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We generalize Einstein's Lagrangian in a non-polynomial (in R) way. The usual Lagrangian (linear in R) is the zero $\alpha'$ limit of our theory, where $\alpha'$ is a parameter that is interpreted as the inverse cosmological costant before…

High Energy Physics - Theory · Physics 2008-02-03 C. Gasparakis

Cosmological analysis of extended Jordan-Brans-Dicke (eJBD) gravity is presented in the Einstein metric frame in which gravitational interaction is readily understandable. Our formulation is the first systematic investigation of how to…

High Energy Physics - Phenomenology · Physics 2023-10-03 Kunio Kaneta , Kin-ya Oda , Motohiko Yoshimura

The extended Jordan-Brans-Dicke (eJBD) theory of gravity is constrained by a host of astrophysical and cosmological observations spanning a wide range of scales. The current cosmological constraints on the first post-Newtonian parameter in…

Cosmology and Nongalactic Astrophysics · Physics 2019-06-11 Mario Ballardini , Domenico Sapone , Caterina Umiltà , Fabio Finelli , Daniela Paoletti

Virtual transitions in a Casimir-like configuration are utilized to probe quantum aspects of four-dimensional Einstein-Gauss-Bonnet (4D EGB) gravity. This study employs a quantum optics-based approach, wherein an Unruh-DeWitt detector…

General Relativity and Quantum Cosmology · Physics 2025-06-04 Syed Masood

The existence of Traversable Wormhole (TW) in the 4D Einstein-Gauss-Bonnet (4D-EGB) gravity is explored with phenomenological Bose-Einstein Condensates (BEC) dark matter density profile. In the framework of 4D EGB gravity, which one obtains…

General Relativity and Quantum Cosmology · Physics 2025-12-04 Bibhash Das , Bikash Chandra Paul

A modified Einstein-Gauss-Bonnet gravity in four dimensions where the quadratic Gauss-Bonnet term is coupled to a scalar field is considered. The field equations of the model are obtained by variational methods by making use of the…

General Relativity and Quantum Cosmology · Physics 2016-08-30 Hatice Özer , Ahmet Baykal , Özgür Delice

The Einstein- Gauss- Bonnet (EGB) gravity is an important modification of the Einstein theory of gravity and, for many gravitational phenomena, the Gauss- Bonnet (GB) correction term leads to drastic differences. In this paper, we study…

General Relativity and Quantum Cosmology · Physics 2022-12-05 Ayan Chatterjee , Avirup Ghosh , Suresh Jaryal

This essay elucidates recent achievements of the "nongravitating vacuum energy" (NGVE) theory" which has the feature that a shift of the Lagrangian density by a constant does not affect dynamics. In the first order formalism, a constraint…

General Relativity and Quantum Cosmology · Physics 2009-10-31 E. I. Guendelman , A. B. Kaganovich

In this work we study the inflationary framework of Einstein-Gauss-Bonnet theories which produce a primordial gravitational wave speed that respects the constraint imposed by the GW170817 event, namely $\left| c_T^2 - 1 \right| < 6 \times…

General Relativity and Quantum Cosmology · Physics 2024-07-18 V. K. Oikonomou

It is known that Gauss-Bonnet terms in higher dimensional gravity can produce an effective cosmological constant. We add extra examples to this picture by presenting explicitly two branches of accelerating vacuum solutions to the…

General Relativity and Quantum Cosmology · Physics 2015-05-30 Liu Zhao , Kun Meng

We consider dark energy cosmology in a de Sitter universe filled with quantum conformal matter. Our model represents a Gauss-Bonnet model of gravity with contributions from quantum effects. To the General Relativity action an arbitrary…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Iver Brevik , John Quiroga Hurtado

In this work we study the properties of compact spheres made of a charged perfect fluid with a MIT bag model EoS for quark matter. Considering static spherically symmetric spacetime we derive the hydrostatic equilibrium equations in the…

General Relativity and Quantum Cosmology · Physics 2022-03-01 Juan M. Z. Pretel , Ayan Banerjee , Anirudh Pradhan

We use our resummed quantum gravity approach to Einstein's general theory of relativity in the context of the Planck scale cosmology formulation of Bonanno and Reuter to estimate the value of the cosmological constant as \rho_\Lambda…

High Energy Physics - Phenomenology · Physics 2014-09-05 B. F. L. Ward

We study the predictions for structure formation in an induced gravity dark energy model with a quartic potential. By developing a dedicated Einstein-Boltzmann code, we study self-consistently the dynamics of homogeneous cosmology and of…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-14 Caterina Umiltà , Mario Ballardini , Fabio Finelli , Daniela Paoletti

Dark energy cosmology is considered in a modified Gauss-Bonnet model of gravity with and without a scalar field. It is shown that these generalizations of General Relativity endow it with a very rich cosmological structure: it may naturally…

General Relativity and Quantum Cosmology · Physics 2015-05-18 Emilio Elizalde , Ratbay Myrzakulov , Valery V. Obukhov , Diego Sáez-Gómez

The subject of this paper is to investigate the weak regime covariant scalar-tensor-vector gravity (STVG) theory, known as the MOdified gravity (MOG) theory of gravity. First, we show that the MOG in the absence of scalar fields is…

General Relativity and Quantum Cosmology · Physics 2018-10-09 M. Khurshudyan , N. S. Mazhari , D. Momeni , R. Myrzakulov , M. Raza

In this paper, we analyze the viability of a vacuum Gauss-Bonnet cosmology by examining the dynamics of the homogeneous and anisotropic background in 4+1 dimensions. The trajectories of the system either originate from the standard…

High Energy Physics - Theory · Physics 2008-11-26 R. Chingangbam , M. Sami , P. V. Tretyakov , A. V. Toporensky

Einstenian cubic gravity (ECG) is a modified theory of gravity constructed with cubic contractions of the curvature tensor. This theory has the remarkable feature of having the same two propagating degrees of freedom of Einstein gravity…

General Relativity and Quantum Cosmology · Physics 2024-06-04 L. A. Lessa , R. V. Maluf , J. E. G. Silva , C. A. S. Almeida

We propose the generalized uncertainty principle (GUP) with an additional term of quadratic momentum motivated by string theory and black hole physics as a quantum mechanical framework for the minimal length uncertainty at the Planck scale.…

General Physics · Physics 2022-10-25 Abdel Magied Diab , Abdel Nasser Tawfik

Gravitational wave (GW) constraints have recently been used to significantly restrict models of dark energy and modified gravity. New bounds arising from GW decay and GW-induced dark energy instabilities are particularly powerful in this…

Cosmology and Nongalactic Astrophysics · Physics 2020-03-25 Johannes Noller
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