More D-brane bound states

TL;DR

This work demonstrates a systematic, duality-based construction of low-energy D-brane bound-state solutions where the world-volume dimension difference is two, showing that supersymmetry is preserved and the configurations are BPS-saturated. By starting from tilted, delocalized D-branes and applying T-duality, the authors generate explicit bound states such as D0–D2 and extend the method to higher p-values, deriving general mass–charge relations of the form $m_{p-1,p+1}^2 = \frac{1}{2\kappa^2}\left(\tilde{q}_{p-1}^2 + q_{p+1}^2\right)$. These results complement worldsheet descriptions of bound states and highlight a versatile approach for constructing multi-brane bound states with RR-charge content dictated by the duality transformations. The findings advance understanding of non-perturbative D-brane dynamics and offer a framework for exploring bound states with various flux configurations and geometries, including potential extensions to more exotic objects and configurations.

Abstract

The low-energy background field solutions corresponding to D-brane bound states which possess a difference in dimension of two are presented. These solutions are constructed using the T-duality map between the type IIA and IIB superstring theories. Since supersymmetry is preserved by T-duality, the bound state solutions retain the supersymmetric properties of the initial (single) D-brane states from which they are produced, i.e., they preserve one half of the supersymmetries.