A simple parametrisation for coupled dark energy

As an alternative to the popular parametrisations of the dark energy equation of state, we construct a quintessence model where the scalar field has a linear dependence on the number of e-folds. Constraints on more complex models are typically limited by the degeneracies that increase with the numbe...

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Bibliographic Details
Published inarXiv.org
Main Authors Vitor da Fonseca, Barreiro, Tiago, Nunes, Nelson J
Format Paper Journal Article
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 16.12.2021
Subjects
Cold dark matter
Constraint modelling
Coupling
Dark energy
Dark matter
Energy transfer
Equations of state
Parameterization
Physics - Cosmology and Nongalactic Astrophysics
Physics - General Relativity and Quantum Cosmology
Quintessence (cosmology)
Scalars
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Summary:As an alternative to the popular parametrisations of the dark energy equation of state, we construct a quintessence model where the scalar field has a linear dependence on the number of e-folds. Constraints on more complex models are typically limited by the degeneracies that increase with the number of parameters. The proposed parametrisation conveniently constrains the evolution of the dark energy equation of state as it allows for a wide variety of time evolutions. We also consider a non-minimal coupling to cold dark matter. We fit the model with Planck and KiDS observational data. The CMB favours a non-vanishing coupling with energy transfer from dark energy to dark matter. Conversely, gravitational weak lensing measurements slightly favour energy transfer from dark matter to dark energy, with a substantial departure of the dark energy equation of state from -1.
ISSN:2331-8422
DOI:10.48550/arxiv.2104.14889