Chiral topology in the zero modes enhancement quantum model of the QCD   vacuum
  Using effective potential approach for composite operators we have formulated quantum model of the QCD vacuum. It is based on the existence and importance of the nonperturbative $q^{-4}$, topologically nontrivial excitations of the gluon field configurations there. As a result of this the QCD vacuum is found stable and it has a stationary state. The value of the scale reponsible for the nonperturbative dynamics is taken from the bounds for the pion decay constant in the chiral limit. We have obtained good numerical agreement with the phenomenological values of the topological susceptibility, the mass of $\eta'$ meson, the gluon condensate. An excellent agreement with the phenomenological values of the above mentioned quantities is achived by simply summing up our contributions and instanton-induced contributions due to Negele et al to the vacuum energy density. 
V. Gogohia