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High Energy Physics - Theory, hep-th,Mathematical Physics, math-ph,Mathematics, Mathematical Physics, math.MP
Abstract:
In the first half of the paper, we study in details NS-branes, including the
NS5-brane, the Kaluza-Klein monopole and the exotic 5_2^2- or Q-brane, together
with Bianchi identities for NSNS (non)-geometric fluxes. Four-dimensional
Bianchi identities are generalized to ten dimensions with non-constant fluxes,
and get corrected by a source term in presence of an NS-brane. The latter
allows them to reduce to the expected Poisson equation. Without sources, our
Bianchi identities are also recovered by squaring a nilpotent Spin(D,D) * R+
Dirac operator. Generalized Geometry allows us in addition to express the
equations of motion explicitly in terms of fluxes. In the second half, we
perform a general analysis of ten-dimensional geometric backgrounds with
non-geometric fluxes, in the context of \beta-supergravity. We determine a
well-defined class of such vacua, that are non-geometric in standard
supergravity: they involve \beta-transforms, a manifest symmetry of
\beta-supergravity with isometries. We show as well that these vacua belong to
a geometric T-duality orbit.