Instanton effects in the quark plasma

Here the authors try to extend the discussion of the quark plasma to include non-perturbative effects caused by instantons. Before discussing the more technically involved QCD problem, they treat the Abelian-Higgs model in two dimensions in the presence of massless fermions. The general physical picture which will emerge in this simplified model is probably not too distant from the one in QCD, however, the latter is far from being well understood. After a brief account of the path integral formalism used, they discuss the Higgs model and then go on to describe what has been accomplished in QCD. (Auth.)