Abstract
We show that the six-dimensional uplift of the five-dimensional
Near-Horizon-Extremal-Kerr (NHEK) spacetime can be obtained from an AdS\_3 X S^3
solution by a sequence of supergravity - but not string theory - dualities. We
present three ways of viewing these pseudo-dualities: as a series of
transformations in the STU model, as a combination of Melvin twists and
T-dualities and, finally, as a sequence of two generalized spectral flows and a
coordinate transformation. We then use these to find an infinite family of
asymptotically flat embeddings of NHEK spacetimes in string theory,
parameterized by the arbitrary values of the moduli at infinity. Our
construction reveals the existence of non-perturbative deformations of
asymptotically-NHEK spacetimes, which correspond to the bubbling of nontrivial
cycles wrapped by flux, and paves the way for finding a microscopic field
theory dual to NHEK which involves Melvin twists of the D1-D5 gauge theory. Our
analysis also clarifies the meaning of the generalized spectral flow
solution-generating techniques that have been recently employed in the
literature.
