Half-BPS quotients in M-theory: ADE with a twist

Paul de Medeiros, José Figueroa-O'Farrill, Sunil Gadhia, Elena Méndez-Escobar
2009 Journal of High Energy Physics  
We classify Freund-Rubin backgrounds of eleven-dimensional supergravity of the form AdS_4 x X^7 which are at least half BPS; equivalently, smooth quotients of the round 7-sphere by finite subgroups of SO(8) which admit an (N>3)-dimensional subspace of Killing spinors. The classification is given in terms of pairs consisting of an ADE subgroup of SU(2) and an automorphism defining its embedding in SO(8). In particular we find novel half-BPS quotients associated with the subgroups of type D_n
more » ... ups of type D_n (for n>5), E_7 and E_8 and their outer automorphisms.
doi:10.1088/1126-6708/2009/10/038 fatcat:f5srm73v5fbcpbyhia2b2gfavu