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While in the standard cosmological model the accelerated expansion of the Universe is explained by invoking the presence of the cosmological constant term, it is still unclear the true origin of this stunning observational fact. It is…

广义相对论与量子宇宙学 · 物理学 2015-10-07 Mohammad Malekjani , Tayebe Naderi , Francesco Pace

Knowing the late time evolution of the Universe and finding out the causes for this evolution are the important challenges of modern cosmology. In this work, we adopt a model-independent cosmographic approach and approximate the Hubble…

宇宙学与河外天体物理 · 物理学 2019-01-23 Salvatore Capozziello , Ruchika , Anjan A Sen

We present a complete analysis of the observational constraints and cosmological implications of our Bound Dark Energy (BDE) model aimed to explain the late-time cosmic acceleration of the universe. BDE is derived from particle physics and…

宇宙学与河外天体物理 · 物理学 2019-05-15 Erick Almaraz , Axel de la Macorra

The present epoch of accelerated cosmic expansion is supposed to be driven by an unknown constituent called dark energy, which in the standard model takes the form of a cosmological constant, characterized by a constant equation of state…

宇宙学与河外天体物理 · 物理学 2021-08-30 Sveva Castello , Stéphane Ilić , Martin Kunz

A $\Lambda$CDM model with dark matter that decays into inert relativistic energy on a timescale longer than the Hubble time will produce an expansion history that can be misinterpreted as stable dark matter with time-varying dark energy. We…

宇宙学与河外天体物理 · 物理学 2010-08-27 Sourish Dutta , Robert J. Scherrer

In this paper, we investigate the cosmic evolution within the framework of $f(T)$ gravity using a flat-FRW background and model the universe as consisting of three components: baryonic matter, dark matter, and dark energy. We consider the…

广义相对论与量子宇宙学 · 物理学 2026-02-10 Alireza Amani

Recent observations from the Dark Energy Spectroscopic Instrument (DESI 2025) indicate a weakening of cosmic acceleration at low redshifts $z < 1$, with effective dark energy equation of state parameters $w_0 > -1$ and $w_a < 0$. We…

宇宙学与河外天体物理 · 物理学 2025-03-28 John W. Moffat

We study dark energy through the viewpoints of parametric and nonparametric analyses of late-time cosmological data. We consider four Hubble parameter priors reflecting the Hubble tension and make use of two phenomenological functions,…

宇宙学与河外天体物理 · 物理学 2022-04-27 Reginald Christian Bernardo , Daniela Grandón , Jackson Levi Said , Víctor H. Cárdenas

Recent observational evidences of accelerating phase of the universe strongly demand that the dominating matter in the universe is in the form of dark energy. In this work, we study the evolution of the apparent and event horizons for…

广义相对论与量子宇宙学 · 物理学 2015-05-28 Ritabrata Biswas , Nairwita Mazumder , Subenoy Chakraborty

The question of the origin of the recent acceleration of the Universes expansion is still pending. What is making the situation even worst, it is impossible to distinguish the vast majority of the proposed models of the dynamical dark…

宇宙学与河外天体物理 · 物理学 2015-11-20 Tomasz Denkiewicz

Adaptive SPH and N-body simulations were carried out to study the evolution of the equilibrium structure of dark matter halos that result from the gravitational instability and fragmentation of cosmological pancakes. Such halos resemble…

天体物理学 · 物理学 2009-11-06 Marcelo Alvarez , Paul R. Shapiro , Hugo Martel

Once the temperature of a bosonic gas is smaller than the critical, density dependent, transition temperature, a Bose - Einstein Condensation process can take place during the cosmological evolution of the Universe. Bose - Einstein…

广义相对论与量子宇宙学 · 物理学 2015-06-04 Tiberiu Harko , Gabriela Mocanu

An interesting feature of a cosmological phase transition can be a stage of exponential expansion (supercooling). The modified expansion history and the entropy injection at reheating, can affect the final energy fraction of dark matter. In…

高能物理 - 唯象学 · 物理学 2025-12-19 Davide Racco , Alfredo Stanzione

We study the linear cosmological evolution of inelastic self-interacting dark matter in a two-component dark sector with a small mass splitting, assuming thermal initial conditions for the two species. We derive the coupled background and…

宇宙学与河外天体物理 · 物理学 2026-04-28 Xin-Chen Duan , Yue-Lin Sming Tsai , Ziwei Wang

We have studied constraints on the equation of state, $w$, and speed of sound, c_s, of the dark energy from a joint analysis of data from the cosmic microwave background, large scale structure and type-Ia supernovae. We find that current…

天体物理学 · 物理学 2009-11-10 Steen Hannestad

We present numerical calculation of the evolution of a background space-time metric and sub-horizon matter density perturbations in viable $f(R)$ gravity models of present dark energy and cosmic acceleration. We found that viable models…

宇宙学与河外天体物理 · 物理学 2011-01-25 Hayato Motohashi , Alexei A. Starobinsky , Jun'ichi Yokoyama

In most models of dark energy the structure formation stops when the accelerated expansion begins. In contrast, we show that the coupling of dark energy to dark matter may induce the growth of perturbations even in the accelerated regime.…

天体物理学 · 物理学 2009-11-07 Luca Amendola , Domenico Tocchini-Valentini

Recently, a supersymmetric model of dark energy coupled to cold dark matter, the supersymmetron, has been proposed. In the absence of cold dark matter, the supersymmetron field converges to a supersymmetric minimum with a vanishing…

宇宙学与河外天体物理 · 物理学 2013-05-30 Philippe Brax , Anne-Christine Davis , Hans A. Winther

Dark energy cosmologies with an equation of state parameter $w$ less than -1 are often found to violate the null energy condition and show unstable behaviour. A solution to this problem may require the existence of a consistent effective…

高能物理 - 理论 · 物理学 2009-04-22 Ben M. Leith , Ishwaree P. Neupane

Dark energy is now one of the most important and topical problems in cosmology. The first step to reveal its nature is to detect the evolution of dark energy or to prove beyond doubt that the cosmological constant is indeed constant.…

宇宙学与河外天体物理 · 物理学 2011-01-21 Krzysztof Bolejko