New field theory effect at energy densities close to the dark energy density

By Alexander Kaganovich, Ben Gurion University

A field theory is proposed where the same "primordial" fermion field at different densities can be either in states corresponding to regular fermionic matter or in states presumably corresponding to the dark fermionic matter. In regime of the fermion densities typical for normal particle physics, each of the primordial fermions splits into three generations identified with regular fermions. Coupling constant of the dilaton (playing the role of the quintessence-like scalar field) to fermions ofthe first two generations automatically appears to be extremely suppressed, that solves the fifth force problem. When fermion energy density becomes comparable with vacuum energy density, the theory allows new type of states. The possibility of such Cosmo-Low Energy Physics (CLEP) states is demonstrated by means of solutions of the field theory equations describing FRW universe filled by homogeneous scalar field and uniformly distributed nonrelativistic neutrinos. Neutrinos in CLEP state are drawn into cosmological expansion by means of dynamically changing their own parameters. Some of the features of the CLEP state in the late time universe are: neutrino masses increase as a^3/2 (a=a(t) is the scale factor); neutrino energy density scales as a sort of dark energy and approaches constant as a→∞; this cold dark matter possesses negative pressure and its equation of state approaches that of the cosmological constant as a→∞; the total energy density of such universe is less than it would be in the universe free of fermionic matter at all. The latter means that nonrelativistic neutrinos are able to produce expanding bubbles of the CLEP state playing the role of a true "cosmological vacuum" sorrounded by a "normal" vacuum. A hypothesis is suggested that vacuum of voids is the CLEP state whereas vacuum in galaxy halos is normal one.