GAUGE-FIELDS AS COMPOSITE BOUNDARY EXCITATIONS

We investigate representations of the conformal group that describe '' massless'' particles in the interior and at the boundary of anti-de Si tter space. It turns out that massless gauge excitations in anti-de Si tter are gauge ''current'' operators at the boundary. Conversely, mass less excitations at the boundary are topological singletons in the int erior. These representations lie at the threshold of two ''unitary bou nds'' that apply to any conformally invariant field theory. Gravity an d Yang-Mills gauge symmetry in anti-De Sitter is translated to global translational symmetry and continuous R-symmetry of the boundary super conformal field theory. (C) 1998 Elsevier Science B.V. All rights rese rved.