Calculation of the green functions by the coupling constant dispersion relations
Abstract
The discontinuities of the Green functions on the cut in the complex plane of the coupling constant are calculated by the steepest descent method. The saddle points are given by the solutions of the classical field equations at those values of the coupling constant for which the classical theory has no ground state. The Green functions at the physical values of the coupling constant are determined by dispersion relations.
 Publication:

Physics Letters B
 Pub Date:
 March 1977
 DOI:
 10.1016/03702693(77)901010
 Bibcode:
 1977PhLB...67..193B