A self-consistent treatment of non-linear effects in a model quark-antiquark-gluon system

After presenting a formalism that is suitable for treating non-linear effects in a quantum setting, we analyse a model quark-antiquark-gluon system. This model is a truncated version of the full QCD Coulomb gauge hamiltonian in the heavy quark mass limit. Using a variational approximation, we show that the quark-antiquark-gluon singlet state becomes lower in energy than the pure quark-antiquark singlet for moderate values of the strong coupling constant, thus becoming the ground state of the system. (orig.)