Gerbes and Massive Type II Configurations

TL;DR

This paper introduces new bound states involving NS5, D6, and D8-branes in massive Type IIA string theory, using gerbes to describe nonlocal configurations and developing a global formalism for massive tensor fields.

Contribution

It develops a formalism for massive tensor fields in supergravity and applies it to describe novel brane configurations involving gerbes in massive Type IIA.

Findings

Identification of novel NS5/D6/D8-brane bound states

Development of a global formalism for massive tensor fields

Insights into brane charge classification and F-theory relations

Abstract

We find novel bound states of NS5, D6 and D8-branes in massive Type IIA string theory. As the NS gauge transformations can change the Chern class of the RR field these configurations should be thought of as nonlocal objects called gerbes. We develop a global formalism for theories that involve massive tensor fields in general, and apply it in massive Type IIA supergravity. We check the results by investigating the T-dual NS5/D5-brane configurations in Type IIB, and relate them to an F-theory compactification on a CY3. We comment on the implications to consistency conditions for brane-wrapping and the classification of D-brane charges in terms of K-theory classes.