A proposal is presented for simulating an improvement on quenched QCD with dynamical fermions which interact with the gluon configuration only via the topological index of the latter. The strengths and shortcomings of the method are discussed and it is argued that the approximation—though crude—shares some qualitative aspects of full QCD which relate to the issue of chiral symmetry breaking.

• Received 2 November 1998

DOI:https://doi.org/10.1103/PhysRevD.59.094501