Creation of Fundamental Strings by Crossing D-branes

TL;DR

This paper investigates the phenomenon of fundamental string creation during D-brane crossings, revealing a force balance mechanism involving string stretching and connecting branes, with implications for M-theory and string dualities.

Contribution

It provides a detailed analysis of string creation during D-brane crossings using Chern-Simons terms and links this process to M-theory brane interactions and U-duality.

Findings

Fundamental strings are created when p-branes pass through (8-p)-branes.

The string creation process is explained via Chern-Simons terms in D-brane actions.

The phenomenon is related to M2-brane creation in M-theory.

Abstract

We study the force balance between orthogonally positioned $p$-brane and $(8-p)$-brane. The force due to graviton and dilaton exchange is repulsive in this case. We identify the attractive force that balances this repulsion as due to one-half of a fundamental string stretched between the branes. As the $p$-brane passes through the $(8-p)$-brane, the connecting string changes direction, which may be interpreted as creation of one fundamental string. We show this directly from the structure of the Chern-Simons terms in the D-brane effective actions. We also discuss the effect of string creation on the 0-brane quantum mechanics in the type I' theory. The creation of a fundamental string is related by U-duality to the creation of a 3-brane discussed by Hanany and Witten. Both processes have a common origin in M-theory: as two M5-branes with one common direction cross, a M2-brane stretched between them is created.