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FRW models of the universe have been studied in the cosmological theory based on Lyra's manifold. A new class of exact solutions has been obtained by considering a time dependent displacement field for variable deceleration parameter from…

General Relativity and Quantum Cosmology · Physics 2015-06-25 A. Pradhan , J. P. Shahi , C. B. Singh

We propose a new law for the deceleration parameter that varies linearly with time and covers Berman's law where it is constant. Our law not only allows one to generalize many exact solutions that were obtained assuming constant…

General Relativity and Quantum Cosmology · Physics 2012-01-25 Ozgur Akarsu , Tekin Dereli

In this article we have presented FRW cosmological model in the framework of Brans-Dicke theory. This paper deals with a new proposed form of deceleration parameter and cosmological constant. The effect of bulk viscosity is also studied in…

General Relativity and Quantum Cosmology · Physics 2017-07-27 G. P. Singh , Binaya K. Bishi

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

Confirmation of accelerated expansion of the universe probed the concept of dark energy theory, and since then, numerous models have been introduced to explain its origin and nature. The present work is based on reconstructing dark energy…

General Relativity and Quantum Cosmology · Physics 2023-10-09 Himanshu Chaudhary , Amine Bouali , Ujjal Debnath , Tanusree Roy , G. Mustafa

The paper deals with a spatially homogeneous and isotropic FRW space-time filled with perfect fluid and dark energy components. The two sources are assumed to interact minimally, and therefore their energy momentum tensors are conserved…

General Relativity and Quantum Cosmology · Physics 2014-08-21 Suresh Kumar

In this paper, we have considered a quadratic variation of the deceleration parameter ($q$) as a function of cosmic time ($t$) which describes a smooth transition from the decelerating phase of the Universe to an accelerating one and also…

General Relativity and Quantum Cosmology · Physics 2022-06-30 Ritika Nagpal , Shibesh Kumar Jas Pacif

We study the evolution of the cosmological parameters, namely, the deceleration parameter $q(z)$ and the parameter of effective equation of state in a universe contains, besides the ordinary matter and dark energy, a self-interacting…

General Relativity and Quantum Cosmology · Physics 2015-11-04 E. H. Baffou , M. J. S. Houndjo , M. E. Rodrigues , A. V. Kpadonou , J. Tossa

Constraining the dark energy deceleration parameter is one of the fascinating topics in the recent cosmological paradigm. This work aims to reconstruct the dark energy using parametrization of the deceleration parameter in a flat FRW…

General Relativity and Quantum Cosmology · Physics 2023-09-26 Amine Bouali , Himanshu Chaudhary , Ujjal Debnath , Alok Sardar , G. Mustafa

We revisit the evolution of the scale factor in a flat FRW spacetime with a new generalized decay rule for the dynamic $\Lambda$-term under modified theories of gravity. It analyses certain cosmological parameters and examines their…

General Physics · Physics 2021-08-02 Anirudh Pradhan , De Avik , Tee How Loo , D. C. Maurya

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 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

We propose that the size of the universe and its rate of expansion cannot be simultaneously specified with arbitrary precision, a quantum mechanical statement encoded in a deformed commutation relation for the scale factor. The deformation…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-15 Savvas M. Koushiappas

We consider a cosmological model dominated by stiff fluid with a constant bulk viscosity. We classify all the possible cases of the universe predicted by the model and analyzing the scale factor, density as well as the curvature scalar. We…

General Relativity and Quantum Cosmology · Physics 2015-06-19 Titus K Mathew , Aswathy M B , Manoj M

Nojiri \& Odintsov \cite{noj1} and Hu \& Sawicki \cite{hu} have studied non-linear functions in modified gravity that explain the cosmic acceleration without cosmological constant, fulfil the conditions of local gravity \& stability and…

General Relativity and Quantum Cosmology · Physics 2019-08-14 Gauranga C Samanta , Nisha Godani

In this paper, a general FRW cosmological model has been constructed in $f(R,T)$ gravity reconstruction with variable cosmological constant. A number of solutions to the field equations has been generated by utilizing a form for the Hubble…

General Relativity and Quantum Cosmology · Physics 2018-10-17 Nasr Ahmed , Sultan Z. Alamri

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

The evolution of the dark energy parameter within the scope of a spatially homogeneous and isotropic Friedmann-Robertson-Walker (FRW) model filled with perfect fluid and dark energy components is studied by generalizing the recent results…

General Physics · Physics 2014-03-11 Anirudh Pradhan

A new class of exact solutions of Einstein's field equations with a perfect fluid source, variable gravitational coupling $G$ and cosmological term $\Lambda$ for FRW spacetime is obtained by considering variable deceleration parameter…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Anirudh Pradhan , Ajay Kumar Singh , Saeed Otarod

In this paper, we study the dynamical behaviour of the Universe in the $F(R,G)$ theory of gravity, where $R$ and $G$ respectively denote the Ricci scalar and Gauss-Bonnet invariant. Our wide analysis encompasses the energy conditions,…

General Relativity and Quantum Cosmology · Physics 2022-04-22 Santosh V. Lohakare , S. K. Tripathy , B. Mishra
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