Neutrino Condensation as Dark Energy

Motivated by the seeming coincidence of the neutrino mass scale and the dark energy scale, we propose to explain the cosmic dark energy by neutrino condensation. Similar to the idea of top-quark condensation, we assume that a four-fermion interaction for the third-family neutrino is induced from some unknown new dynamics which is strong enough to cause neutrino condensation. In the low-energy effective theory the resultant composite scalar field with a very small vev of about 10^{-3} eV is interpreted as the dark energy field. The tiny neutrino masses can be generated from such a small vev without see-saw mechanism