Branes, Orientifolds and the Creation of Elementary Strings

TL;DR

This work analyzes configurations of two D-branes with $ND=8$, demonstrating that a fundamental string is created when the branes cross and that the inter-brane force receives a nontrivial RR contribution despite the absence of net RR charge. The authors show that the D0-D8 system probes massive IIA supergravity, requiring string endpoints on D0-branes and linking to a Hanany-Witten-type effect through dualities. They extend the analysis to D0 on an $\Omega 8$-plane (Type IA) and derive velocity-dependent potentials, finding divergences tied to RR$(-1)^F$ sectors that vanish under certain background conditions. The paper also develops world-line and matrix-model descriptions, highlighting how ten-dimensional dynamics persist in certain massive backgrounds and illuminating connections to heterotic dualities and anomaly inflow in matrix theory contexts.

Abstract

The potential of a configuration of two Dirichlet branes for which the number of ND-directions is eight is determined. Depending on whether one of the branes is an anti-brane or a brane, the potential vanishes or is twice as large as the dilaton-gravitational potential. This is shown to be related to the fact that a fundamental string is created when two such branes cross. Special emphasis is given to the D0-D8 system, for which an interpretation of these results in terms of the massive IIA supergravity is presented. It is also shown that the branes cannot move non-adiabatically in the transverse direction. The configuration of a zero brane and an orientifold 8-plane is analyzed in a similar way, and some implications for the type IA-heterotic duality and the heterotic matrix theory are discussed.

Figures (4)

• Figure 1: A D$p$-brane crossing a D$(8-p)$-brane.
• Figure 2: A D0-brane crossing a D8-brane. The dashed line represents a half-string. The value of $m$ is given in units of $\mu_8$.
• Figure 3: A D0-brane crossing two D8-branes.
• Figure 4: D0-brane and image in the presence of (a) an $\Omega 8$-plane and (b) an $\overline{\Omega 8}$-plane.