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This paper analyzes the evolution of cavities for the cluster of stars in the context of modified Gauss-Bonnet gravity. For this purpose, we assume a spherically symmetric geometry with locally anisotropic fluid distribution. It is assumed…

General Relativity and Quantum Cosmology · Physics 2023-03-08 Rubab Manzoor , M. Awais Sadiq

We analyse how drag forces modify the orbits of objects moving through extended gaseous distributions. We consider how hydrodynamic (surface area) drag forces and dynamical friction (gravitational) drag forces drive the evolution of orbital…

Earth and Planetary Astrophysics · Physics 2022-05-13 Ákos Szölgyén , Morgan MacLeod , Abraham Loeb

We construct a time-dependent expression of the computational complexity of a quantum system which consists of two conformal complex scalar field theories in d dimensions coupled to constant electric potentials and defined on the boundaries…

High Energy Physics - Theory · Physics 2019-05-29 Musema Sinamuli , Robert B. Mann

The field equations of $f(R,\mathcal{G})$ gravity are rewritten in the form of obvious wave equations with the stress-energy pseudotensor of the matter fields and the gravitational field, as their sources, under the de Donder condition. The…

General Relativity and Quantum Cosmology · Physics 2019-12-04 Bofeng Wu , Chao-Guang Huang

The homogeneous and isotropic cosmological model in generalized $ f(R,T^\phi) $ theories associated with scalar field is discussed, which is motivated by the $ f(R,T) $ theory of gravity studied by Harko et al. \cite{Harko:2011kv,…

General Relativity and Quantum Cosmology · Physics 2022-12-27 J. K. Singh , Akanksha Singh , Shaily , J. Jena

Electrically charged systems bound by a strong gravitational force can sustain a huge amount of electric charge (up to 10^20C) against Coulomb repulsion. General relativistically such systems form a stable hydrostatic configuration both in…

General Relativity and Quantum Cosmology · Physics 2009-03-24 Babur M. Mirza

We investigate the propagation of gravitational waves in the context of fourth order gravity nonminimally coupled to a massive scalar field. Using the damping of the orbital period of coalescing stellar binary systems, we impose constraints…

General Relativity and Quantum Cosmology · Physics 2015-07-10 Gaetano Lambiase , Mairi Sakellariadou , Antonio Stabile , Arturo Stabile

Aspects of the dynamical glass transition are considered within a mean field spin glass model. At the dynamical transition the the system condenses in a state of lower entropy. The difference, the information entropy or complexity, is…

Condensed Matter · Physics 2007-05-23 Th. M. Nieuwenhuizen

For cosmologically interesting $f(R)$ gravity models, we derive the complete set of the linearized field equations in the Newtonian gauge, under environments of the solar system, galaxies and clusters respectively. Based on these equations,…

Astrophysics · Physics 2008-11-26 Pengjie Zhang

This work examines the cosmological implications of two functional forms of $f(R,T) = R + \alpha T^n$ gravity: for two different value of $n $ where $n=1$ and $n\neq 1$, and $\alpha$ and $n$ are free parameters. The modified Friedmann…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-24 Mustapha Lamaaoune

In this paper we consider a semitetrad covariant decomposition of spherically symmetric spacetimes and find a governing hyperbolic equation of the Gaussian curvature of two dimensional spherical shells, that emerges due to the…

General Relativity and Quantum Cosmology · Physics 2022-11-23 Sayuri Singh , Dharmanand Baboolal , Rituparno Goswami , Sunil D. Maharaj

We analyze the cosmological solutions of $f(T,B)$ gravity using dynamical system analysis where $T$ is the torsion scalar and $B$ be the boundary term scalar. In our work, we assume two specific cosmological models. For first model, we…

General Relativity and Quantum Cosmology · Physics 2023-04-26 Amit Samaddar , S. Surendra Singh

This thesis investigates compact astrophysical objects within modified theories of gravity, focusing on neutron stars and strange stars. The work studies their internal structure, equilibrium, and stability in gravitational frameworks based…

General Relativity and Quantum Cosmology · Physics 2026-05-26 Sneha Pradhan

The review is devoted to consideration of possible observational consequences of modified gravity theories, suggested for explanation of the contemporary accelerated expansion of the universe. The major attention is paid to F(R)-models. It…

General Relativity and Quantum Cosmology · Physics 2019-11-11 Elena Arbuzova

We investigate static cylindrical solutions within an extended theory of modified gravity. By incorporating various coupling functions through a straightforward boost symmetry approach, we establish the equations of motion in a…

General Relativity and Quantum Cosmology · Physics 2024-07-31 Davood Momeni , Phongpichit Channuie , Mudhahir Al-Ajmi

We investigate a f(R) modification of gravity that is exponential in the Ricci scalar R to explain cosmic acceleration. The steepness of this dependence provides extra freedom to satisfy solar system and other curvature regime constraints.…

Cosmology and Nongalactic Astrophysics · Physics 2010-01-07 Eric V. Linder

In the context of f(R) theories of gravity, we study the cosmological evolution of scalar perturbations by using a completely general procedure. We find that the exact fourth-order differential equation for the matter density perturbations…

Astrophysics · Physics 2015-05-13 A. de la Cruz-Dombriz , A. Dobado , A. L. Maroto

We study environment-dependent clustering using the marked correlation function applied to Hu-Sawicki $f(R)$ modified gravity simulations. This gravity theory enriches the structure formation by enhancing gravity in a scale-dependent form.…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-12 Joaquin Armijo , Lucas Da Costa

General relativity is highly successful in explaining a wide range of gravitational phenomena including the gravitational waves emitted by binary systems and the shadows cast by supermassive black holes. From a modern perspective the theory…

General Relativity and Quantum Cosmology · Physics 2024-07-26 Jesse Daas , Cristobal Laporte , Frank Saueressig , Tim van Dijk

Corrections to solar system gravity are derived for f(G) gravity theories, in which a function of the Gauss-Bonnet curvature term is added to the gravitational action. Their effects on Newton's law, as felt by the planets, and on the…

High Energy Physics - Theory · Physics 2008-01-30 Stephen C. Davis