Intersecting Flavor Branes

TL;DR

This paper studies the instability caused by open string tachyons in a specific AdS/CFT setup with intersecting D7 branes, linking bulk tachyon dynamics to boundary field theory operators.

Contribution

It provides a detailed analysis of tachyon-induced instability in a brane intersection model and predicts tachyon mass via AdS/CFT correspondence.

Findings

Identifies a mesonic operator dual to the open string tachyon.

Predicts tachyon mass that violates the AdS stability bound at small 't Hooft coupling.

Establishes a connection between bulk tachyon instability and boundary field theory potential.

Abstract

We consider an instance of the AdS/CFT duality where the bulk theory contains an open string tachyon, and study the instability from the viewpoint of the boundary field theory. We focus on the specific example of the AdS_5 X S^5 background with two probe D7 branes intersecting at general angles. For generic angles supersymmetry is completely broken and there is an open string tachyon between the branes. The field theory action for this system is obtained by coupling to N =4 super Yang-Mills two N =2 hyper multiplets in the fundamental representation of the SU(N) gauge group, but with different choices of embedding of the two N=2 subalgebras into N=4. On the field theory side we find a one-loop Coleman-Weinberg instability in the effective potential for the fundamental scalars. We identify a mesonic operator as the dual of the open string tachyon. By AdS/CFT, we predict the tachyon mass for small 't Hooft coupling (large bulk curvature) and confirm that it violates the AdS stability bound.