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Related papers: Type IV singular bouncing cosmology from $f(T)$ Gr…

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The impact of topological terms that modify the Hilbert-Einstein action is here explored by virtue of a further $f(G)$ contribution. In particular, we investigate the phase-space stability and critical points of an equivalent scalar field…

General Relativity and Quantum Cosmology · Physics 2025-05-01 Giannis Papagiannopoulos , Orlando Luongo , Genly Leon , Andronikos Paliathanasis

We confront various nonsingular bouncing cosmologies with the recently released BICEP2 data and investigate the observational constraints on their parameter space. In particular, within the context of the effective field approach, we…

Cosmology and Nongalactic Astrophysics · Physics 2014-08-19 Yi-Fu Cai , Jerome Quintin , Emmanuel N. Saridakis , Edward Wilson-Ewing

We perform the dynamical system analysis of the Locally Rotationally Symmetric (LRS) Bianchi type-I cosmological model in f(T) gravity in the presence of energy interaction . A cosmologically viable form of $f(T)$ is chosen (where $T$ is…

General Relativity and Quantum Cosmology · Physics 2025-10-14 Shivangi Rathore , S. Surendra Singh

The present work analyzes the various conditions in which there can be a bouncing universe solution in f(R) gravity. In the article an interesting method, to analyze the bouncing FRW solutions in a spatially flat universe using f(R) gravity…

General Relativity and Quantum Cosmology · Physics 2014-12-09 Niladri Paul , Saikat Nil Chakrabarty , Kaushik Bhattacharya

This paper is devoted to investigate the exact solutions of Bianchi type $I$ spacetime in the context of $f(R,T)$ gravity [1], where $f(R,T)$ is an arbitrary function of Ricci scalar $R$ and trace of the energy momentum tensor $T$. For this…

General Relativity and Quantum Cosmology · Physics 2015-06-30 M. Farasat Shamir

In this paper, we have explored the field equations of $f(T,B)$ gravity and determined the dynamical parameters with the hyperbolic function of Hubble parameter. The accelerating behavior has been observed and the behavior of equation of…

General Relativity and Quantum Cosmology · Physics 2022-07-22 S. A. Kadam , B. Mishra , S. K. Tripathy

We investigate a bouncing cosmological model within the Weyl-type $f(Q)$ gravity framework, employing a power-law form of the non-metricity scalar $Q$. The model successfully resolves the initial singularity problem by demonstrating a…

General Relativity and Quantum Cosmology · Physics 2026-02-04 Rita Rani , G. K. Goswami , J. K. Singh , Sushant G. Ghosh , Sunil D Maharaj

In this study, we explore the cosmological evolution of the Universe in the framework of covariant $f(Q)$ gravity, with a coupling function that evolves dynamically in proportion to the Hubble parameter. Two specific forms of the function…

General Relativity and Quantum Cosmology · Physics 2026-04-29 S. A. Narawade , S. A. Kadam

A cubic correction of $f(T)$ gravity, where $T$ is the teleparallel scalar torsion, is considered to describe gravity in spatially flat Friedmann-Robertson-Walker model. A scale factor permitting departure from inflation era has been…

General Physics · Physics 2015-11-06 G. G. L. Nashed , W. El Hanafy

We analyze the common four types of the finite-time singularities using a generic framework of the phase portrait geometric approach. This technique requires that the Friedmann system to be written as a one dimensional autonomous system. We…

General Relativity and Quantum Cosmology · Physics 2017-11-07 W. El Hanafy , G. G. L. Nashed

In this work we consider the realization of a variant emergent Universe scenario in the context of $f(R)$ gravity. We use well-known reconstruction techniques existing in the literature, and we find the approximate form of the vacuum $f(R)$…

General Relativity and Quantum Cosmology · Physics 2024-03-18 V. K. Oikonomou , Gregory K. Kafanelis

We intend to study a new class of cosmological models in $f(R, T)$ modified theories of gravity, hence define the cosmological constant $\Lambda$ as a function of the trace of the stress energy-momentum-tensor $T$ and the Ricci scalar $R$,…

General Physics · Physics 2020-03-26 Safiqul Islam , Praveen Kumar , G. S. Khadekar , Tapas K Das

We investigate the realization of a nonsingular cosmological bounce in metric $f(R)$ gravity using a controlled exponential deformation of the Starobinsky $R^{2}$ model. Adopting a smooth Gaussian-type bouncing scale factor, we first…

General Relativity and Quantum Cosmology · Physics 2026-03-31 G. G. L. Nashed , A. Eid

We investigate in detail the implications of the constant-roll condition on the inflationary era of a scalar field coupled to a teleparallel $f(T)$ gravity. The resulting cosmological equations constitute a reconstruction technique which…

General Relativity and Quantum Cosmology · Physics 2018-07-17 A. Awad , W. El Hanafy , G. G. L. Nashed , S. D. Odintsov , V. K. Oikonomou

A non-singular bouncing cosmology is generically obtained in loop quantum cosmology due to non-perturbative quantum gravity effects. A similar picture can be achieved in standard general relativity in the presence of a scalar field with a…

General Relativity and Quantum Cosmology · Physics 2014-03-17 Yi-Fu Cai , Edward Wilson-Ewing

Cuscuton Gravity is characterized as a scalar field that can be added to general relativity without introducing any new dynamical degrees of freedom on a cosmological background. Yet, it modifies gravity such that spacetime singularities…

High Energy Physics - Theory · Physics 2025-05-19 Amir Dehghani , Ghazal Geshnizjani , Jerome Quintin

Modification of gravity due to the curvature dependent term in the gravitational baryogenesis scenario is considered. It is shown that this term leads to the fourth order differential equation of motion for the curvature scalar instead of…

General Relativity and Quantum Cosmology · Physics 2017-04-05 E. V. Arbuzova , A. D. Dolgov

We use observations related to the variation of fundamental constants, in order to impose constraints on the viable and most used $f(T)$ gravity models. In particular, for the fine-structure constant we use direct measurements obtained by…

General Relativity and Quantum Cosmology · Physics 2017-04-18 Rafael C. Nunes , Alexander Bonilla , Supriya Pan , Emmanuel N. Saridakis

We investigate a fourth order model of gravity, having a free length parameter, and no cosmological constant or dark energy. We consider cosmological evolution of a flat Friedmann universe in this model for the case that the length…

General Relativity and Quantum Cosmology · Physics 2015-10-14 Shreya Banerjee , Nilesh Jayswal , Tejinder P. Singh

In this paper we have investigated a bulk viscous universe in $f(R,T)$ gravity where $R$ and $T$ are the Ricci scalar and trace of energy momentum tensor respectively. We have obtained explicit solutions of field equations in modified…

General Physics · Physics 2020-03-03 Anil Kumar Yadav , Lokesh Kumar Sharma , B. K. Singh , P. K. Sahoo