Non-linear coupling in the dark sector as a running vacuum model

Abstract

In this work we study a phenomenological non-gravitational interaction between dark matter and dark energy. The scenario studied in this work extends the usual interaction model proportional to the derivative of the dark component density adding to the coupling a non-linear term of the form $Q={\rho }^{\prime }/3(\alpha +\beta \rho )$. This dark sector interaction model could be interpreted as a particular case of a running vacuum model of the type $\Lambda (H)=n_0+n_1{H}^2+n_2{H}^4$ in which the vacuum decays into dark matter. For a flat FRW Universe filled with dark energy, dark matter and decoupled baryonic matter and radiation we calculate the energy density evolution equations of the dark sector and solve them. The different sign combinations of the two parameters of the model show clear qualitative different cosmological scenarios, from basic cosmological insights we discard some of them. The linear scalar perturbation equations of the dark matter were calculated. Using the CAMB code we calculate the CMB and matter power spectra for some values of the parameters $\alpha$ and $\beta$ and compare it with $\Lambda$CDM. The model modify mainly the lower multipoles of the CMB power spectrum remaining almost the same the high ones. The matter power spectrum for low wave numbers is not modified by the interaction but after the maximum it is clearly different. Using observational data from Planck, and various galaxy surveys we obtain the constraints of the parameters, the best fit values obtained are the combinations $\alpha =(3.7\pm 7)\times 10^{-4}$, $-(1.5\times 10^{-5}{\mathrm{eV}}^{-1}{)}^4\ll \beta <(0.07{\mathrm{eV}}^{-1}{)}^4$.

13 pages, 7 figures

References in corpus (13)

• Dynamics of dark energy
• The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: cosmological analysis of the DR12 galaxy sample
• The Clustering of the SDSS DR7 Main Galaxy Sample I: A 4 per cent Distance Measure at z=0.15
• Indications of a late-time interaction in the dark sector
• Echo of interactions in the dark sector
• Dark Matter: A Primer
• Constraints on the Coupling between Dark Energy and Dark Matter from CMB data
• Hubble expansion and structure formation in the "running FLRW model" of the cosmic evolution
• Cosmological constraints on a decomposed Chaplygin gas
• Inhomogeneous vacuum energy
• Post-$Planck$ constraints on interacting vacuum energy
• Distinguishing interacting dark energy from wCDM with CMB, lensing, and baryon acoustic oscillation data
• Running Vacuum Cosmological Models: Linear Scalar Perturbations

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