Monopoles and Grand Unification
The study of magnetic monopoles may be divided into four eras. In the first, monopoles were unobserved objects whose existence was merely an interesting possibility. The second period began in 1931 with Dirac’s1 observation that the existence of a magnetic monopole would explain the observed quantization of electric charge. A third era was entered when it was realized that electric charge is naturally quantized in unified theories, where electromagnetism is imbedded in a spontaneously broken gauge theory based on a compact semi-simple group; monopoles did not appear to be needed. Finally, a fourth era began in 1974 with the realization2 that such unified theories imply the existence of magnetic monopoles and that these monopoles have calculable properties. Before proceeding further, it may be useful to recall why, aside from the question of monopoles, certain of these unified theories have come to be of particular interest.
KeywordsSymmetry Breaking Magnetic Charge Topological Charge Homotopy Group Proton Decay
Unable to display preview. Download preview PDF.
- S. Coleman, “The Magnetic Monopole Fifty Years Later,” in The Unity of the Fundamental Interactions, ed., A. Zichichi, (Plenum, 1983).Google Scholar
- 12.S. Coleman, “Classical Lumps and Their Quantum Descendents,” in New Phenomena in Subnuclear Physics, ed., A. Zichichi, (Plenum, 1977).Google Scholar
- P. Eckert, D. Altschüler, T. Schücker, and G. Wanner, Univ. of Geneva preprint UGVA-DPT 1983/03-383 (1983).Google Scholar
- P. Eckert, D. Altschüler, and T. Schucker, Univ. of Geneva preprint UGVA-DPT 1983/07-402 (1983).Google Scholar
- 18.C. Gardner and J. Harvey, Princeton University preprint (1983).Google Scholar
- E. Weinberg, D. London, and J. Rosner, Univ. of Chicago preprint EFI83-39 (1983).Google Scholar