Non-abelian gauge theories and quark confinement

Abstract

After some philosophical remarks concerning the development of theoretical physics in this century a short introduction to non-Abelian gauge theory is given. If we concentrate on the case where the local gauge group is SU(N) we find that gauge-invariant definitions can be given of the concepts of electric and magnetic flux. Both are quantized and conserved modulo N. Either the electric or the magnetic flux must be squeezed in narrow flux tubes called vortices or strings. If the vortices are electric then quarks are confined into grouplets of multiples of N quarks. A phase transition, separates the ''quark confinement mode'' from the ''Higgs mode'', the latter being easier accessible by the use of perturbation expansion.