Mass Spectrum of D=11 Supergravity on AdS2 x S2 x T7

Abstract

We compute the Kaluza-Klein mass spectrum of the D=11 supergravity compactified on AdS2 x S2 x T7 and arrange it into representations of the SU(1,1|2) superconformal algebra. This geometry arises in M theory as the near horizon limit of a D=4 extremal black-hole constructed by wrapping four groups of M-branes along the T7. Via AdS/CFT correspondence, our result gives a prediction for the spectrum of the chiral primary operators in the dual conformal quantum mechanics yet to be formulated.Comment: 30 pages, 2 figures; v3. more careful treatments of the boundary modes, and other minor correction