N=4 gauged supergravity and a IIB orientifold with fluxes

TL;DR

This work analyzes a four-dimensional $N=4$ gauged supergravity, obtained by gauging translational isometries of the scalar manifold, as an effective description of the super-Higgs phases in Type-IIB orientifold compactifications with 3-form fluxes. It employs a dual, $GL(6,\mathbb{R})\times SL(2,\mathbb{R})$-covariant formulation to gauge a flat subgroup, derives the fermion shifts and the scalar potential, and shows the potential is semidefinite nonnegative with a Minkowski minimum when $F^{-IJK}=0$, revealing a no-scale structure. The paper computes the gravitino and vector spectra in the extremum, clarifies how the $N=4\to N=3,2,1,0$ breakings arise from flux components, and identifies the corresponding moduli spaces for each residual supersymmetry. It also connects these results to string compactifications with fluxes and discusses how adding D3-branes or comparing to Scherk–Schwarz reductions would modify the matter content and moduli while preserving the no-scale framework.

Abstract

We analyze the properties of a spontaneously broken D=4, N=4 supergravity without cosmological constant, obtained by gauging translational isometries of its classical scalar manifold. This theory offers a suitable low energy description of the super-Higgs phases of certain Type-IIB orientifold compactifications with 3-form fluxes turned on. We study its N=3,2,1,0 phases and their classical moduli spaces and we show that this theory is an example of no-scale extended supergravity.