QCD at finite baryon density: nucleon droplets and color superconductivity

摘要: Abstract We use a variational procedure to study finite density QCD in an approximation which the interaction between quarks is modelled by that induced instantons. find uniform states with conventional chiral symmetry breaking have negative pressure respect empty space at all but lowest densities, and are therefore unstable. This precisely defined phenomenon motivates basic picture of hadrons assumed MIT bag model, nucleons as droplets restored phase. At densities high enough chirally symmetric phase fills space, we color broken formation 〈 qq 〉 condensate quark Cooper pairs. A plausible ordering scheme leads substantial gap Lorentz scalar channel involving two colors, much smaller axial vector third color.