituparno Goswami , Peter K. S. Dunsby

We present a systematic analysis of the dynamics of flat Friedmann-Lema\^{i}tre-Robertson-Walker cosmological models with radiation and dust matter in generalized teleparallel $f(T)$ gravity. We show that the cosmological dynamics of this…

General Relativity and Quantum Cosmology · Physics 2017-09-05 Manuel Hohmann , Laur Jarv , Ulbossyn Ualikhanova

This article explores the cosmological scenario of the universe in the context of the $f(T)$ power law model, where $T$ represent the torsion scalar. To obtain the deterministic solution of the field equations we parametrized the effective…

General Relativity and Quantum Cosmology · Physics 2024-11-11 S. R. Bhoyar , Yash B. Ingole

We investigate the dynamics of the generalized $\Lambda$CDM model, which the $\Lambda$ term is running with the cosmological time. The $\Lambda(t)$ term emerges from the covariant theory of the scalar field $\phi$ with the self-interacting…

Cosmology and Nongalactic Astrophysics · Physics 2017-09-29 Marek Szydlowski , Aleksander Stachowski

Cosmological models in Lyra's geometry are constructed and investigated with the assumption of a minimal interaction of matter with the displacement vector field and the dynamical $\Lambda$ - term. Exact solutions of the model equations are…

General Relativity and Quantum Cosmology · Physics 2012-10-04 V. K. Shchigolev

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 take a phenomenological approach to study the cosmological evolution of decaying vacuum cosmology ($\Lambda(t)$CDM) based on a simple assumption about the form of the modified matter expansion rate. In this framework, almost all the…

Astrophysics · Physics 2009-11-10 Peng Wang , Xin-He Meng

In this manuscript, we present a number of fascinating explicit reconstructions for the $f(Q)$ gravity from the background of Friedmann-La\^imatre-Robertson-Walker (FLRW) evolution history. We find the more general functions of…

General Relativity and Quantum Cosmology · Physics 2022-10-25 Gaurav N. Gadbail , Sanjay Mandal , P. K. Sahoo

Nowadays, according to the observational evidences the curvature parameter of the universe is neglected and spatially flat FLRW model is on the top of interest for cosmologists. However, due to some discrepancies between $\Lambda$-CDM model…

General Relativity and Quantum Cosmology · Physics 2021-09-30 Ali A. Asgari , Amir H. Abbassi

The $f(T)$ gravity is one of the extensions of teleparallel equivalent of general relativity, in which more general functions of the torsion scalar $T$ can be described. With the proposed functional form of $f(T) = \alpha T - \beta u^{-n} +…

General Relativity and Quantum Cosmology · Physics 2026-04-14 Suraj Kumar Behera , S. A. Kadam , Pratik P. Ray , B. Mishra

We address the question of the uniqueness of spatially flat $\Lambda$CDM-like evolution for FLRW cosmologies in General Relativity, i.e. whether any model other than the spatially flat $\Lambda$CDM can give rise to the same type of scale…

General Relativity and Quantum Cosmology · Physics 2024-03-21 Saikat Chakraborty , Daniele Gregoris , B. Mishra

In this research paper, we explore a well-motivated parametrization of the time-dependent deceleration parameter, characterized by a cubic form, within the context of late time cosmic acceleration. The current analysis is based on the…

General Relativity and Quantum Cosmology · Physics 2023-12-19 Madhur Khurana , Himanshu Chaudhary , Saadia Mumtaz , S. K. J. Pacif , G. Mustafa