Long range forces from the cosmological neutrino background
Abstract The cosmological neutrino background will mediate long range forces between objects. For a background of temperature T , the potential decreases as 1 r 5 for r ⪢ 1 T and as 1 r for r ⪡ 1 T . These forces have large spin-dependent components. If the neutrino background is nonrelativistic, the long range forces are enhanced by a factor of the inverse neutrino velocity.