Positive Energy Functional for Massless Scalars in Rotating Black Hole Backgrounds of Maximal Ungauged Supergravity. Academic Article uri icon


  • We outline a proof of the stability of a massless neutral scalar field in the background of a wide class of four dimensional asymptotically flat rotating and "electrically charged" solutions of supergravity, and the low energy limit of string theory, known as STU metrics. Despite their complexity, we find it possible to circumvent the difficulties presented by the existence of ergo regions and the related phenomenon of superradiance in the original metrics by following a strategy due to Whiting, and passing to an auxiliary metric admitting an everywhere lightlike Killing field and constructing a scalar field (related to a possible unstable mode by a nonlocal transformation) which satisfies the massless wave equation with respect to the auxiliary metric. By contrast with the case for , the associated energy density of is not only conserved but is also non-negative.

published proceedings

  • Phys Rev Lett

altmetric score

  • 1.5

author list (cited authors)

  • Cveti, M., Gibbons, G. W., Pope, C. N., & Whiting, B. F.

citation count

  • 4

complete list of authors

  • Cveti─Ź, M||Gibbons, GW||Pope, CN||Whiting, BF

publication date

  • June 2020