Stationary BPS solutions to dilaton-axion gravity
Stationary BPS solutions to dilaton-axion gravity
Stationary four-dimensional BPS solutions to gravity-coupled bosonic theories admitting a three-dimensional $\ensuremath{\sigma}$-model representation on coset spaces are interpreted as null geodesics of the target manifold equipped with a certain number of harmonic maps. For asymptotically flat (or Taub-NUT) space-times such geodesics can be directly parametrized in terms of charges saturating …