STABILITY OF THE VACUUM AND DIELECTRIC MODEL OF CONFINEMENT IN QCD

After the gauge invariant gluon condensation, gluons remain as massless excitations. When the effective theory describing the condensation and the excitation is constructed, a constraint has to be imposed for the vacuum to be stable. The constraint implies the perfect dia-electricity and assures the solution of color flux tube when quarks are introduced. Thus the dia-electric model of Kogut–Susskind and 't Hooft is derived by the stability of the condensed vacuum.