Journal
PHYSICAL REVIEW D
Volume 90, Issue 2, Pages -Publisher
AMER PHYSICAL SOC
DOI: 10.1103/PhysRevD.90.023507
Keywords
-
Funding
- French Agence Nationale de la Recherche [ANR-12-BS05-0002]
- European Union (Marie Curie Actions) [PITN-GA-2011-289442]
- Agence Nationale de la Recherche [ANR 2010 BLANC 0413 01]
Ask authors/readers for more resources
We study the cosmology of K-mouflage theories at the background level. We show that the effects of the scalar field are suppressed at high matter density in the early Universe and only play a role in the late time Universe where the deviations of the Hubble rate from its Lambda-CDM counterpart can be of the order five percent for redshifts 1 less than or similar to z less than or similar to 5. Similarly, we find that the equation of state can cross the phantom divide in the recent past and even diverge when the effective scalar energy density goes negative and subdominant compared to matter, preserving the positivity of the squared Hubble rate. These features are present in models for which big bang nucleosynthesis is not affected. We analyze the fate of K-mouflage when the nonlinear kinetic terms give rise to ghosts, particle excitations with negative energy. In this case, we find that the K-mouflage theories can only be considered as an effective description of the Universe at low energy below 1 keV. In the safe ghost-free models, we find that the equation of state always diverges in the past and changes significantly by a few percent since z less than or similar to 1.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available