Ramond-Ramond couplings of D-branes

TL;DR

This paper derives a comprehensive formula for D-brane Ramond-Ramond couplings using supersymmetric localization, incorporating all massive open string modes, and confirms certain brane creation processes are forbidden.

Contribution

It provides the most general RR coupling formula for D-branes including massive modes, expressed via Quillen's superconnection, and verifies charge quantization and brane creation constraints.

Findings

The formula includes higher form gauge fields and is consistent with RR charge quantization.

Massive open string modes contribute finitely to the RR coupling.

D9-brane creation via massive mode condensation is shown to be impossible.

Abstract

Applying supersymmetric localization for superstring worldsheet theory with N=(1,1) supersymmetries on a cylinder and with arbitrary boundary interactions, we find the most general formula for the Ramond-Ramond (RR) coupling of D-branes. We allow all massive excitations of open superstrings, and find that only a finite number of them can contribute to the formula. The formula is written by Quillen's superconnection which includes higher form gauge fields, and the resultant general Chern-Simons terms are consistent with RR charge quantization. Applying the formula to boundary string field theory of a BPS D9-brane or a D9-antiD9 brane system, we find that any D9-brane creation via massive mode condensation is impossible.