We review what has been learnt and what remains unknown about the physics of hot enhancons following studies in supergravity. We recall a rather general family of static, spherically symmetric, non-extremal enhancon solutions describing D4 branes wrapped on K3 and discuss physical aspects of the solutions. We embed these solutions in the six dimensional supergravity describing type IIA strings on K3 and generalize them to have arbitrary charge vector. This allows us to demonstrate the equivalence with a known family of hot fractional D0 brane solutions, to widen the class of solutions of this second type and to carry much of the discussion across from the D4 brane analysis. In particular we argue for the existence of a horizon branch for these branes.
The system was the first setup in which a supergravity dual of pure @math SYM theory with no hypermultiplets was studied @cite_9 . It was constructed by wrapping BPS D-branes on a K3 manifold, and studying the resulting geometry. From the supergravity point of view, the system exhibited a novel singularity resolution mechanism. Naively, there appeared to be a naked timelike singularity in the space transverse to the branes, dubbed the repulson, because a massive particle would feel a repulsive potential which becomes infinite in magnitude at a finite radius from the naive position of the branes. Probing the background with a wrapped D-brane, however, showed that the @math source D-branes do not, in fact, sit at the origin. Rather, they expand to form a shell of branes, inside of which the geometry does not, after all, become singular.
@cite_9
2040482607
We study brane configurations that give rise to large-N gauge theories with eight supersymmetries and no hypermultiplets. These configurations include a variety of wrapped, fractional, and stretched branes or strings. The corresponding spacetime geometries which we study have a distinct kind of singularity known as a repulson. We find that this singularity is removed by a distinctive mechanism, leaving a smooth geometry with a core having an enhanced gauge symmetry. The spacetime geometry can be related to large-N Seiberg-Witten theory.