Coulomb-Gauge in QCD: Renormalization and Confinement

We review the Coulomb gauge in QCD and report some recent results. The minimal Coulomb gauge is defined and the fundamental modular region, a region without Gribov copies, is described. The Coulomb gauge action is expressed in terms of the dynamical degrees of freedom with an instantaneous Coulomb interaction, and its physical meaning is discussed. The local Coulomb gauge action with phase-space and ghost variables is derived, and its BRS-invariance and renormalizability are reviewed. It is shown that the instantaneous part V(R) of g²D₀₀(R,t), the time-time component of the gluon propagator, is a renormalization-group invariant V(R) = f (RΛ_QCD)/R, and that the contribution of V(R) to the Wilson loop exponentiates. It is conjectured that V(R) ≃ κ_coul R at large R, and that κ_coul provides an order parameter for confinement of color even in the presence of dynamical quarks.