Tri-Sasakian consistent reduction
Davide Cassani, Paul Koerber
TL;DR
This work constructs a universal consistent Kaluza–Klein truncation of M-theory on seven-dimensional tri-Sasakian manifolds, yielding a four-dimensional $ mathcal{N}=4$ gauged supergravity with three vector multiplets and an $SO(3)$ gauge factor. Consistency is established by mapping the reduction to a left-invariant coset reduction on $Sp(2)/Sp(1)$ and embedding the result into the $ ext{E}_{7(7)}$ framework via Exceptional Generalized Geometry; it also connects to the coset realizations of other universal truncations. The resulting theory admits AdS$_4$ vacua with spontaneous $ math{4} o math{3,1,0}$ supersymmetry breaking and a spectrum containing massive modes, including subtruncations to minimal $ math{N}=3$ and $ math{N}=1$ sectors, as well as an enhanced truncation on $N^{010}$ with a Betti vector multiplet. The construction has implications for AdS$_4$/CFT$_3$ holography and holographic condensed matter, illustrating a unified, universal framework for consistent truncations across multiple compactification manifolds.
Abstract
We establish a universal consistent Kaluza-Klein truncation of M-theory based on seven-dimensional tri-Sasakian structure. The four-dimensional truncated theory is an N=4 gauged supergravity with three vector multiplets and a non-abelian gauge group, containing the compact factor SO(3). Consistency follows from the fact that our truncation takes exactly the same form as a left-invariant reduction on a specific coset manifold, and we show that the same holds for the various universal consistent truncations recently put forward in the literature. We describe how the global symmetry group SL(2,R) x SO(6,3) is embedded in the symmetry group E7(7) of maximally supersymmetric reductions, and make the connection with the approach of Exceptional Generalized Geometry. Vacuum AdS4 solutions spontaneously break the amount of supersymmetry from N=4 to N=3,1 or 0, and the spectrum contains massive modes. We find a subtruncation to minimal N=3 gauged supergravity as well as an N=1 subtruncation to the SO(3)-invariant sector. We also show that a reduction on the homogeneous space N^{010} enhances the universal tri-Sasakian truncation with a Betti vector multiplet.
