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Inspired by an exponential $f(R)$ gravity model studied in the literature, in this work we introduce a new and viable $f(Q)$ gravity model, which can be represented as a perturbation of $\Lambda$CDM. Typically, within the realm of $f(Q)$…

宇宙学与河外天体物理 · 物理学 2024-01-31 A. Oliveros , Mario A. Acero

In this work, we explore dark energy models, mainly ghost, generalized ghost, and generalized ghost pilgrim dark energy models within the framework of fractal cosmology. To obtain solutions for the field equations, we employ a…

广义相对论与量子宇宙学 · 物理学 2024-12-20 S. R. Bhoyar , Yash B. Ingole , A. P. Kale

We analyse the emergent cosmological dynamics corresponding to the mean field hydrodynamics of quantum gravity condensates, in the tensorial group field theory formalism. We focus in particular on the cosmological effects of fundamental…

广义相对论与量子宇宙学 · 物理学 2022-01-05 Daniele Oriti , Xiankai Pang

We investigate the generalized Quantum Chromodynamics (QCD) ghost model of dark energy in the framework of Einstein gravity. First, we study the non-interacting generalized ghost dark energy in a flat Friedmann-Robertson-Walker (FRW)…

广义相对论与量子宇宙学 · 物理学 2015-06-11 Esmaeil Ebrahimi , Ahmad Sheykhi , Hamzeh Alavirad

We derive conditions under which f(G) gravity models, whose Lagrangian densities f are written in terms of a Gauss-Bonnet term G, are cosmologically viable. The most crucial condition to be satisfied is that f_GG, the second derivative of f…

高能物理 - 理论 · 物理学 2009-04-18 Antonio De Felice , Shinji Tsujikawa

In this paper, we carry out a study of viable cosmological models in $f(R)$-gravity at the background level. We use observable parameters like $\Omega$ and $\gamma$ to form autonomous system of equations and show that the models under…

宇宙学与河外天体物理 · 物理学 2010-05-28 Amna Ali , Radouane Gannouji , M. Sami , Anjan A. Sen

We investigate a generalized power-law dark energy equation of state of the form $p = w\rho - \beta\rho^m$ in a flat FLRW universe, analyzing its dynamical stability and thermodynamic consistency. The model exhibits a rich phase space…

广义相对论与量子宇宙学 · 物理学 2025-07-08 S. Kazemi , M. A. Ramzanpour , E. Yusofi , A. R. Amani

In order to explain the late-time acceleration of the Universe, we present a reconstructed version of the $f(Q)$ gravity theory in this work, which is inspired by the integrating the fractional holographic dark energy with the Hubble…

广义相对论与量子宇宙学 · 物理学 2025-12-04 Rajdeep Mazumdar , Kalyan Malakar , Kalyan Bhuyan

We construct phantom energy models with the equation-of-state parameter $w$ such that $w<-1$, but finite-time future singularity does not occur. Such models can be divided into two classes: (i) energy density increases with time ("phantom…

广义相对论与量子宇宙学 · 物理学 2015-06-03 Artyom V. Astashenok , Shin'ichi Nojiri , Sergei D. Odintsov , Artyom V. Yurov

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

The dark energy transition between quintessence ($w>-1$) and phantom ($w<-1$) regimes (the crossing of the cosmological constant boundary) is studied using the dark energy equation of state. Models characterized by this type of transition…

天体物理学 · 物理学 2009-11-11 Hrvoje Stefancic

We investigate de Sitter solutions in non-local gravity as well as in non-local gravity with Lagrange constraint multiplier. We examine a condition to avoid a ghost and discuss a screening scenario for a cosmological constant in de Sitter…

高能物理 - 理论 · 物理学 2015-05-27 Kazuharu Bamba , Shin'ichi Nojiri , Sergei D. Odintsov , Misao Sasaki

In this paper, we study an interacting holographic dark energy model in the framework of fractal cosmology. The features of fractal cosmology could pass ultraviolet divergencies and also make a better understanding of the universe in…

广义相对论与量子宇宙学 · 物理学 2018-10-16 Ehsan Sadri , Martiros Khurshudyan , Surajit Chattopadhyay

In this manuscript, we use the correspondence principle to construct the generalized ghost dark energy $f(Q)$ model, where $Q$ is the non-metricity. For this purpose, we use the Friedman-Robertson-Walker universe model with power-law scale…

广义相对论与量子宇宙学 · 物理学 2024-03-05 M. Sharif , Madiha Ajmal

We consider general curvature-invariant modifications of the Einstein-Hilbert action that become important only in regions of extremely low space-time curvature. We investigate the far future evolution of the universe in such models,…

The horizon of a flat Friedmann--Robertson--Walker (FRW) universe is considered to be dynamic when the Hubble parameter $H$ and the Hubble radius $r_{H}$ vary with time, unlike for de Sitter universes. To clarify the thermodynamics on a…

广义相对论与量子宇宙学 · 物理学 2023-10-17 Nobuyoshi Komatsu

The following issue is addressed: how the addition of a Gauss-Bonnet term (generically coming from most fundamental theories, as string and M theories), to a viable model, can change the specific properties, and even the physical nature, of…

广义相对论与量子宇宙学 · 物理学 2016-06-15 Anna Escofet , Emilio Elizalde

We bring forward a generalized pressure dark energy (GPDE) model to explore the evolution of the universe. This model has covered three common pressure parameterization types and can be reconstructed as quintessence and phantom scalar…

宇宙学与河外天体物理 · 物理学 2019-10-23 Jun-Chao Wang , Xin-He Meng

Within the framework of modified teleparallel gravity, we reconstruct a f(T) model corresponding to the QCD ghost dark energy scenario. For a spatially flat FRW universe containing only the pressureless matter, we obtain the time evolution…

综合物理 · 物理学 2014-01-30 K. Karami , A. Abdolmaleki , S. Asadzadeh , Z. Safari

In this paper, the dynamical behavior of the accelerated expansion of the universe is studied within the framework of $f(T)$ gravity by considering a well-motivated functional form of $f(T)$. A specific form of the Hubble parameter is…

广义相对论与量子宇宙学 · 物理学 2026-03-20 Khomesh R. Patle , G. P. Singh