Supergravity Field Theories and the Art of Constructing Them

Abstract

During the past year Lagrangian field theories in four dimensional space-time have been developed which have a new gauge principle, namely, local supersymmetry. The gauge field of supersymmetry transformation is the spin 3/2 Rarita-Schwinger field and it necessarily occurs in these theories together with the vierbein field which describes gravitation. A variety of constructions of supergravity field theories have now been given which include vector, spinor, and scalar fields. Although none of them seems to apply directly to experiment, I take the attitude that they are all interesting because they are the basic constructions associated with a gauge principle of considerable mathematical elegance. In qualitative terms, what has been achieved is an extension of general relativity in which gravitation is closely linked with the fundamental concept of anti-commuting fermion fields. Unification of lower spin fields with the graviton occurs in some models, and supergravity practitioners hope that a corresponding unification of gravitation with other particle interactions can be achieved. Since there are as yet no signals from experiment that nature is aware of our efforts, we look for theoretical signals. The improved renormalizability situation in supergravity, which will be discussed by Peter van Nieuwenhuizen at this conference, may be one such signal.