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相关论文: Barotropic FRW cosmologies with a Dirac-like param…

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In this study, we present constraints on the parameters of three well-known $f(R)$ gravity models, viz. (i) Hu-Sawicki, (ii) Starobinsky, and (iii) ArcTanh by using a joint analysis of recent cosmological observations. We perform analytical…

宇宙学与河外天体物理 · 物理学 2025-06-30 Darshan Kumar , Praveen Kumar Dhankar , Saibal Ray , Fengge Zhang

In this paper, we explore power law solution of FLRW universe model that is associated with a variable cosmological term $\Lambda(t)$ as a linear function of $\frac{\ddot{a}}{a}, (\frac{\dot{a}}{a})^2$ and $\rho$. The model parameters were…

综合物理 · 物理学 2025-04-28 G. K. Goswami , Anirudh Pradhan

Thermodynamics on the horizon of a flat universe at late times is studied in holographic cosmological models that assume an associated entropy on the horizon. In such models, a $\Lambda(t)$ model similar to a time-varying $\Lambda(t)$…

广义相对论与量子宇宙学 · 物理学 2020-01-01 Nobuyoshi Komatsu

We study the scenario of Kanadiakis horizon entropy cosmology which arises from the application of the gravity-thermodynamics conjecture using the Kaniadakis modified entropy. The resulting modified Friedmann equations contain extra terms…

Thermodynamics on the cosmological apparent horizon of a flat Friedmann-Lemaitre-Robertson-Walker metric has been investigated with Bekenstein entropy and Hawking temperature on the horizon, and Unruh temperature for the fluid inside the…

广义相对论与量子宇宙学 · 物理学 2016-07-15 Subhajit Saha

This work examines the cosmological implications of two functional forms of $f(R,T) = R + \alpha T^n$ gravity: for two different value of $n $ where $n=1$ and $n\neq 1$, and $\alpha$ and $n$ are free parameters. The modified Friedmann…

宇宙学与河外天体物理 · 物理学 2026-02-24 Mustapha Lamaaoune

We establish a relationship between the multipoles of the expansion rate fluctuation field $\eta,$ which capture in an accurate way deviations from isotropy in the redshift-distance relation, and the multipoles of the covariant cosmographic…

宇宙学与河外天体物理 · 物理学 2025-01-06 Basheer Kalbouneh , Christian Marinoni , Roy Maartens

The problem of reproducing dark energy effects is reviewed here with particular interest devoted to cosmography. We summarize some of the most relevant cosmological models, based on the assumption that the corresponding barotropic equations…

广义相对论与量子宇宙学 · 物理学 2013-12-09 Salvatore Capozziello , Mariafelicia De Laurentis , Orlando Luongo , Alan Cosimo Ruggeri

In this paper, we examine the universe's expansion in $ f(R, L_{m}) $ gravity for a particular form of $ f(R, L_{m})=\frac{R}{2}+L_{m}^{n}$. The field equations for flat FLRW metric with matter Lagrangian $ L_{m}=\rho$ are derive. Hubble…

广义相对论与量子宇宙学 · 物理学 2025-02-12 Romanshu Garg , G. P. Singh , Ashwini R Lalke , Saibal Ray

Our objective in this paper is to study the late-time behavior of the universe in a model resulting from a parametrization of the Hubble parameter ($H$) in $f(Q,T)$ gravity. We have considered the flat Friedmann-Lemaitre-Robertson-Walker…

广义相对论与量子宇宙学 · 物理学 2023-04-19 Viraj Kalsariya , Shibesh Kumar Jas Pacif

Using the superfield approach we construct the $n=2$ supersymmetric lagrangian for the FRW Universe with barotropic perfect fluid as matter field. The obtained supersymmetric algebra allowed us to take the square root of the Wheeler-DeWitt…

广义相对论与量子宇宙学 · 物理学 2015-05-13 J. J. Rosales , V. I. Tkach

In the realm of the Bekenstein-Hawking entropy, the thermodynamics of apparent horizon bridges with the usual FLRW (Friedmann-Lema\^{i}tre-Robertson-Walker) equation only for a special case where the matter field is given by a perfect fluid…

广义相对论与量子宇宙学 · 物理学 2022-12-14 Shin'ichi Nojiri , Sergei D. Odintsov , Tanmoy Paul

We consider five dimensional conformal gravity theory which describes an anisotropic extra dimension. Reducing the theory to four dimensions yields Brans-Dicke theory with a potential and a hidden parameter $z$ which implements the…

宇宙学与河外天体物理 · 物理学 2018-01-23 Seyen Kouwn , Phillial Oh , Chan-Gyung Park

In this work, we derive a generalized modified Friedmann equation based on an entropy-area relation that incorporates established modifications, such as volumetric, linear, and logarithmic terms, in addition to novel entropic modifications…

广义相对论与量子宇宙学 · 物理学 2024-12-17 Javier Chagoya , I. Díaz-Saldaña , Mario H. Amante , J. C. López-Domínguez , M. Sabido

This article deals with a cosmological scenario in $ f(R,T) $ gravity for a flat FLRW model of the universe. We consider the $ f(R,T) $ function as $ f(R)+f(T) $ which starts with a quadratic correction of the geometric term $ f(R) $ having…

广义相对论与量子宇宙学 · 物理学 2022-05-03 Ritika Nagpal , J. K. Singh , A. Beesham , Hamid Shabani

In this paper, the dynamical behavior of the accelerated expansion of the universe is discussed within the framework of $f(T)$ gravity, considering power law functional form of $ f(T)=\alpha (-T)^{n}$. Two distinct redshift-dependent…

广义相对论与量子宇宙学 · 物理学 2025-08-29 Shivank Pal , Romanshu Garg , Gyan Prakash Singh , Gauree Shanker

We examine the class of barotropic fluid models of dark energy, in which the pressure is an explicit function of the density, p = f(\rho). Through general physical considerations we constrain the asymptotic past and future behaviors and…

天体物理学 · 物理学 2010-04-21 Eric V. Linder , Robert J. Scherrer

We show that modelling the universe as a pre-geometric system with emergent quantum modes, and then constructing the classical limit, we obtain a new account of space and gravity that goes beyond Newtonian gravity even in the…

综合物理 · 物理学 2007-09-20 Reginald T Cahill

The Hubble relation between distance and redshift is a purely cosmographic relation that depends only on the symmetries of a FLRW spacetime, but does not intrinsically make any dynamical assumptions. This suggests that it should be possible…

广义相对论与量子宇宙学 · 物理学 2016-11-15 Matt Visser , Celine Cattoen

It is nowadays accepted that the universe is undergoing a phase of accelerated expansion as tested by the Hubble diagram of Type Ia Supernovae (SNeIa) and several LSS observations. Future SNeIa surveys and other probes will make it possible…

天体物理学 · 物理学 2009-02-20 S. Capozziello , V. F. Cardone , V. Salzano