  The purpose of this study is to investigate the relations between instantons,
monopoles, and Chiral symmetry breaking. The monopoles are important
topological configurations existing in QCD which are believed to produce colour
confinement. The groups of University of Kanazawa and Pisa have produced by
Lattice simulations many results supporting the idea that QCD vacuum is a dual
superconductor. Instantons are related to Chiral symmetry breaking, as
explained e.g. in the instanton liquid model of E. V. SHURYAK. Clarifying
quantitatively the relation between monopoles and instantons is not easy, also
because monopoles are three dimensional objects, while instantons are four
dimensional. We generate configurations, adding monopole-antimonopole pairs of
opposite charges by a monopole creation operator. We observe that the monopole
creation operator only adds long monopole loops in the configurations. Then, we
count the number of fermion zero modes in the configurations using Overlap
fermions as a tool. Finally, we find that one monopole-antimonopole pair makes
one zero mode of plus or minus chirality, that is to say, one instanton of plus
or minus charge.
