TY - JOUR
T1 - QCD at finite baryon density
T2 - Nucleon droplets and color superconductivity
AU - Alford, Mark
AU - Rajagopal, Krishna
AU - Wilczek, Frank
N1 - Funding Information:
The research of MA and FW is supported in part by DOE grant DE-FG02-90ER40542; that of KR is supported in part by DOE cooperative research agreement DE-FC02-94ER40818.
PY - 1998/3/12
Y1 - 1998/3/12
N2 - We use a variational procedure to study finite density QCD in an approximation in which the interaction between quarks is modelled by that induced by instantons. We find that uniform states with conventional chiral symmetry breaking have negative pressure with respect to empty space at all but the lowest densities, and are therefore unstable. This is a precisely defined phenomenon which motivates the basic picture of hadrons assumed in the MIT bag model, with nucleons as droplets of chiral symmetry restored phase. At all densities high enough that the chirally symmetric phase fills space, we find that color symmetry is broken by the formation of a 〈qq〉 condensate of quark Cooper pairs. A plausible ordering scheme leads to a substantial gap in a Lorentz scalar channel involving quarks of two colors, and a much smaller gap in an axial vector channel involving quarks of the third color.
AB - We use a variational procedure to study finite density QCD in an approximation in which the interaction between quarks is modelled by that induced by instantons. We find that uniform states with conventional chiral symmetry breaking have negative pressure with respect to empty space at all but the lowest densities, and are therefore unstable. This is a precisely defined phenomenon which motivates the basic picture of hadrons assumed in the MIT bag model, with nucleons as droplets of chiral symmetry restored phase. At all densities high enough that the chirally symmetric phase fills space, we find that color symmetry is broken by the formation of a 〈qq〉 condensate of quark Cooper pairs. A plausible ordering scheme leads to a substantial gap in a Lorentz scalar channel involving quarks of two colors, and a much smaller gap in an axial vector channel involving quarks of the third color.
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U2 - 10.1016/S0370-2693(98)00051-3
DO - 10.1016/S0370-2693(98)00051-3
M3 - Article
AN - SCOPUS:0040633467
SN - 0370-2693
VL - 422
SP - 247
EP - 256
JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
IS - 1-4
ER -