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We investigate the quantum cosmology of a closed spatially homogeneous and isotropic Friedmann-Lema\^itre-Robertson-Walker (FLRW) minisuperspace model with electromagnetic radiation as matter content. We solve the corresponding…

General Relativity and Quantum Cosmology · Physics 2022-07-15 S. Jalalzadeh

Analytical computations in relativistic cosmology can be split into two sets: time evolution relating the initial conditions to the observer's light-cone and light propagation to obtain observables. Cosmological perturbation theory in the…

General Relativity and Quantum Cosmology · Physics 2021-01-18 Ermis Mitsou , Giuseppe Fanizza , Nastassia Grimm , Jaiyul Yoo

The Hamilton-Jacobi analysis is applied to the dynamics of the scalar fluctuations about the Friedmann-Robertson-Walker (FRW). The gauge conditions are found from the consistency conditions. The physical degrees of freedom of the model are…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Dumitru Baleanu

I summarize the successes and failures of the most popular current cosmological models in accounting for the available observations. This evaluation, presented as the summary of the 11th Potsdam Workshop on Large-Scale Structure, was…

Astrophysics · Physics 2007-05-23 Neta A. Bahcall

We construct exact solutions representing a Friedmann-Lema\^itre-Robsertson-Walker (FLRW) universe in a generalized hybrid metric-Palatini theory. By writing the gravitational action in a scalar-tensor representation, the new solutions are…

General Relativity and Quantum Cosmology · Physics 2017-07-18 João L. Rosa , Sante Carloni , José P. S. Lemos , Francisco S. N. Lobo

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

Recent measurements using catalogues of quasars and radio galaxies have shown that the dipole anisotropy in the large-scale distribution of matter is about twice as large as is expected in the standard $\Lambda$CDM model, indeed in any…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-15 Sebastian von Hausegger

We present an exact analytical solution of the Einstein equations with cosmological constant in a spatially flat Robertson-Walker metric. This is interpreted as an isotropic Lemaitre-type version of the cosmological Friedmann model.…

General Relativity and Quantum Cosmology · Physics 2016-08-31 Ion I. Cotaescu , Dumitru N. Vulcanov

We study flat Friedmann-Lemaitre-Robertson-Walker cosmological models for a scalar field coupled nonminimally to teleparallel gravity with generic coupling and potential functions. The goal of this paper is to determine the conditions under…

General Relativity and Quantum Cosmology · Physics 2016-08-08 Laur Jarv , Alexey Toporensky

A review on spatially flat D-dimensional Friedmann-Robertson-Walker (FRW) model of the universe has been performed. Some standard parameterizations of the equation of state parameter of the Dark Energy models are proposed and the…

General Relativity and Quantum Cosmology · Physics 2019-03-26 Tanwi Bandyopadhyay , Ujjal Debnath

One of the outstanding problems in general relativistic cosmology is that of the averaging. That is, how the lumpy universe that we observe at small scales averages out to a smooth Friedmann-Lemaitre-Robertson-Walker (FLRW) model. The root…

Cosmology and Nongalactic Astrophysics · Physics 2016-11-21 Tharake Wijenayake , Weikang Lin , Mustapha Ishak

On small scales the observable Universe is highly inhomogeneous, with galaxies and clusters forming a complex web of voids and filaments. The optical properties of such configurations can be quite different from the perfectly smooth…

Cosmology and Nongalactic Astrophysics · Physics 2017-07-19 Viraj A. A. Sanghai , Pierre Fleury , Timothy Clifton

A late epoch cosmic acceleration may be naturally entangled with cosmic coincidence -- the observation that at the onset of acceleration the vacuum energy density fraction nearly coincides with the matter density fraction. In this Letter we…

Cosmology and Nongalactic Astrophysics · Physics 2014-10-07 Ciaran Doolin , Ishwaree P. Neupane

We consider the k=1 Friedman-Lemaitre-Robertson-Walker (FLRW) model within loop quantum cosmology (LQC), from the perspective of the two available quantization prescriptions. We focus our attention on the existence of the so called `inverse…

General Relativity and Quantum Cosmology · Physics 2016-04-28 Alejandro Corichi , Asieh Karami

Using the dynamical system theory we show that the Friedmann-Robertson-Walker (FRW) cosmological model with bulk viscous fluid in the presence of cosmological constant is equivalent to a degenerate two dimensional Bogdanov-Takens normal…

General Relativity and Quantum Cosmology · Physics 2020-10-19 Asmaa Abdel Azim , Adel Awad , E. I. Lashin

The present paper deals with the dynamics of spatially flat Friedmann-Lemaitre-Robertson-Walker (FLRW) cosmological model with a time varying cosmological constant $\Lambda$ where $\Lambda$ evolves with the cosmic time (t) through the…

General Relativity and Quantum Cosmology · Physics 2022-10-19 Chingtham Sonia , S. Surendra Singh

The $f(R)$ theory of gravitation developed perturbatively around the general theory of relativity with cosmological constant (the \text{$\Lambda$}CDM model) in a flat FLWR geometry is considered. As a result, a general explicit cosmological…

General Relativity and Quantum Cosmology · Physics 2025-02-25 Pham Van Ky , Nguyen Thi Hong Van , Nguyen Anh Ky

In this study of the modified $f(Q)$ theory of gravity in the spatially flat Friedmann-Lema\^itre-Robertson-Walker (FLRW) spacetime, we explore all the affine connections compatible with the symmetric teleparallel structure; three classes…

General Relativity and Quantum Cosmology · Physics 2024-10-25 Ganesh Subramaniam , Avik De , Tee-How Loo , Yong Kheng Goh

We describe the ``deflationary'' evolution from an initial de Sitter phase to a subsequent Friedmann-Lema\^{\i}tre-Robertson-Walker (FLRW) period as a specific non-equilibrium configuration of a self-interacting gas. The transition dynamics…

General Relativity and Quantum Cosmology · Physics 2015-06-25 Winfried Zimdahl , Alexander B. Balakin

This research article presents a new cosmological model formulated within the $f(R,G,T)$ framework, focusing on the observational signatures and parameter constraints of the model. The Markov Chain Monte Carlo (MCMC) technique is employed…

General Relativity and Quantum Cosmology · Physics 2026-05-26 Himanshu Chaudhary , Amine Bouali , Niyaz Uddin Molla , Ujjal Debnath , G. Mustafa
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