Mass Spectrum of D=11 Supergravity on $AdS_{2}\times S^{2} \times T^{7}$

We compute the Kaluza-Klein mass spectrum of the D=11 supergravity compactified on AdS_2\times S^2\times T^7 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 T^7. 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