ABSTRACT

The gravitational interaction plays the most important role in the evolution of the universe although this is the weakest of all the forces. However, at very high energies gravity should become as strong as any other interaction. Since the strong, the weak and the electromagnetic interactions are gauge theories and could be unied in a grand unied theory, we envisage an ultimate theory at higher energies in which gravity will be unied with all other interactions. At higher energies we expect our theory to be supersymmetric to solve the gauge hierarchy problem and allow unication of Poincar·e group with the internal symmetry groups. So, we must also formulate a supersymmetric theory of gravity, which is the supergravity.