Home Cosmology Null test for interactions in the dark sector. (arXiv:1812.02333v1 )

Null test for interactions in the dark sector. (arXiv:1812.02333v1 [astro-ph.CO])


Authors: Rodrigo von Marttens, Valerio Marra, Luciano Casarini, J. E. Gonzalez, Jailson Alcaniz

Since there is no known symmetry in Nature that prevents a non-minimal
coupling between the dark energy (DE) and cold dark matter (CDM) components,
such a possibility constitutes an alternative to standard cosmology, with its
theoretical and observational consequences being of great interest. In this
paper we propose a new null test on the standard evolution of the dark sector
based on the time dependence of the ratio between the CDM and DE energy
densities which, in the standard $Lambda$CDM scenario, scales necessarily as
$a^{-3}$. We use the latest measurements of type Ia supernovae, cosmic
chronometers and angular baryonic acoustic oscillations to reconstruct the
expansion history using model-independent Machine Learning techniques, namely,
the Linear Model formalism and Gaussian Processes. We find that while the
standard evolution is consistent with the data at $3sigma$ level, some
deviations from the $Lambda$CDM model are found at low redshifts, which may be
associated with the current tension between local and global determinations of


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