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Measurements suggest that our universe has a substantial dark energy component. The most recent data on type Ia supernovae give a dark energy density which is in good agreement with other measurements if the dark energy is assumed to be a…

Astrophysics · Physics 2009-11-10 Duane A. Dicus , Wayne W. Repko

A new single-dynamical-scalar-field model of dark energy is proposed, in which either higher derivative terms nor structures of extra dimension are needed. With the help of a fixed background vector field, the parameter for the effective…

Astrophysics · Physics 2007-05-23 Chao-Guang Huang , Han-Ying Guo

Recently, the WMAP group has published their five-year data and considered the constraints on the time evolving equation of state of dark energy for the first time from the WMAP distance information. In this paper, we study the…

Astrophysics · Physics 2011-02-11 Hong Li , Jun-Qing Xia , Gong-Bo Zhao , Zu-Hui Fan , Xinmin Zhang

We examine the influence of percent-level dark energy corrections to the nonlinear matter power spectrum on constraints of the dark energy equation of state from future weak lensing probes. We explicitly show that a poor approximation (off…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-28 Shahab Joudaki , Asantha Cooray , Daniel E. Holz

The main aim of this work is to use a model-independent approach, along with late-time observational probes, to reconstruct the dark energy (DE) equation of state $w_{\rm DE}(z)$. Our analysis showed that, for a late time universe, $w_{\rm…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-23 Luis A. Escamilla , Supriya Pan , Eleonora Di Valentino , Andronikos Paliathanasis , J. Alberto Vázquez , Weiqiang Yang

We propose a new Dark Energy parametrization based on the dynamics of a scalar field. We use an equation of state w=(x-1)/(x+1), with x=E_k/V, the ratio of kinetic energy E_k=\dotphi^2/2 and potential V. The equation of motion gives…

General Relativity and Quantum Cosmology · Physics 2016-04-27 Axel de la Macorra

We constrain the dark energy equation of state parameter, $w$, using the power spectrum of the thermal Sunyaev-Zeldovich (tSZ) effect. We improve upon previous analyses by taking into account the trispectrum in the covariance matrix and…

Cosmology and Nongalactic Astrophysics · Physics 2018-04-11 Boris Bolliet , Barbara Comis , Eiichiro Komatsu , Juan Francisco Macías-Pérez

Cosmological constraints on a time-varying dark energy equation of state are fundamentally limited by the integral structure through which the equation of state enters cosmological observables. We rigorously derive the linear response…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-13 Seokcheon Lee

Constraining the Dark Energy (DE) equation of state, w, is one of the primary science goals of ongoing and future cosmological surveys. In practice, with imperfect data and incomplete redshift coverage, this requires making assumptions…

Cosmology and Nongalactic Astrophysics · Physics 2017-10-18 Marco Raveri , Philip Bull , Alessandra Silvestri , Levon Pogosian

Dark energy (DE) models with many free parameters are often considered excessive, as constraining all parameters poses a significant challenge. While such models offer greater flexibility to probe the DE sector in more detail. With the…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-25 Hanyu Cheng , Supriya Pan , Eleonora Di Valentino

In this work, we present a cosmological model in which the cosmological constant term is replaced by the Kretschmann scalar at the level of the action. In this way, it becomes possible to implement a model of dynamical dark energy. After…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-21 A. B. Fernandes , S. H. Pereira , J. F. Jesus , D. M. Soares Junior

In this paper we discuss possible consequences of a manifestly non-commutative and $T$-duality covariant formulation of string theory on dark energy, when the correspondence between short distance (UV) and long distance (IR) physics is…

High Energy Physics - Theory · Physics 2025-03-28 Sunhaeng Hur , Vishnu Jejjala , Michael J. Kavic , Djordje Minic , Tatsu Takeuchi

We consider a generic description of interacting dynamical Dark Energy, characterized by an equation of state with a time dependent coefficient $w(t)$, and which may interact with both radiation and matter. Without referring to any…

General Relativity and Quantum Cosmology · Physics 2019-08-20 Marco Bonici , Nicola Maggiore

Understanding of the nature of dark energy, which appears to drive the expansion of the universe, is one of the central problems of physical cosmology today. In an earlier paper [Daly & Djorgovski (2003)] we proposed a novel method to…

Astrophysics · Physics 2009-11-10 Ruth A. Daly , S. G. Djorgovski

We compare current and forecasted constraints on dynamical dark energy models from Type Ia supernovae and the cosmic microwave background using figures of merit based on the volume of the allowed dark energy parameter space. For a…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Michael J. Mortonson , Dragan Huterer , Wayne Hu

We introduce a new parametrization for the dark energy, led by the same idea to the linear expansion of the equation of state in scale factor $a$ and in redshift $z$, which diverges neither in the past nor future and contains the same…

Cosmology and Nongalactic Astrophysics · Physics 2015-07-01 Ozgur Akarsu , Tekin Dereli , J. Alberto Vazquez

We investigate whether future measurements of high redshift standard candles (HzSCs) will be a powerful probe of dark energy, when compared to other types of planned dark energy measurements. Active galactic nuclei and gamma ray bursts have…

Cosmology and Nongalactic Astrophysics · Physics 2014-06-05 A. L. King , T. M. Davis , K. Denney , M. Vestergaard , D. Watson

The latest cosmological constraints on the sum of the neutrino masses depend on prior physical assumptions about the mass spectrum. To test the accordance of cosmological and laboratory constraints in the absence of such priors, we…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-14 Willem Elbers , Carlos S. Frenk , Adrian Jenkins , Baojiu Li , Silvia Pascoli

We present a model in which the equation of state parameter w approaches -1 near a particular value of z, and has significant negative values in a restricted range of z. For example, one can have w ~ -1 near z = 1, and w > -0.2 from z = 0…

High Energy Physics - Phenomenology · Physics 2012-08-27 B. H. J. McKellar , T. Goldman , G. J. Stephenson, , P. M. Alsing

Recent attempts to fit Type Ia supernova data by modeling the dark energy density as a truncated Taylor series have suggested the possibility of metamorphosis, i.e., a rapidly evolving equation of state parameter, w_DE(z). However, we show…

Astrophysics · Physics 2009-11-10 J. Jonsson , A. Goobar , R. Amanullah , L. Bergstrom