The spontaneous breakdown of chiral symmetry in the semiclassical method. Pt. 1

It is suggested that the usual path integral representation of the euclidean vacuum amplitude in QCD must be supplemented by the explicit boundary condition corresponding to the spontaneous breaking of chiral SU(N) x SU(N). The analogy with the quantum mechanical example naturally leads to the trial wave function of Nambu and Jona-Lasinio and this in turn gives the starting point for self-consistent calculation. (orig.)