Quasi-normal modes of warped black holes and warped AdS/CFT correspondence

We analytically calculate the quasi-normal modes of various perturbations of the spacelike stretched and the null warped AdS3 black holes. From AdS/CFT correspondence, these quasi-normal modes are expected to appear as the poles in momentum space of retarded Green's functions of dual operators in CFT at finite temperature. We find that this is indeed the case, after taking into account of the subtle identification of quantum numbers. The subtlety comes from the fact that only after appropriate coordinate transformation the asymptotic geometries of the warped black holes are the same as the ones of warped AdS3. We show that in general the quasi-normal modes are in good agreement with the prediction of the warped AdS/CFT correspondence, up to a constant factor. As a byproduct, we compute the conformal dimensions of the boundary operators dual to the perturbations. Our results give strong support to the conjectured warped AdS/CFT correspondence.