LAGRANGIAN FIELD THEORY IN TERMS OF GREENS FUNCTIONS .2. THEORY OF SELF-GENERATING INTERACTIONS

A set of independent variables, called stripped correlation functions, closely related to Green's functions, are introduced to characterize a given field theory. The parameters of the theory, which describe the interaction between fields (interaction potentials), are expressed in terms of these variables. The equations obtained by putting all the interaction potentials equal to zero are shown to be derivable from a stationarity principle on vacuum fluctuations with respect to stripped correlation functions. The resulting theory of self-generating interactions is discussed and it is shown that in such a theory single-particle propagators are not renormalized. These results are examined in connection with «bootstrap» theories and with a «quark» model of elementary particles. © 1968 Società Italiana di Fisica.