Monopole condensation and confinement

To understand the mechanism of the confinement is important in order to explain hadron physics out of QCD. The 'tHooft idea of abelian projection of QCD is interesting. After the abelian projection, QCD can be regarded as an abelian theory with electric charges and monopoles. If the monopoles make Bose condensation, charged quarks and gluons are confined due to the dual Meissner effect. Performing Monte-Carlo simulations, we have tested whether the conjecture is true or not at least on lattices. Our results in 1995 were reported in five articles such as Block spin transformation on the dual lattice and monopole action, monopoles and hadron spectrum in quenched QCD; Study of gauge (in)dependence of monopole dynamics and monopoles in high temperature phase of SU(2) QCD. These reports are explained in detail. (S.Y.)