freedom. The energy of the static $Q{\bar Q}$ or $QQQ$ systems measured with respect to the state with no sources is thus given by the Coulomb term and is determined by the expectation value of the longitudinal component of the chromo-electric field.

It is the dependence of the chromo-electric field and the Coulomb interaction on the static vector potential (through $\lambda$) that produces the differences between QCD and QED. In QED the kernel in the bracket in [Eq. (\[e\])]{} reduces to $[\cdots] \to
 \delta(\y-\z)$ and the Abelian expression for the electric field emerges. In QCD the chromo-electric field and the Coulomb potential are enhanced due to long-wavelength transverse gluon modes on the Gribov horizon where the FP operator vanishes. The combination of two effects on the Gribov horizon: enhancement of $(1 - \lambda)^{-1}$ in the longitudinal electric field and vanishing of the functional norm, which is proportional to $\det(1-\lambda)$, leads to finite, albeit large, expectation values of the static interaction between color charges. In [Eq. (\[h\])]{} we have omitted the FP measure since, as mentioned earlier in Ref. [@as4], its effect can be approximately accounted for by imposing specific boundary conditions on the ground state wave functional.

Since the chromo-electric 