Technically natural dark energy from Lorentz breaking
Wed, Feb. 29th 2012, 14:15
Salle Claude Itzykson, Bât. 774, Orme des Merisiers
I will present a model of dark energy with a technically natural small contribution to cosmic acceleration. The proposed acceleration mechanism appears generically in the low-energy limit of gravitational theories with violation of Lorentz invariance that contain a derivatively coupled scalar field. Furthermore, the model is a valid effective field theory up to a high cutoff. Even if the expansion history of the Universe is essentially indistinguishable from that of $Lambda$CDM, cosmological perturbations allow to discriminate between both models. I'll show how the matter power spectrum is enhanced at subhorizon scales for realistic parameters, which may be tested with current cosmological data.
Contact : ccaprini