# On D-brane dynamics and moduli stabilization

## TL;DR

This paper examines how D-brane dynamics influence moduli stabilization in type IIB string theory, highlighting complex interactions that can both aid and hinder the stabilization process in specific compactification models.

## Contribution

It provides a detailed analysis of D-brane and anti-D-brane interactions in a concrete T6/Z3 orientifold model, exploring their impact on moduli stabilization and supersymmetry breaking.

## Key findings

- D-brane interactions can both stabilize and destabilize Kahler moduli.
- Anti-D3-branes create attractive forces affecting compactification stability.
- Brane interactions sometimes assist but do not always facilitate moduli stabilization.

## Abstract

We discuss the effect of the dynamics of D-branes on moduli stabilization in type IIB string theory compactifications, with reference to a concrete toy model of T6/Z3 orientifold compactification with fractional D3-branes and anti-D3-branes at orbifold fixed points. The resulting attractive forces between anti-D3-branes and D3-branes, together with the repulsive forces between anti-D3-branes and O3-planes, can affect the stability of the compact space. There are no complex structure moduli in T6/Z3 orientifold, which should thus capture some generic features of more general settings where all complex structure moduli are stabilized by three-form fluxes. The simultaneous presence of branes and anti-branes brings along the breaking of supersymmetry. Non-BPS combinations of this type are typical of "brane supersymmetry breaking", and are a necessary ingredient in the KKLT scenario for stabilizing the remaining Kahler moduli. The conclusion of our analysis is that, while mutual D-brane interactions sometimes help Kahler moduli stabilization, this is not always the case.