  At the leading order, M-theory admits minimal supersymmetric
compactifications if the internal manifold has exceptional holonomy. Once we
take into account higher order quantum correction terms in the low energy
effective action, the supergravity vacua have to be deformed away from the
exceptional holonomy if we want to preserve the supersymmetry of the solution.
In this paper we discuss the Spin(7) holonomy case. We derive a perturbative
set of solutions which emerges from a warped compactification with
non-vanishing flux for the M-theory field strength and we identify the
supersymmetric vacua out of this general set of solutions. For this purpose we
have to evaluate the value of the quartic polynomial J0 on a Spin(7) holonomy
manifold as well as its first variation with respect to the internal metric. We
show that in general the Ricci flatness of the internal manifold is lost.

High Energy Physics - Theory