The N=2 cascade revisited and the enhancon bearings

TL;DR

This paper revisits the N=2 cascade in supergravity backgrounds, providing a precise dual field theory interpretation, exploring Coulomb branch vacua, and introducing new geometric structures called enhancon bearings.

Contribution

It offers a detailed dual field theory interpretation of supergravity cascades and introduces the concept of enhancon bearings as new geometric structures in the holographic context.

Findings

Identified the Coulomb branch vacuum corresponding to the known cascade.

Proposed a modified cascade flow leading to the Klebanov-Strassler solution.

Constructed explicit, repulson-free supergravity backgrounds for various vacua.

Abstract

Supergravity backgrounds with varying fluxes generated by fractional branes at non-isolated Calabi-Yau singularities had escaped a precise dual field theory interpretation so far. In the present work, considering the prototypical example of such models, the C*C^2/Z_2 orbifold, we propose a solution for this problem, and show that the known cascading solution corresponds to a vacuum on the Coulomb branch of the corresponding quiver gauge theory involving a sequence of strong coupling transitions reminiscent of the baryonic root of N=2 SQCD. We also find a slight modification of this cascading vacuum which upon mass deformation is expected to flow to the Klebanov-Strassler cascade. Finally, we discuss an infinite class of vacua on the Coulomb branch whose RG flows include infinitely coupled conformal regimes, and explain their gravitational manifestation in terms of new geometric structures that we dub enhancon bearings. Repulson-free backgrounds dual to all the vacua we analyse are explicitly provided.