English
Related papers

Related papers: Quasi Static Evolution of Compact Objects in Modif…

200 papers

We review recently offered notions of quasi-static evolution of the axial self-gravitating structures at large-scales and the criteria to characterize the corresponding evolutionary aspects under the influence of strong curvature regimes.…

General Relativity and Quantum Cosmology · Physics 2024-08-26 Z. Yousaf , Kazuharu Bamba , M. Z. Bhatti , U. Farwa

Relativistic scalar fields are ubiquitous in modified theories of gravity. An important tool in understanding their impact on structure formation, especially in the context of N-body simulations, is the quasi-static approximation in which…

Cosmology and Nongalactic Astrophysics · Physics 2014-02-05 Johannes Noller , Francesca von Braun-Bates , Pedro G. Ferreira

Numerical simulations in modified gravity have commonly been performed under the quasi-static approximation -- that is, by neglecting the effect of time derivatives in the equation of motion of the scalar field that governs the fifth force…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-26 Sownak Bose , Wojciech A. Hellwing , Baojiu Li

We study under what conditions the thermal peeling is present for dissipative local and quasi-local anisotropic spherical matter configurations. The thermal peeling occurs when different signs in the velocity of fluid elements appears,…

General Relativity and Quantum Cosmology · Physics 2014-06-24 L. Becerra , H. Hernandez , L. A. Nunez

We explore the evolutionary behaviors of compact objects in a modified gravitational theory with the help of structure scalars. Particularly, we consider the spherical geometry coupled with heat and radiation emitting shearing viscous…

General Relativity and Quantum Cosmology · Physics 2016-04-12 Z. Yousaf , Kazuharu Bamba , M. Zaeem ul Haq Bhatti

In the framework of $f\left(R, T, R_{ab}T^{ab}\right)$ gravity theory, the slow-roll approximation of the cosmic inflation is investigated, where $T$ is the trace of the energy-momentum tensor $T^{ab}$, $R$ and $R_{ab}$ are the Ricci scalar…

General Relativity and Quantum Cosmology · Physics 2024-11-01 Zhe Feng

We investigate classes of shear-free cosmological dust models with irrotational fluid flows within the framework of $f(T)$ gravity. In particular, we use the $1 + 3$ covariant formalism and present the covariant linearised evolution and…

General Relativity and Quantum Cosmology · Physics 2022-07-27 Heba Sami , Shambel Sahlu , Amare Abebe , Peter K. S. Dunsby

In this paper we investigate the inflationary dynamics of an $f(R)$ gravity in the presence of a canonical scalar field. We specifically choose the cosmological evolution to be a quasi-de Sitter evolution and also the $f(R)$ gravity is…

General Relativity and Quantum Cosmology · Physics 2018-08-01 K. Kleidis , V. K. Oikonomou

In this contribution, we consider the equivalence between $f(R)$ gravity and scalar-tensor theories to study the evolution of scalar cosmological perturbations in the $1 + 3$ covariant formalism for the classes of shear-free cosmological…

General Relativity and Quantum Cosmology · Physics 2021-09-22 Heba Sami , Amare Abebe

We discuss the gravitational collapse of spherical compact objects in the background of $f(R,T,Q)$ theory, where $R$ represent the Ricci scalar, $T$ is the trace of energy momentum tensor while $Q\equiv R_{\mu\nu}T^{\mu\nu}$, and…

General Relativity and Quantum Cosmology · Physics 2020-03-03 M. Z. Bhatti , Kazuharu Bamba , Z. Yousaf , M. Nawaz

This work is aimed to explore the dark dynamical effects of $f(R,T)$ modified gravity theory on the dynamics of compact celestial star. We have taken the interior geometry as spherical star which is filled with imperfect fluid distribution.…

General Relativity and Quantum Cosmology · Physics 2017-11-09 M. Z. Bhatti , Z. Yousaf , M. Ilyas

Planar sliding of objects is modeled and analyzed. The model can be used for non-prehensile manipulation of objects lying on a surface. We study possible motions generated by frictional contacts, such as those arising between a soft finger…

Robotics · Computer Science 2019-04-16 M. Mahdi Ghazaei Ardakani , Joao Bimbo , Domenico Prattichizzo

In this paper, we have analyzed the stability of cylindrically symmetric collapsing object filled with locally anisotropic fluid in $f(R,T)$ theory, where $R$ is the scalar curvature and $T$ is the trace of stress-energy tensor of matter.…

General Physics · Physics 2018-11-15 M. Zubair , Hina Azmat , Ifra Noureen

A semi--numerical approach proposed many years ago for describing gravitational collapse in the post--quasi--static approximation, is modified in order to avoid the numerical integration of the basic differential equations the approach is…

General Relativity and Quantum Cosmology · Physics 2024-03-13 L. Herrera , A. Di prisco , J. Ospino

Using a framework based on the $1+3$ formalism we carry out a study on axially and reflection symmetric dissipative fluids, in the quasi--static regime. We first derive a set of invariantly defined "velocities", which allow for an…

General Relativity and Quantum Cosmology · Physics 2016-03-08 L. Herrera , A. Di Prisco , J. Ospino , J. Carot

Theories of modified gravity, in both the linear and fully non-linear regime, are often studied under the assumption that the evolution of the new (often scalar) degree of freedom present in the theory is quasi-static. This approximation…

General Relativity and Quantum Cosmology · Physics 2015-09-09 Hans A. Winther , Pedro G. Ferreira

The main purpose of this paper is to investigates structure scalars in the context of $f(\mathcal{G}, T)$ gravity, where $\mathcal{G}$ is the Gauss-Bonnet invariant and $T$ is the trace of stress energy tensor. For this aim, we have…

General Relativity and Quantum Cosmology · Physics 2018-04-05 M. Farasat Shamir , M. Awais Sadiq

The Teleparallel Theory is equivalent to General Relativity, but whereas in the latter gravity has to do with curvature, in the former gravity is described by torsion. As is well known, there is in the literature a host of alternative…

General Relativity and Quantum Cosmology · Physics 2024-01-05 José C. N. de Araujo , Hemily G. M. Fortes

We present a sampling-based approach to reasoning about the caging-based manipulation of rigid and a simplified class of deformable 3D objects subject to energy constraints. Towards this end, we propose the notion of soft fixtures extending…

Robotics · Computer Science 2023-09-06 Yifei Dong , Florian T. Pokorny

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
‹ Prev 1 2 3 10 Next ›