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In this article we give a full description of the dynamics of the flat anisotropic (4+1)-dimensional cosmological model in the presence of both Gauss-Bonnet and Einstein contributions. This is the first complete description of this model…

General Relativity and Quantum Cosmology · Physics 2010-12-13 S. A. Pavluchenko

We explore some cosmological features of the newly suggested 4D Gauss-Bonnet gravity through two different models assuming a varying cosmological constant. Observational constraints, such as the cosmic transit and the flat curvature, have…

General Relativity and Quantum Cosmology · Physics 2023-03-15 Nasr Ahmed , Ajab A. Alfreedi , Alaa A. Alzulaibani

5-dimensional special relativity can be considered as the 5-dimensional extension of Carmeli's cosmological special relativity, as well as the flat specialization of 5-d brane world theory. To this framework we add a 5-dimensional perfect…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Gianluca Gemelli

In this paper, in an FLRW background and a perfect fluid equation of state, we explore the possibility of the realization of an emergent scenario in a 4D regularized extension of Einstein-Gauss-Bonnet gravity, with the field equations…

General Relativity and Quantum Cosmology · Physics 2024-06-12 Mrinnoy M. Gohain , Kalyan Bhuyan

We provide a detailed description for power--law scaling Friedmann-Robertson-Walker cosmological scenarios dominated by two interacting perfect fluid components during the expansion. As a consequence of the mutual interaction between the…

High Energy Physics - Theory · Physics 2008-11-26 Mauricio Cataldo , Patricio Mella , Paul Minning , Joel Saavedra

The matter creation model of Prigogine--G\'eh\'eniau--Gunzig--Nardone is revisited in terms of a redefined creation pressure which does not lead to irreversible adiabatic evolution at constant specific entropy. With the resulting freedom to…

General Relativity and Quantum Cosmology · Physics 2022-09-15 Rossen I. Ivanov , Emil M. Prodanov

The main objective of this manuscript is to investigate the bouncing cosmology in the background of $f(\mathcal{Q})$ gravity, where $\mathcal{Q}$ defines the non-metricity. For this purpose, we use the reconstruction approach and consider a…

General Relativity and Quantum Cosmology · Physics 2024-04-02 M. Sharif , M. Zeeshan Gul , Nusrat Fatima

We study the constraints coming from local causality requirement in various $2+1$ dimensional dynamical theories of gravity. In topologically massive gravity, with a single parity non-invariant massive degree of freedom, and in new massive…

High Energy Physics - Theory · Physics 2017-05-16 Jose D. Edelstein , Gaston Giribet , Carolina Gomez , Ercan Kilicarslan , Matias Leoni , Bayram Tekin

We investigate an exact solution that describes the embedding of the four-dimensional (4D) perfect fluid in a five-dimensional (5D) Einstein spacetime. The effective metric of the 4D perfect fluid as a hypersurface with induced matter is…

High Energy Physics - Theory · Physics 2008-11-26 Jie Ren , Xin-He Meng , Liu Zhao

Trace-free Einstein gravity, in the absence of matter fields and using the Friedmann-Robertson-Walker (FRW) metric, is solvable both classically and quantum mechanically. This is achieved by using the conformal time as the time variable and…

General Relativity and Quantum Cosmology · Physics 2025-06-06 Merced Montesinos , Abdel Pérez-Lorenzana , Jorge Meza , Diego Gonzalez

We present a Friedmann-Robertson-Walker quantum cosmological model in the presence of Chaplygin gas and perfect fluid for early and late time epoches. In this work, we consider perfect fluid as an effective potential and apply Schutz's…

General Relativity and Quantum Cosmology · Physics 2008-11-26 P. Pedram , S. Jalalzadeh

We consider a theory of modified gravity possessing d extra spatial dimensions with a maximally symmetric metric and a scale factor, whose (4+d)-dimensional gravitational action contains terms proportional to quadratic curvature scalars.…

General Relativity and Quantum Cosmology · Physics 2018-09-05 Carsten van de Bruck , Chris Longden

This article deals with a nonrelativistic cosmological model based on Galilean covariance, formulated within a five-dimensional Galilean manifold. Within this framework, we construct an isotropic and homogeneous metric analogous to the…

General Relativity and Quantum Cosmology · Physics 2025-11-17 R. G. G. Amorim , A. F. Santos , K. V. S. Araújo , S. C. Ulhoa

Dynamical systems methods are used to investigate global behavior of the spatially flat Friedmann-Robertson-Walker cosmological model in gravitational theory with a non-minimally coupled scalar field and a constant potential function. We…

General Relativity and Quantum Cosmology · Physics 2015-11-11 Orest Hrycyna , Marek Szydlowski

We discuss a new extended gravity model in ordinary $D=4$ spacetime dimensions, where an additional term in the action involving Gauss-Bonnet topological density is included without the need to couple it to matter fields unlike the case of…

General Relativity and Quantum Cosmology · Physics 2018-11-13 Eduardo Guendelman , Emil Nissimov , Svetlana Pacheva

We construct models of static spherical distributions of perfect fluid in trace--free Einstein gravity theory. The equations governing the gravitational field are equivalent to the standard Einstein's equations however, their presentation…

General Relativity and Quantum Cosmology · Physics 2017-08-23 Sudan Hansraj , Rituparno Goswami , George Ellis , Njabulo Mkhize

This talk gives an overview of the recently-formulated Fluid/Gravity correspondence, which was developed in the context of gauge/gravity duality. Mathematically, it posits that Einstein's equations (with negative cosmological constant) in…

General Relativity and Quantum Cosmology · Physics 2011-07-19 Veronika E. Hubeny

The present work deals with cosmological solutions in $f(R,T)$ gravity theory for perfect fluid with constant equation of state ($\omega$). For a viable cosmological solution $\omega$ is restricted to $\omega<\dfrac{1}{3}$. Also depending…

General Relativity and Quantum Cosmology · Physics 2022-09-07 Akash Bose , Gopal Sardar , Subenoy Chakraborty

Motivated by recent evidence indicating that Quantum Einstein Gravity (QEG) might be nonperturbatively renormalizable, the exact renormalization group equation of QEG is evaluated in a truncation of theory space which generalizes the…

High Energy Physics - Theory · Physics 2008-11-26 O. Lauscher , M. Reuter

The evolution of spatially homogeneous and isotropic cosmological models containing a perfect fluid with equation of state p=w\rho\ and a cosmological constant \Lambda\ is investigated for arbitrary combinations of w and \Lambda, using…

Physics Education · Physics 2012-09-19 Sebastiano Sonego , Vittorino Talamini