The Osp(8|4) singleton action from the supermembrane
Gianguido Dall'Agata, Davide Fabbri, Christophe Fraser, Pietro Fre', Piet Termonia, Mario Trigiante
TL;DR
The paper derives the $OSp(8|4)$ singleton action from the $D=11$ supermembrane on $AdS_4\times S^7$, clarifying how boundary conformal dynamics emerge from a non-linear membrane action. It employs a rheonomic, κ-fixed formulation together with a supersolvable parametrization to realize the full superconformal symmetry on the worldvolume and to organize the geometry in terms of the $OSp(8|4)$ algebra. The fluctuation analysis around a classical boundary solution yields the singleton as a free 3D conformal field on Minkowski space, with explicit bosonic and fermionic content and SUSY transformations that realize the boundary conformal symmetry. The work also lays out a framework to extract flavor-group representations for $G/H$ branes and to perform direct holographic tests beyond the maximally supersymmetric case.
Abstract
Our goal is to study the supermembrane on an $AdS_4 \times \cal M_7$ background, where $\cal M_7$ is a 7--dimensional Einstein manifold with $N$ Killing spinors. This is a direct way to derive the $Osp(N|4)$ singleton field theory with all the additional properties inherited from the geometry of the internal manifold. As a first example we consider the maximally supersymmetric $Osp(8|4)$ singleton corresponding to the choice $\cal M_7 = S^7$. We find the explicit form of the action of the membrane coupled to this background geometry and show its invariance under non--linearly realised superconformal transformations. To do this we introduce a supergroup generalisation of the solvable Lie algebra parametrisation of non--compact coset spaces. We also derive the action of quantum fluctuations around the classical configuration, showing that this is precisely the singleton action. We find that the singleton is simply realised as a free field theory living on flat Minkowski space.
