MAGNETIC MONOPOLE LOOP FOR THE YANG-MILLS INSTANTON

We investigate 't Hooft-Mandelstam monopoles in QCD in the presence of a single classical instanton configuration. The solution to the maxim al Abelian projection is found to be a circular monopole trajectory wi th radius R centered on the instanton. At zero loop radius, there is a marginally stable (or flat) direction for loop formation to O(R(4)lnR ). We argue that loops will form, in the semiclassical limit, due to s mall perturbations such as the dipole interaction between instanton-an ti-instanton pairs. As the instanton gas becomes a liquid, the percola tion of the monopole loops may, therefore, provide a semiclassical pre cursor to the confinement mechanism.