Partial supersymmetry breaking and AdS4 supermembrane

We consider partial spontaneous breaking of N = I AdS(4) supersymmetry OSp(1/4) down to N = 1, d = 3 Poincare supersymmetry in the nonlinear realizations framework. We construct the corresponding worldvolume Goldstone superfield action and show that it describes the N = I AdS(4) supermembrane. It enjoys OSp(1/4) supersymmetry realized as a field-dependent modification of N = 1, d = 3 superconformal symmetry and goes into the superfield action of ordinary N = 1, D = 4 supermembrane in the flat limit. Its bosonic core is the Maldacena-type conformally invariant action of the AdS(4) membrane. We show how to reproduce the latter action within a nonlinear realization of the AdS(4) group SO(2, 3). The same universal nonlinear realizations techniques can be used to construct conformally-invariant worldvolume actions for (D - 2)-branes in generic AdS(D) spaces. (C) 2002 Published by Elsevier Science B.V.