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In the framework of teleparallel gravity, the Friedman-Robertson-Walker cosmological model with scalar tensor theory where scalar field is non-minimally coupled to both the torsion scalar and boundary term is studied. Utilizing the Noether…

General Relativity and Quantum Cosmology · Physics 2018-08-29 Ganim Gecim , Yusuf Kucukakca

We investigate two simplified non-singular cyclic models with a negative time-varying cosmological constant to represent the non-conventional mechanism of negative cosmological constant expected to address the late-time cosmic acceleration.…

General Relativity and Quantum Cosmology · Physics 2026-05-21 Nasr Ahmed , Kazuharu Bamba

We investigate the cosmological dynamics induced by nonlinear electrodynamics in a homogeneous and isotropic universe, focusing on the role of primordial electromagnetic fields with random spatial orientations. Building upon a…

General Relativity and Quantum Cosmology · Physics 2025-10-15 Alan G. Cesar , Mario Novello , Eduardo Bittencourt , Fernando A. Franco

We investigate the geometrodynamical effects of introducing the boundary term in symmetric teleparallel gravity. Specifically, we consider a homogeneous and isotropic universe in $f\left( Q, B \right) $, where $Q$ is the non-metricity…

General Relativity and Quantum Cosmology · Physics 2023-09-27 Andronikos Paliathanasis

We propose that the size of the universe and its rate of expansion cannot be simultaneously specified with arbitrary precision, a quantum mechanical statement encoded in a deformed commutation relation for the scale factor. The deformation…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-15 Savvas M. Koushiappas

We present a special case of the Stephani solution with spherical symmetry while considering different values of spatial curvature. We investigate the dynamics of the universe evolution in our model, build the R--T-regions for the resulting…

General Relativity and Quantum Cosmology · Physics 2020-02-06 I. Bormotova , E. Kopteva , M. Churilova , Z. Stuchlik

We explore the cosmological evolution in the exponential gravity $f(R)=R +c_1 (1-e^{- c_2 R})$ ($c_{1, 2} = \mathrm{constant}$). We summarize various viability conditions and explicitly demonstrate that the late-time cosmic acceleration…

Cosmology and Nongalactic Astrophysics · Physics 2010-09-10 Kazuharu Bamba , Chao-Qiang Geng , Chung-Chi Lee

We perform a model-independent investigation of the thermodynamic evolution of the Universe by reconstructing the expansion history from observational data using Gaussian Process regression. We consider three independent combinations of…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-22 Afaq Maqsood , Tanima Duary

The main objective of this study is to investigate the phenomenon of the bouncing scenario of the universe. The most widely recognized cosmological framework is the standard cosmological model, sometimes referred to as the Big Bang model.…

General Relativity and Quantum Cosmology · Physics 2024-02-13 A. S. Agrawal

The prevailing cosmological model with the lambda-term, in which the space is flat, is studied (section 1). The corresponding age of the Universe (t0) is calculated (assuming a Hubble constant consistent with the measurements of the Hubble…

Astrophysics · Physics 2009-09-29 Evangelos Chaliasos

We explore the phase-space of a multiscalar-torsion gravitational theory within a cosmological framework characterized by a spatially flat Friedmann-Lema\^{\i}tre-Robertson-Walker model. Our investigation focuses on teleparallelism and…

General Relativity and Quantum Cosmology · Physics 2024-03-07 Genly Leon , Andronikos Paliathanasis , Alfredo D. Millano

The ghost-free theory of massive gravity with two dynamical metrics has been shown to produce viable cosmological expansion, where the late-time acceleration of the Universe is due to the finite range of the gravitational interaction rather…

Cosmology and Nongalactic Astrophysics · Physics 2014-10-29 Adam R. Solomon , Yashar Akrami , Tomi S. Koivisto

We have investigated the accelerating behaviour of the universe in $f(Q,T)$ gravity in an isotropic and homogeneous space-time. We have initially derive the dynamical parameters in the general form of $f(Q,T)=\alpha Q^{m}+\beta T$ [Xu et…

General Relativity and Quantum Cosmology · Physics 2023-05-31 Laxmipriya Pati , S. A. Narawade , S. K. Tripathy , B. Mishra

Recollapsing homogeneous and isotropic models present one of the key ingredients for cyclic scenarios. This is considered here within a quantum cosmological framework in presence of a free scalar field with, in turn, a negative cosmological…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Martin Bojowald , Reza Tavakol

We apply the teleparallelism condition to the Poincar\'{e} gauge theory of gravity. The resultant teleparallelized cosmology is completely equivalent to the Friedmann cosmology derived from Einstein's general theory of relativity. The…

General Relativity and Quantum Cosmology · Physics 2014-09-10 Wenjie Lu , Wolung Lee , Kin-Wang Ng

It has previously been shown that it is more general to describe the evolution of the universe based on the emergence of the space and the energy balance relation. Here we investigate the thermodynamic properties of the universe described…

General Relativity and Quantum Cosmology · Physics 2019-03-27 Fei-Quan Tu , Yi-Xin Chen , Qi-Hong Huang

We study a cosmological model in the framework of teleparallel gravity, where a vector field $A_\mu$ is non-minimally coupled to the torsion scalar $T$ in a flat Friedmann-Robertson-Walker (FRW) universe. Using the Noether symmetry…

General Relativity and Quantum Cosmology · Physics 2025-08-26 Yusuf Kucukakca , Fereshteh Omidvar , Amin Rezaei Akbarieh

In this paper we study the evolution of cosmological perturbations through a nonsingular bouncing universe using covariant perturbation theory and examine the validity of linear perturbation theory. The bounce is modeled by a two component…

General Relativity and Quantum Cosmology · Physics 2014-05-16 Atanu Kumar

We propose an Einstein-{\ae}ther scalar-tensor cosmological model. In particular in the scalar-tensor Action Integral we introduce the {\ae}ther field with {\ae}ther coefficients to be functions of the scalar field. This cosmological model…

General Relativity and Quantum Cosmology · Physics 2021-07-28 Andronikos Paliathanasis , Genly Leon

We generalize the spherical collapse model for the formation of bound objects to apply in a Universe with arbitrary positive cosmological constant. We calculate the critical condition for collapse of an overdense region and give exact…

Astrophysics · Physics 2007-05-23 Ewa L. Lokas , Yehuda Hoffman