Key points are not available for this paper at this time.
Instantons lead to strong correlations between up and down quarks with spin zero and antisymmetric color wave functions. In cold and dense matter, n₁>n₂1fm^-3 and T<T₂50 MeV, these pairs Bose condense, replacing the usual 〈qq〉 condensate and restoring chiral symmetry. At high density, the ground state is a color superconductor in which diquarks play the role of Cooper pairs. An interesting toy model is provided by QCD with two colors: it has a particle-antiparticle symmetry which relates 〈qq〉 and 〈qq〉 condensates.
Rapp et al. (Mon,) studied this question.