D-branes and Creation of Strings

TL;DR

This paper reviews D-brane processes involving open string creation, comparing absorption rates with gravity predictions and demonstrating conditions for string creation during brane crossings, highlighting supersymmetry protections.

Contribution

It provides a detailed comparison of open string creation processes with semiclassical gravity and establishes conditions for string creation during brane crossings, supported by supersymmetry.

Findings

Exact agreement between absorption rates and gravity calculations for threebranes.

Supersymmetry ensures the agreement persists at all orders.

Open strings can be created when p-branes cross orthogonally with force cancellation in BPS systems.

Abstract

We review two types of D-branes processes where open strings are created. In the first type, a closed string incident on a collection of D-branes is converted into a number of open strings running along them. For the case of threebranes we compare the leading absorption rate with that in semiclassical gravity, and find exact agreement. A supersymmetric non-renormalization theorem guarantees that this agreement survives all corrections in powers of the string coupling times the number of branes. The second type of process is creation of stretched open strings by crossing D-branes. We show that this is possible whenever a p-brane passes through an (8-p)-brane positioned orthogonally to it. The extra attractive force exerted by the stretched open string is crucial for finding that the net force cancels in this BPS system.