About the stability of a D4 - anti D 4 system

TL;DR

This paper investigates the stability of a D4-anti D4 brane system with magnetic fields, confirming supersymmetry preservation and stability conditions through spectrum analysis and interaction amplitude calculations.

Contribution

It provides a detailed analysis of the stability conditions for D4-anti D4 branes with magnetic fields, aligning low-energy effective theory results with string theory spectrum conditions.

Findings

Absence of tachyons coincides with supersymmetry preservation conditions.

Interaction amplitude calculations verify no-force and stability.

System preserves 1/4 of the supersymmetry in Type IIA string theory.

Abstract

We study a system of coincident $D4$ and $\bar D 4$ branes with non zero world-volume magnetic fields in the weak coupling limit. We show that the conditions for absence of tachyons in the spectrum coincide exactly with those found in hep-th/0206041, in the low energy effective theory approach, for the system to preserve a $\frac 14$ of the supersymmetries of the Type IIA string theory vacuum. We present further evidence about the stability of the system by computing the lowest order interaction amplitude from both open and closed channels, thus verifying the no force condition as well as the supersymmetric character of the spectrum. A brief discussion of the low energy effective five dimensional world-volume theory is given.