A simple parametrisation for coupled dark energy

Abstract

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.

18 pages, 7 figures

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Cited by in corpus (10)

• The CosmoVerse White Paper: Addressing observational tensions in cosmology with systematics and fundamental physics
• On the dynamics of a dark sector coupling
• Dissecting kinetically coupled quintessence: phenomenology and observational tests
• Fundamental Physics with ESPRESSO, Constraining a simple parametrisation for varying $\alpha$
• Is there evidence for CIDER in the Universe?
• Coupling quintessence kinetics to electromagnetism
• Coupled quintessence inspired by warm inflation
• Relaxing cosmological constraints on current neutrino masses
• Solving an Interacting Quintessence Model with a Sound Horizon Initial Condition and its Observational Constraints
• Scaling solutions in three-form cosmology