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We present the first fully non-linear evolutions of binary neutron star mergers in a moving-punctures approach in Einstein-scalar-Gauss-Bonnet gravity. We study both linear and quadratic-type couplings between the scalar and the…

General Relativity and Quantum Cosmology · Physics 2026-02-12 Llibert Aresté Saló , Ricard Aguilera-Miret , Miguel Bezares , Thomas P. Sotiriou

In this work we explore the dynamical system phase space of Einstein-Gauss-Bonnet theory in the cosmological minisuperspace. This approach binds the main features of the theory through a system of autonomous differential equations, in the…

General Relativity and Quantum Cosmology · Physics 2022-11-14 Konstantinos F. Dialektopoulos , Jackson Levi Said , Zinovia Oikonomopoulou

The present work is focused on the investigation of the existence of compact structures describing anisotropic matter distributions within the framework of modified gravity theories, specifically f(R,$\mathcal{T}$) gravity theory.…

General Relativity and Quantum Cosmology · Physics 2019-08-14 S. K. Maurya , Abdelghani Errehymy , Debabrata Deb , Francisco Tello-Ortiz , Mohammed Daoud

We investigate irregularity factors for a self-gravitating spherical star evolving in the presence of imperfect fluid. We explore the gravitational field equations and the dynamical equations with the systematic construction in $f(R,T)$…

General Relativity and Quantum Cosmology · Physics 2016-06-29 Z. Yousaf , Kazuharu Bamba , M. Zaeem ul Haq Bhatti

We apply cosmological reconstruction methods to the $f(R,T)$ modified gravity, in its recently developed scalar-tensor representation. We do this analysis assuming a perfect fluid in a Friedmann-Lema\^{i}tre-Robsertson-Walker (FLRW)…

General Relativity and Quantum Cosmology · Physics 2024-07-24 Tiago B. Gonçalves , João Luís Rosa , Francisco S. N. Lobo

In this paper, model of charged gravastar under $f(T)$ modified gravity is obtained. The model has been explored by taking the diagonal tetrad field of static spacetime together with electric charge. To solve the Einstein-Maxwell field…

General Relativity and Quantum Cosmology · Physics 2021-06-18 Piyali Bhar , Pramit Rej

Cosmological scalar perturbation theory studied in the Newtonian gauge depends on two potentials $\Phi$ and $\Psi$. In General Relativity (GR) they must coincide ($\Phi=\Psi$) in the absence of anisotropic stresses sourced by the energy…

Cosmology and Nongalactic Astrophysics · Physics 2019-01-02 C. M. S. Barbosa , H. Velten , J. C. Fabris , Rudnei O. Ramos

In this thesis, I investigate how to construct a self-consistent model of deformed general relativity using canonical methods and metric variables. The specific deformation of general covariance is predicted by some studies into loop…

General Relativity and Quantum Cosmology · Physics 2019-10-07 Rhiannon Cuttell

The spectrum of oscillating compact objects can be considerably altered in alternative theories of gravity. In particular, it may be enriched by modes with no counterpart in general relativity, tied to the dynamics of additional degrees of…

General Relativity and Quantum Cosmology · Physics 2022-01-21 Raissa F. P. Mendes , Néstor Ortiz , Nikolaos Stergioulas

The energy density spectrum is an observable of gravitational waves. Divergence has appeared in the energy density spectra of the scalar induced gravitational waves for different gauge fixings. To resolve the discrepancy, we investigate the…

General Relativity and Quantum Cosmology · Physics 2020-10-06 Zhe Chang , Sai Wang , Qing-Hua Zhu

We study the behavior under conformal transformations of energy and other charges in generic scalar-tensor models. This enables us to conclude that the ADM/AD masses are invariant under field redefinitions mixing metric and scalar despite…

General Relativity and Quantum Cosmology · Physics 2009-11-11 S. Deser , Bayram Tekin

The understanding of stellar structure represents the crossroads of our theories of the nuclear force and the gravitational interaction under the most extreme conditions observably accessible. It provides a powerful probe of the strong…

General Relativity and Quantum Cosmology · Physics 2020-09-15 Gonzalo J. Olmo , Diego Rubiera-Garcia , Aneta Wojnar

We consider scalar-Gauss-Bonnet and modified Gauss-Bonnet gravities and reconstruct these theories from the universe expansion history. In particular, we are able to construct versions of those theories (with and without ordinary matter),…

High Energy Physics - Theory · Physics 2008-11-26 Guido Cognola , Emilio Elizalde , Shin'ichi Nojiri , Sergei D. Odintsov , Sergio Zerbini

In this paper, we assess different charged self-gravitating stellar models possessing anisotropic matter source in the background of $f(G,T)$ gravity. For this purpose, we choose a well-known model of this gravity, i.e., $f(G,T)=G^2+\varrho…

General Relativity and Quantum Cosmology · Physics 2023-12-01 M. Sharif , K. Hassan

This paper is devoted to investigate the recently introduced $f(\mathcal{G},\textit{T})$ theory of gravity, where $\mathcal{G}$ is the Gauss-Bonnet term, and ${\textit{T}}$ is the trace of the energy-momentum tensor. For this purpose,…

General Physics · Physics 2017-12-13 M. Farasat Shamir

A correspondence between fluctuations of non-minimally coupled scalar fields and that of an effective fluid with heat flux and anisotropic stresses, is shown. Though the correspondence between respective stress tensors of scalar fields and…

General Relativity and Quantum Cosmology · Physics 2022-05-18 Seema Satin

In this paper the scalar-tensor theory is applied to the study of perturbations in a multi-fluid universe, using the 1+3 covariant approach. Both scalar and harmonic decompositions are instituted on the perturbation equations. In…

General Relativity and Quantum Cosmology · Physics 2020-11-30 Joseph Ntahompagaze , Shambel Sahlu , Amare Abebe , Manasse R. Mbonye

In several classes of modified gravity theories, extra degrees of freedom are not completely screened in the interiors of stellar and substellar objects. In such theories, the hydrostatic equilibrium condition inside these objects is…

General Relativity and Quantum Cosmology · Physics 2023-10-27 Shaswata Chowdhury

This study explores the application of complexity factor within the context of Rastall gravity, exploring its implications on a static spacetime admitting spherical symmetry associated with anisotropic fluids under an electromagnetic field.…

General Relativity and Quantum Cosmology · Physics 2025-08-20 Tayyab Naseer

Teleparallel Gravity (TG) describes gravitation as a torsional- rather than curvature-based effect. As in curvature-based constructions of gravity, several different formulations can be proposed, one of which is the Teleparallel equivalent…

General Relativity and Quantum Cosmology · Physics 2020-07-01 Soumya Chakrabarti , Jackson Levi Said