Dodging the dark matter degeneracy while determining the dynamics of dark energy

Abstract

One of the key issues in cosmology is to establish the nature of dark energy, and to determine whether the equation of state evolves with time. When estimating this from distance measurements there is a degeneracy with the matter density. We show that there exists a simple function of the dark energy equation of state and its first derivative which is independent of this degeneracy at all redshifts, and so is a much more robust determinant of the evolution of dark energy than just its derivative. We show that this function can be well determined at low redshift from supernovae using Gaussian Processes, and that this method is far superior to a variety of parameterisations which are also subject to priors on the matter density. This shows that parametrised models give very biased constraints on the evolution of dark energy.

6 pages, 4 figures, it matches the version published in JCAP

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Cited by in corpus (8)

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• Constraints on interacting dark energy models through cosmic chronometers and Gaussian process
• Gaussian processes reconstruction of modified gravitational wave propagation
• Gravity in the infrared and effective nonlocal models
• Hints of dark energy anisotropic stress using Machine Learning
• Reconstruction of the neutrino mass as a function of redshift
• Are $H_0$ and ${\sigma }_8$ tensions generic to present cosmological data?
• Wormholes from cosmological reconstruction based on Gaussian processes