On the Problem of Unitarization in Field Theories With Indefinite Metric

摘要

I do want to(consider in these lectures theories in which the indefinite metric and the unitarization is more closely connected with the particular dynamics. As major examples we have q.e.d. and the Heisenberg Lee model, and mass-less quantum field theories of higher spin or with interior degrees of freedom (massless Yang-Kills theories). We will find that all these theories have a particular ghost structure which may or, in some cases, do enable their unitarization.