The Scherk-Schwarz mechanism as a flux compactification with internal torsion

The aim of this paper is to make progress in the understanding of theScherk-Schwarz dimensional reduction in terms of a compactification in thepresence of background fluxes and torsion. From the eleven dimensionalsupergravity point of view, we find that a general E6(6) S-S phase may beobtained by turning on an appropriate background torsion, together withsuitable fluxes, some of which can be directly identified with certaincomponents of the four-form field-strength. Furthermore, we introduce a novel(four dimensional) approach to the study of dualities between flux/torsioncompactifications of Type II/M-theory. This approach defines the action thatduality should have on the background quantities, in order for the E7(7)invariance of the field equations and Bianchi identities to be restored also inthe presence of fluxes/torsion. This analysis further implies theinterpretation of the torsion flux as the T-dual of the NS three-form flux.Comment: Version published on J. High Energy Phy