Adjoint ''quarks'' and the physics of confinement

The quark-antiquark potential and the chromoelectric fields generated by ''quarks'' in the adjoint representation of four-dimensional SU(2) color are analyzed in the scaling region of the theory. New results with interesting implications for our understanding of the confinement mechanism are presented. In particular, the formation of color-electric flux-tubes between adjoint quarks is demonstrated. The flux-tubes for fundamental and adjoint representation quarks are shown to have very similar cross-sections. This result could imply that the QCD vacuum is dual to a type I superconductor.