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Related papers: Configurational entropy in $f(T)$ gravity

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We show that the equations of motion governing the evolution of a collisionless gravitating system of particles in an expanding universe can be cast in a form which is almost independent of the cosmological density parameter, $\Omega$, and…

Astrophysics · Physics 2020-11-25 Adi Nusser , Jörg M. Colberg

We examine flat models containing a dark matter component and an arbitrary dark energy component, subject only to the constraint that the dark energy satisfies the weak energy condition. We determine the constraints that these conditions…

Astrophysics · Physics 2008-11-26 A. A. Sen , Robert J. Scherrer

The evolution of the Hubble parameter $H(z)$ with redshift $z$ is estimated from the Pantheon+ data of Type Ia supernovae, for the $\Lambda$CDM model and the three special cases of the eternal coasting (EC) cosmological model with three…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-23 Ardra Edathandel Sasi , Moncy Vilavinal John

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

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

The paper presents late time cosmology in $f(Q,T)$ gravity where the dark energy is purely geometric in nature. We start by employing a well motivated $f(Q,T)$ gravity model, $f(Q,T)=mQ^{n}+bT$ where $m,n$ and $b$ are model parameters.…

General Relativity and Quantum Cosmology · Physics 2020-07-06 Simran Arora , S. K. J. Pacif , Snehasish Bhattacharjee , P. K. Sahoo

We consider the cosmological evolution of a flat anisotropic Universe in $f(T)$ gravity in the presence of a perfect fluid. It is shown that the matter content of the Universe has a significant impact of the nature of a cosmological…

General Relativity and Quantum Cosmology · Physics 2021-06-10 Maria A. Skugoreva , Alexey V. Toporensky

We examine the evolution of the Friedmann Universe within our recent model of space-time identified with an elastic continuous medium whose deformations are described by a vector field constrained to obey a generalized four-dimensional…

General Relativity and Quantum Cosmology · Physics 2015-12-22 Fayçal Hammad

The Hubble parameter is a critical measurement in cosmology, which contains the most direct information of the cosmic expansion history. Since discrepancy is found between low redshift and high redshift estimations of Hubble constant, we…

Cosmology and Nongalactic Astrophysics · Physics 2014-10-02 Jiaxin Wang , Xinhe Meng

We have studied bulk viscosity in the modified $f(Q, T)$ gravity theory formalism, where $Q$ represents the non-metricity and $T$ denotes the trace of energy-momentum tensor within a flat Friedmann-Lema\^{i}tre-Robertson-Walker metric…

General Relativity and Quantum Cosmology · Physics 2021-12-01 Simran Arora , S. K. J. Pacif , Abhishek Parida , P. K. Sahoo

We investigate the thermodynamical and causal consistency of cosmological models of the cubic Quasi-Topological Gravity (QTG) in four dimensions, as well as their phenomenological consequences. Specific restrictions on the maximal values of…

General Relativity and Quantum Cosmology · Physics 2013-04-16 U. Camara dS , A. A. Lima , G. M. Sotkov

We investigate the properties of the FLRW flat cosmological models in which the vacuum energy density evolves with time, $\Lambda(t)$. Using different versions of the $\Lambda(t)$ model, namely quantum field vacuum, power series vacuum and…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 S. Basilakos , M. Plionis , J. Sola

We study the equation of state for dark energy and explicitly demonstrate that the future crossings of the phantom divide line $w_{\mathrm{DE}}=-1$ are the generic feature in the existing viable $f(R)$ gravity models. We also explore the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Kazuharu Bamba , Chao-Qiang Geng , Chung-Chi Lee

We investigate the late-time cosmic acceleration within the framework of viscous $f(T,L_m)$ gravity, where the gravitational action depends on both the torsion scalar $T$ and the matter Lagrangian $L_m$. In this context, the Universe is…

General Physics · Physics 2026-03-24 M. Koussour , Alnadhief H. A. Alfedeel , S. Muminov , J. Rayimbaev

In a thermodynamical model of cosmological FLRW event horizons for the dark energy (DE), we consider a logarithmic corrective term in the entropy to which corresponds a new term in the DE density. This model of $\Lambda (t)$ in an…

Astrophysics · Physics 2016-08-15 Cécile Barbachoux , Jérome Gariel , Gérard Le Denmat

In this note, we investigate the stability of the dark energy model from time crystals proposed in [1]. We emphasize two ingredients, the coupling of the scalar field to gravity, and the fact that these time crystals are on an expanding FRW…

General Relativity and Quantum Cosmology · Physics 2025-08-27 Laura Mersini-Houghton

We investigate infrared dynamics of four-dimensional Einstein gravity in de Sitter space. We set up a general framework to investigate dynamical scaling relations in quantum/classical gravitational theories. The conformal mode dependence of…

High Energy Physics - Theory · Physics 2020-02-25 Hiroyuki Kitamoto , Yoshihisa Kitazawa , Takahiko Matsubara

We investigate the evolution of gravitational waves through discontinuous evolution (transition) of the Hubble expansion rate $H(z)$ at a sudden cosmological singularity, which may be due to a transition of the value of the gravitational…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-04 Evangelos Achilleas Paraskevas , Leandros Perivolaropoulos

It is known that the unregularized expressions for the stress-energy tensor components corresponding to subhorizon and superhorizon vacuum fluctuations of a massless scalar field in a Friedmann-Robertson-Walker background are characterized…

General Relativity and Quantum Cosmology · Physics 2010-11-19 Ali Kaya

We propose a new five-parameter entropy function that proves to be singular-free during the entire cosmic evolution of the universe, and at the same time, also generalizes the Tsallis, Barrow, R\'{e}nyi, Sharma-Mittal, Kaniadakis and Loop…

General Relativity and Quantum Cosmology · Physics 2022-12-13 Sergei D. Odintsov , Tanmoy Paul
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