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相关论文: When did cosmic acceleration start? How fast was t…

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The discovery that we live in an accelerating universe changed drastically the paradigm of physics and introduced the concept of \textit{dark energy}. In this work, we present a brief historical description of the main events related to the…

宇宙学与河外天体物理 · 物理学 2025-02-04 Rodrigo von Marttens , Jailson Alcaniz

The properties of the Galactic supernova remnant SN 1006 are theoretically reanalysed. Nonlinear kinetic theory is used to determine the acceleration efficiency of cosmic rays (CRs) in the supernova remnant SN 1006. The known range of…

高能天体物理现象 · 物理学 2011-03-22 E. G. Berezhko , L. T. Ksenofontov , H. J. Voelk

A new parametrization of the Hubble parameter is proposed to explore the issue of the cosmological landscape. The constraints on model parameters are derived through the Markov Chain Monte Carlo (MCMC) method by employing a comprehensive…

宇宙学与河外天体物理 · 物理学 2024-05-06 L. Sudharani , Kazuharu Bamba , N. S. Kavya , V. Venkatesha

Understanding the evolution of dark energy poses a significant challenge in modern cosmology, as it is responsible for the universe's accelerated expansion. In this study, we focus on a specific $f(T)$ cosmological model and analyze its…

宇宙学与河外天体物理 · 物理学 2024-05-14 A. Zhadyranova , M. Koussour , S. Bekkhozhayev , V. Zhumabekova , J. Rayimbaev

In this work, the cosmic solutions, particularly the well-known $\Lambda$CDM model, are investigated in the framework of the Gauss-Bonnet gravity, where the gravitational action incorporates the Gauss-Bonnet invariant function. We utilize a…

广义相对论与量子宇宙学 · 物理学 2024-09-26 N. Myrzakulov , Anirudh Pradhan , Archana Dixit , S. H. Shekh

Quantum cosmology describes universe as a relativistic object with an evolution defined by an equation for the energy density corresponding to the least action principle: (Taganov, 2008). In quantum cosmology this equation plays the same…

综合物理 · 物理学 2008-11-26 Igor N. Taganov

We compile a list of 28 independent measurements of the Hubble parameter between redshifts 0.07 < z < 2.3 and use this to place constraints on model parameters of constant and time-evolving dark energy cosmologies. These H(z) measurements…

宇宙学与河外天体物理 · 物理学 2015-06-12 Omer Farooq , Bharat Ratra

Type Ia Supernovae hold great promise to measure the cosmic deceleration. The diversity observed among these explosions, however, complicates their ability to measure cosmological parameters considerably. The comparison of near and distant…

天体物理学 · 物理学 2007-05-23 B. Leibundgut

We study the late-time cosmology in $f(R, G)=R+\alpha R^{2}+\beta e^{\gamma G}$, using a logarithmic parametrization of the deceleration parameter $q(z)=q_{0}+q_{1}sin[log(1+z)]$. The Hubble parameter $H(z)$ is reconstructed and model…

广义相对论与量子宇宙学 · 物理学 2025-06-10 Amit Samaddar , S. Surendra Singh

We investigate the properties of a cosmological scenario which undergoes a gravitational phase transition at late times. In this scenario, the Universe evolves according to general relativity in the standard, hot Big Bang picture until a…

天体物理学 · 物理学 2013-05-29 Robert R. Caldwell , William Komp , Leonard Parker , Daniel A. T. Vanzella

We construct cosmological model in nonmetricity scalar functional gravitational Lagrangian $f(Q)$ which describes the dynamical evolution of the late accelerating universe. Cosmological models are constructed considering different…

广义相对论与量子宇宙学 · 物理学 2025-04-23 Bikash Chandra Roy , Aroonkumar Beesham , Bikash Chandra Paul

The explanation of the accelerated expansion of the Universe poses one of the most fundamental questions in physics and cosmology today. If the acceleration is driven by some form of dark energy, one can try to constrain the parameters…

宇宙学与河外天体物理 · 物理学 2015-06-05 Marek Demianski , Ester Piedipalumbo , Claudio Rubano , Paolo Scudellaro

An overview is given of the current status of the theory and observations of the acceleration of the expansion of the observable part of the Universe. Contents 1. Historical Introduction 2. Friedmann equations and cosmological acceleration…

宇宙学与河外天体物理 · 物理学 2020-12-16 Sergei I. Blinnikov , Alexander D. Dolgov

Parameters that quantify the acceleration of cosmic expansion are conventionally determined within the standard Friedmann-Lemaitre-Robertson-Walker (FLRW) model, which fixes spatial curvature to be homogeneous. Generic averages of…

宇宙学与河外天体物理 · 物理学 2017-09-15 Lawrence H. Dam , Asta Heinesen , David L. Wiltshire

Supernovae are bright luminous stellar objects observable up to redshifts close to z~1. They are used to probe the geometry of the Universe and its expansion rate by applying different methods. In this article, I review various approaches…

天体物理学 · 物理学 2011-04-15 P. Ruiz-Lapuente

On the basis of homogeneous and isotropic Friedmann-Lemaitre-Robertson-Walker (FLRW) geometry, solutions to the issues of cosmic acceleration and dark energy are being put forth within the context of $f\left( Q\right)$ gravity. We take into…

广义相对论与量子宇宙学 · 物理学 2023-03-28 M. Koussour , Simran Arora , Dhruba Jyoti Gogoi , M. Bennai , P. K. Sahoo

In this paper, a cosmological model of the Universe is presented in $f(Q,T)$ gravity and the parameters are constrained by cosmological data sets. Initially, a generalised form of $f(Q,T)$ model is used as $f(Q,T)=-\lambda_{1}…

广义相对论与量子宇宙学 · 物理学 2024-03-21 A. S. Agrawal , B. Mishra , S. K. Tripathy

To recreate the cosmological models, we employed the parametrization approach in modified teleparallel Gauss-Bonnet gravity. It has been interesting to apply the parametrization approach to investigate cosmological models. The real benefit…

广义相对论与量子宇宙学 · 物理学 2022-12-29 Santosh V. Lohakare , B. Mishra , S. K. Maurya , Ksh. Newton Singh

The transient acceleration which the current cosmic acceleration is not eternal is possible by introducing the interaction between dark matter and dark energy. If the energy transfer is from dark energy to dark matter, then it is possible…

宇宙学与河外天体物理 · 物理学 2014-01-29 Xi-ming Chen , Yungui Gong , Emmanuel N. Saridakis

In the Friedmann cosmology the deceleration of the expansion $q$ plays a fundamental role. We derive the deceleration as a function of redshift $q(z)$ in two scenarios: $\Lambda$CDM model and modified Chaplygin gas ($MCG$) model. The…

宇宙学与河外天体物理 · 物理学 2011-05-12 Alan M. Velásquez-Toribio , Maria Luíza Bedran