Color confinement and the quantum-chromodynamic vacuum

Abstract
The bound-state problem in QCD is studied in the modified Tamm-Dancoff formalism. The confining interaction is identified in momentum space as the vacuum expectation value of the instantaneous Coulomb interaction in the Coulomb gauge. If this vacuum expectation value is infrared singular, then color is automatically confined. All colored states have infinite energy. For color-singlet quark-antiquark and two-gluon states, the infrared singularity cancels out. The resulting finite-energy bound-state equations produce an energy spectrum comparable to that produced by a linear potential in the nonrelativistic Schrödinger equation.