Why are fractional charges of orientifolds compatible with Dirac quantization?

Orientifold $p$-planes with $p\le4$ have fractional D$p$-charges, and therefore appear inconsistent with Dirac quantization with respect to D$(6-p)$-branes. We explain in detail how this issue is resolved by taking into account the anomaly of the worldvolume fermions using the $\eta$ invariants....

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Bibliographic Details
Main Author: Yuji Tachikawa, Kazuya Yonekura
Format: Article
Language:English
Published: SciPost 2019-11-01
Series:SciPost Physics
Online Access:https://scipost.org/SciPostPhys.7.5.058