Related references
Note: Only part of the references are listed.
Article
Physics, Multidisciplinary
Uday Chand De et al.
Summary: This study demonstrates for the first time that a quasi-conformally flat perfect fluid spacetime is both a de-Sitter spacetime and a Robertson-Walker spacetime, considering it as a solution of f(R, G)-gravity theory. The relationship among snap, jerk, and deceleration parameters is obtained using the flat Friedmann-Robertson-Walker metric. Several energy conditions are investigated with different models of f(R, G), and it is found that the weak, null, and dominant energy conditions are satisfied while the strong energy condition is violated, consistent with recent observational studies indicating the accelerating expansion of the current Universe.
EUROPEAN PHYSICAL JOURNAL PLUS
(2023)
Article
Physics, Multidisciplinary
Anirudh Pradhan et al.
Summary: We have developed a Bianchi I cosmological model in f (R, T) gravity theory that matches well with the current acceleration of the universe. The model shows a transition from deceleration in the past to acceleration at present. We have defined three energy parameters, Omega(m), Omega(mu), and Omega(sigma), where Omega(mu) is dominant. We used observational data sets to estimate various parameters and calculated the pressures, densities, and the age of the universe.
EUROPEAN PHYSICAL JOURNAL PLUS
(2023)
Article
Physics, Multidisciplinary
Uday Chand De et al.
Summary: The main objective of this paper is to investigate spacetimes that admit concircular curvature tensor in f(R) gravity theory. Firstly, concircularly flat and concircularly flat perfect fluid spacetimes in f R gravity are studied, obtaining the expressions of the isotropic pressure and the energy density. Next, some energy conditions are considered. Finally, perfect fluid spacetimes with divergence free concircular curvature tensor in f(R) gravity are studied, and several results are obtained.
FRONTIERS IN PHYSICS
(2022)
Article
Physics, Mathematical
Uday Chand De et al.
Summary: The article provides sufficient conditions for a pseudoprojective symmetric spacetime with Ricci tensor of Codazzi type to be either a perfect fluid or Einstein spacetime. It is also shown that a pseudoprojective symmetric spacetime is Einstein if its Ricci tensor is cyclic parallel. Additionally, the article investigates the properties of conformally flat pseudoprojective symmetric spacetimes and conformally flat perfect fluids in the f (R, G) theory of gravity, obtaining various results including the constancy of isotropic pressure and energy density in conformally flat perfect fluid spacetimes.
ADVANCES IN MATHEMATICAL PHYSICS
(2022)
Article
Mathematics, Applied
Santu Dey et al.
Summary: In this article, we investigate the properties and implementation of an eta-Ricci-Bourguignon soliton in general relativistic spacetime. We also explore the curvature conditions that allow for the existence of such solitons. Additionally, we examine the connection between the soliton and physical phenomena involving dust fluid, dark fluid, and the radiation era in the spacetime. Lastly, we describe the harmonic feature of eta-Ricci-Bourguignon solitons on a general relativistic spacetime.
JOURNAL OF GEOMETRY AND PHYSICS
(2022)
Article
Astronomy & Astrophysics
Santosh V. Lohakare et al.
Summary: In this paper, the bouncing behavior of cosmological models in the background of the Hubble function in the F(R,G) theory of gravity was studied. It was found that both models satisfy the bouncing cosmological properties and exhibit accelerating behavior at the late evolution time. The results of this study are of great significance for understanding cosmic evolution and solving cosmological problems.
Article
Astronomy & Astrophysics
Mahroz Javed et al.
Summary: This paper reviews anisotropic stellar spheres within the framework of modified f (R, G) gravity, formulating motion equations and evaluating dynamical equations based on anisotropic matter distribution and metric potentials. The credibility of the presented model is confirmed through the observation of physical aspects, showing freedom from singularities and physical stability in the system.
Article
Physics, Multidisciplinary
Avik De et al.
Summary: The study examines a 4-dimensional conformally flat generalized Ricci recurrent spacetime as a solution of f(R,G)-gravity theory, showing that additional terms from the modification of the gravitational sector can be expressed as a perfect fluid. Energy conditions are investigated for two models, indicating satisfaction of weak, null, and dominant energy conditions while violation of the strong energy condition, in agreement with recent observational studies on the accelerating universe.
FORTSCHRITTE DER PHYSIK-PROGRESS OF PHYSICS
(2021)
Article
Physics, Mathematical
K.K. Baishya et al.
REPORTS ON MATHEMATICAL PHYSICS
(2021)
Article
Physics, Mathematical
G. Navo et al.
INTERNATIONAL JOURNAL OF GEOMETRIC METHODS IN MODERN PHYSICS
(2020)
Article
Astronomy & Astrophysics
M. Z. Bhatti et al.
PHYSICS OF THE DARK UNIVERSE
(2020)
Review
Physics, Multidisciplinary
S. Nojiri et al.
PHYSICS REPORTS-REVIEW SECTION OF PHYSICS LETTERS
(2017)
Article
Astronomy & Astrophysics
Mariafelicia De Laurentis et al.
Article
Astronomy & Astrophysics
K. Atazadeh et al.
GENERAL RELATIVITY AND GRAVITATION
(2014)
Article
Physics, Mathematical
Sahanous Mallick et al.
INTERNATIONAL JOURNAL OF GEOMETRIC METHODS IN MODERN PHYSICS
(2014)
Article
Mathematics
Absos Ali Shaikh et al.
JOURNAL OF GEOMETRY
(2014)
Article
Astronomy & Astrophysics
Alvaro de la Cruz-Dombriz et al.
CLASSICAL AND QUANTUM GRAVITY
(2012)
Review
Physics, Multidisciplinary
Shin'ichi Nojiri et al.
PHYSICS REPORTS-REVIEW SECTION OF PHYSICS LETTERS
(2011)
Article
Mathematics
Fusun Ozen Zengin
MISKOLC MATHEMATICAL NOTES
(2011)
Article
Astronomy & Astrophysics
S. Capozziello et al.
CLASSICAL AND QUANTUM GRAVITY
(2008)
Article
Physics, Mathematical
Shin'ichi Nojiri et al.
INTERNATIONAL JOURNAL OF GEOMETRIC METHODS IN MODERN PHYSICS
(2007)