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The cosmographic expansion history of the universe is investigated by using the 557 type Ia supernovae from the Union2 Compilation set along with the current estimates involving the product of the CMB acoustic scale $\ell_{A}$ and the BAO…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 B. Santos , J. C. Carvalho , J. S. Alcaniz

The recent observations support that our universe is flat and expanding with acceleration. A quintessence model with a general relation between the quintessence potential and the quintessence kinetic energy was proposed to explain the…

Astrophysics · Physics 2009-11-10 Yungui Gong

We study the cosmological evolution of scalar fields that arise from a phase transition at some energy scale $\Lm_c$. We focus on negative power potentials given by $V=c\Lm_c^{4+n}\phi^{-n}$ and restrict the cosmological viable values of…

Astrophysics · Physics 2009-11-07 A. de la Macorra , C. Stephan-Otto

While modelling our late time cosmically accelerated universe, it is popular to involve different dark energy models, the equation of state of which can be taken as a function of the redshift and some unknown parameters. Barboza and Alcaniz…

General Physics · Physics 2019-09-25 Swetalina Bhowmik , Ritabrata Biswas

In the current study, we investigate a scalar field cosmological model with Lyra's geometry to explain the present cosmic expansion in a homogeneous and isotropic flat FRW universe. In Einstein's field equations, we presupposed a variable…

General Relativity and Quantum Cosmology · Physics 2025-11-19 Vinod Kumar Bhardwaj , Anil Kumar Yadav , Lalit Kumar Gupta , Rajendra Prasad , Sudhir Kumar Srivastava

Recent observational indications of an accelerating universe enhance the interest in studying models with a cosmological constant. We investigate cosmological expansion (FRW metric) with $\Lambda>0$ for a general linear equation of state…

General Relativity and Quantum Cosmology · Physics 2016-08-31 A. S. Silbergleit

This paper explores models of the FLRW universe that incorporate a time-varying cosmological term $\Lambda(t)$. Specifically, we assume a power-law form for the cosmological term as a function of the scale factor: $\Lambda(t)=\Lambda_{0}…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-14 M. Koussour , N. Myrzakulov , J. Rayimbaev

We perform a minisuperspace analysis of an information-theoretic nonlinear Wheeler-deWitt (WDW) equation for de Sitter universes. The nonlinear WDW equation, which is in the form of a difference-differential equation, is transformed into a…

General Relativity and Quantum Cosmology · Physics 2012-04-02 Rajesh R. Parwani , Siti Nursaba Tarih

We compare the maximal abundance of massive systems predicted in different dynamical dark energy (DDE) models at high redshifts z = 4-7 with the measured abundance of the most massive galaxies observed to be already in place at such…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-27 N. Menci , A. Grazian , M. Castellano , P. Santini , E. Giallongo , A. Lamastra , F. Fortuni , A. Fontana , E. Merlin , T. Wang , D. Elbaz , N. G. Sanchez

Most parameterizations of the dark energy equation of state do not reflect realistic underlying physical models. Here, we develop a relatively simple description of dark energy based on the dynamics of a scalar field which is exact in the…

Astrophysics · Physics 2008-11-26 Robert Crittenden , Elisabetta Majerotto , Federico Piazza

We focus on uncertainties in supernova measurements, in particular of individual magnitudes and redshifts, to review to what extent supernovae measurements of the expansion history of the universe are likely to allow us to constrain a…

Astrophysics · Physics 2011-05-12 Lawrence M. Krauss , Katherine Jones-Smith , Dragan Huterer

In this paper, we study a cosmological model in the background of FLRW space time by assuming an appropriate parametrization in the form of a differential equation in terms of energy density of scalar field $ \rho_{\phi} $, which is defined…

General Physics · Physics 2020-04-09 J. K. Singh , Ritika Nagpal

In this work we examine the 2025 DESI analysis of dark energy, which suggests that dark energy is evolving in time with an increasing equation of state $w$. We explore a wide range of quintessence models, described by a potential function…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-20 Husam Adam , Mark P. Hertzberg , Daniel Jiménez-Aguilar , Iman Khan

Reconstructing the evolution history of the dark energy equation of state parameter $w(z)$ directly from observational data is highly valuable in cosmology, since it contains substantial clues in understanding the nature of the accelerated…

Cosmology and Nongalactic Astrophysics · Physics 2016-08-31 Zhi-E Liu , Hao-Ran Yu , Tong-Jie Zhang , Yan-Ke Tang

In light of recent study on the dark energy models that manifest an equation of state $w<-1$, we investigate the cosmological evolution of phantom field in a specific potential, exponential potential in this paper. The phase plane analysis…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Jian-gang Hao , Xin-zhou Li

The model-independent piecewise parametrizations (0-spline, linear-spline and cubic-spline) are used to estimate constraints of equation of state of dark energy ($w_{de}$) from current observational data (including SNIa, BAO and Hubble…

Cosmology and Nongalactic Astrophysics · Physics 2012-04-11 Qiping Su , Xi He , Rong-Gen Cai

Currently there is a variety of scalar field models to explain the late time acceleration of the Universe. This includes the standard canonical and non-canonical scalar field models together with recently proposed Galileon scalar field…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Shruti Thakur , Akhilesh Nautiyal , Anjan A Sen , T R Seshadri

We derive a lower bound on the field excursion for the tachyon inflation, which is determined by the amplitude of the scalar perturbation and the number of $e$-folds before the end of inflation. Using the relation between the observables…

General Relativity and Quantum Cosmology · Physics 2017-08-17 Qin Fei , Yungui Gong , Jiong Lin , Zhu Yi

In this work, we construct time-dependent potentials for the Schr\"odinger equation via supersymmetric quantum mechanics. The generated potentials have a quantum state with the property that after a particular threshold time $t_F$, when the…

Quantum Physics · Physics 2022-05-25 Izamar Gutiérrez Altamirano , Alonso Contreras-Astorga , Alfredo Raya

Recent observational indications of an accelerating universe enhance the interest in studying models with a cosmological constant. We investigate cosmological expansion (FRW metric) with $\Lambda>0$ for a general linear equation of state…

Astrophysics · Physics 2009-11-07 A. S. Silbergleit
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