Conifold Transitions and Five-Brane Condensation in M-Theory on Spin(7) Manifolds
Sergei Gukov, James Sparks, David Tong
TL;DR
This work identifies and analyzes a nontrivial topology-changing transition in M-theory on Spin(7) manifolds, centered on a conifold-like singularity at the cone over $SU(3)/U(1)$. It develops a unified picture in which the transition is realized by condensation of wrapped brane states (M5 in M-theory, D6 in IIA) and is mirrored by brane/flux dualities, parity flips, and three-branch moduli tied to half-integer $G$-flux. The authors connect geometric transitions to low-energy Chern–Simons–Higgs dynamics in three dimensions, show how two distinct Type IIA dual pictures (B-picture and L-picture) encode the same physics, and provide explicit constructions of the relevant quotients and coassociative loci. The results illuminate how topology, flux quantization, and brane dynamics intertwine in reduced-supersymmetry settings, offering a first explicit example of a Spin(7) conifold transition with only 1/16 supersymmetry and broad implications for brane/flux dualities and holographic flows.
Abstract
We conjecture a topology changing transition in M-theory on a non-compact asymptotically conical Spin(7) manifold, where a 5-sphere collapses and a CP(2) bolt grows. We argue that the transition may be understood as the condensation of M5-branes wrapping the 5-sphere. Upon reduction to ten dimensions, it has a physical interpretation as a transition of D6-branes lying on calibrated submanifolds of flat space. In yet another guise, it may be seen as a geometric transition between two phases of type IIA string theory on a G_2 holonomy manifold with either wrapped D6-branes, or background Ramond-Ramond flux. This is the first non-trivial example of a topology changing transition with only 1/16 supersymmetry.
