## Abstract

We study several different kinds of bound states built from D-branes and orientifolds. These states are to atoms what branonium - the bound state of a brane and its anti-brane - is to positronium, inasmuch as they typically involve a light brane bound to a much heavier object with conserved charges which forbid the system's decay. We find the fully relativistic motion of a probe Dp′l-brane in the presence of source Dp-branes is integrable by quadratures. Keplerian conic sections are obtained for special choices for p and p′ and the systems are shown to be equivalent to non-relativistic systems. Their quantum behaviour is also equivalent to the corresponding non-relativistic limit. In particular the p = 6, p′ = 0 case is equivalent to a non-relativistic dyon in a magnetic monopole background, with trajectories in the surface of a cone. We also show that the motion of probe branes about D6-branes in IIA theory is equivalent to the motion of the corresponding probes in the uplift to M theory in 11 dimensions, for which there are no D6-branes but their fields are replaced by a particular Taub-NUT geometry. We further discuss the interactions of D-branes and orientifold planes having the same dimension. This system behaves at large distances as a brane-brane system but at shorter distances it does not have the tachyon instability.

Original language | English (US) |
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Pages (from-to) | 1729-1756 |

Number of pages | 28 |

Journal | Journal of High Energy Physics |

Volume | 8 |

Issue number | 1 |

State | Published - Jan 1 2004 |

## Keywords

- Cosmology of Theories beyond the SM
- D-branes
- Superstrings and Heterotic Strings

## ASJC Scopus subject areas

- Nuclear and High Energy Physics