Model of dark matter and dark energy based on gravitational polarization
The phenomenology of dark matter which is associated with MOND (MOdified Newtonian Dynamics) can be naturally interpreted in terms of a mechanism of "gravitational polarization" of a medium made of dipole moments polarized in the gravitational field. In this interpretation MOND does not appear as a modification of the fundamental law of gravity, but as due to a new form of dark matter, whose dynamics is different from the ordinary dark matter made of (say) super-symmetric particles. We propose a model for describing the dipolar dark matter in standard general relativity. We show in this model that (i) the phenomenology of MOND at galactic scales is the consequence of the mechanism of polarization, (ii) the dipolar dark matter is indistinguishable from standard dark matter at first-order cosmological perturbations (and is thus consistent with CMB fluctuations), (iii) the cosmological constant must be of the order of magnitude of the square of the MOND acceleration scale (in good agreement with observations).