Supergravity celebrates quarter of a century

The first complete theory of supergravity appeared 25 years ago last autumn. To mark the occasion, the State University of New York at Stony Brook held a workshop on the subject in December. The development of supergravity 25 years ago may be thought of as the exercise of identifying a minimal set of interactions between gravitons and gravitinos that respects general co-ordinate invariance and makes supersymmetry a gauge symmetry. The task of formulating the minimal supergravity theory was accomplished by Sergio Ferrara. An important development came when 2000 terms generated by an infinitesimal supersymmetry transformation were cancelled by computer. With this result, supergravity moved from conjecture to consistency. Their approach, called the "Noether method", was based on building the correct transformation laws by retracing the reasoning of Emmy Noether's famous theorem connecting symmetries and conservation laws. Supergravity is also central to AdS/CFT correspondence, which relates supergravity in higher dimensional anti-de Sitter space-time (a space-time with constantly negative curvature) to strongly coupled gauge field theories. Theorists look forward to new and unexpected developments to be celebrated on supergravity's 50th birthday. (3 refs).