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

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In this paper, we have investigated the role of different fluid parameters particularly electromagnetic field and $f(R)$ corrections on the evolution of cylindrical compact object. We have explored the modified field equations, kinematical…

General Physics · Physics 2016-12-08 Z. Yousaf , M. Zaeem-ul-Haq Bhatti

Two quasi-linear approximations, the frozen flow approximation (FFA) and the frozen potential approximation (FPA), have been proposed recently for studying the evolution of a collisionless self-gravitating fluid. In the FFA it is assumed…

Astrophysics · Physics 2015-06-24 F. Bernardeau , T. P. Singh , B. Banerjee , S. M. Chitre

In this paper we study scalar perturbations of the metric for nonlinear $f(R)$ models. We consider the Universe at the late stage of its evolution and deep inside the cell of uniformity. We investigate the astrophysical approach in the case…

Cosmology and Nongalactic Astrophysics · Physics 2014-09-04 Maxim Eingorn , Jan Novák , Alexander Zhuk

In the context of $f(R)$ theories of gravity, we study the evolution of scalar cosmological perturbations in the metric formalism. Using a completely general procedure, we find the exact fourth-order differential equation for the matter…

Astrophysics · Physics 2008-11-26 A. de la Cruz-Dombriz , A. Dobado , A. L. Maroto

Quasistatic evolutions of critical points of time-dependent energies exhibit piecewise smooth behavior, making them useful for modeling continuum mechanics phenomena like elastic-plasticity and fracture. Traditionally, such evolutions have…

Optimization and Control · Mathematics 2026-01-09 Stefano Almi , Massimo Fornasier , Jona Klemenc , Alessandro Scagliotti

In this work we investigate several theoretical and phenomenological implications of a scalar -$F(R)$ gravity containing a non-minimal coupling to the scalar curvature. This kind of model is a generalization of axion-$F(R)$ gravity models,…

General Relativity and Quantum Cosmology · Physics 2020-05-20 Shin'ichi Nojiri , S. D. Odintsov , V. K. Oikonomou

$f(R)$ gravity is one of the simplest theories of modified gravity to explain the accelerated cosmic expansion. Although it is usually assumed that the quasi-Newtonian approach (a combination of the quasi-static approximation and sub-Hubble…

General Relativity and Quantum Cosmology · Physics 2015-12-02 Mu-Chen Chiu , Andy Taylor , Chenggang Shu , Hong Tu

The present paper is devoted to investigate the possible emergence of relativistic compact stellar objects through modified $f(R,T)$ gravity. For anisotropic matter distribution, we used Krori and Barura solutions and two notable and viable…

General Physics · Physics 2018-05-29 Z. Yousaf , M. Zaeem-ul-Haq Bhatti , M. Ilyas

We establish a well-posedness theory for the f(R) theory of modified gravity, which is a generalization of Einstein's theory of gravitation. The scalar curvature R of the spacetime, which arises in the integrand of the Einstein-Hilbert…

Analysis of PDEs · Mathematics 2014-12-30 Philippe G. LeFloch , Yue Ma

We obtain a class of anisotropic spherically symmetric relativistic solutions of compact objects in hydrostatic equilibrium in the $f(R,T) =R+2\chi T$ modified gravity, where $R$ is the Ricci scalar, $T$ is the trace of the energy momentum…

General Physics · Physics 2020-09-18 S. Dey , A. Chanda , B. C. Paul

At its core, hydrodynamics is a many-body low-energy effective theory for the long-wavelength, long-timescale dynamics of conserved charges in systems close to thermodynamic equilibrium. It has a wide range of applications spanning from…

High Energy Physics - Theory · Physics 2024-08-22 Luca Martinoia

We study a relaxed formulation of the quasistatic evolution problem in the context of small strain associative elastoplasticity with softening. The relaxation takes place in spaces of generalized Young measures. The notion of solution is…

Analysis of PDEs · Mathematics 2007-05-23 Gianni Dal Maso , Antonio DeSimone , Maria Giovanna Mora , Massimiliano Morini

Several extensions of General Relativity and high energy physics include scalar fields as extra degrees of freedom. In the search for predictions in the non-linear regime of cosmological evolution, the community makes use of numerical…

Cosmology and Nongalactic Astrophysics · Physics 2014-09-04 Claudio Llinares , David Mota

We consider the familiar problem of a minimally coupled scalar field with quadratic potential in flat Friedmann-Lema\^itre-Robertson-Walker cosmology to illustrate a number of techniques and tools, which can be applied to a wide range of…

General Relativity and Quantum Cosmology · Physics 2015-06-19 Artur Alho , Claes Uggla

We examine the accuracy of the quasi-static approximation and a parametric form commonly employed for evolving linear perturbations in f(R) gravity theories and placing cosmological constraints. In particular, we analyze the nature and the…

Cosmology and Nongalactic Astrophysics · Physics 2012-12-13 Alireza Hojjati , Levon Pogosian , Alessandra Silvestri , Starla Talbot

The present work is to introduce a new kind of modified gravitational theory, named as $f(\mathcal{R,G,T})$ (also $f(\mathcal{R,T,G})$) gravity, where $\mathcal{R}$ is the Ricci scalar, $\mathcal{G}$ is Gauss-Bonnet invariant and…

General Relativity and Quantum Cosmology · Physics 2021-11-16 M. Ilyas

This paper is devoted to the study of stellar evolution of compact objects whose energy density and pressure of the fluid are interlinked by means of MIT bag model and a realistic polytropic equation of state in the scenario of $f(R,T,Q)$…

General Relativity and Quantum Cosmology · Physics 2019-04-15 M. Sharif , Arfa Waseem

We consider load controlled quasistatic evolution. Well posedness results for the nonlocal continuum model related to peridynamics are established. We show local existence and uniqueness of quasistatic evolution for load paths originating…

Analysis of PDEs · Mathematics 2023-01-04 Debdeep Bhattacharya , Robert P. Lipton

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

We apply the post-quasi--static approximation, an iterative method for the evolution of self-gravitating spheres of matter, to study the evolution of anisotropic non-adiabatic radiating and dissipative distributions in General Relativity.…

General Relativity and Quantum Cosmology · Physics 2010-05-25 C. Peralta , L. Rosales , B. Rodrí guez-Mueller , W. Barreto