Magnons in a Model with Antiferromagnetic Properties. — II

Summary

The analysis of the model studied in I is continued with. the intention to clarify two problems: the compatibility of the results concerning the magnons (angular momentum zero around the axis) with the requirements of the Goldstone theorem, and the existence of « strange » electrons of spin zero. With regard to the first problem the results of a conventional perturbation theory are compared with the results of the Tamm-Dancoff method; the comparison leads to a better understanding of the dynamics of the magnon vibrations and of their rôle in the Goldstone theorem. Strange electrons of spin zero are a natural consequence of the model and may be compared with, e.g., the singlet states in the optical spectrum of Ca. The rôle of the corresponding states in elementary-particle physics is discussed, especially in connection with an approximate SU ₃ behaviour in the spectrum.