Non-supersymmetric D-Brane Configurations with Bose-Fermi Degenerate Open String Spectrum

TL;DR

This paper investigates non-BPS D-brane configurations in type II string theory on a K3 orbifold, revealing specific moduli where open string spectra become bose-fermi degenerate, leading to vanishing closed string interactions.

Contribution

It identifies conditions under which non-BPS D-branes exhibit bose-fermi degeneracy in their open string spectra, a novel finding in string theory.

Findings

Degeneracy occurs at specific moduli values.

Vanishing closed string interactions at these points.

Spectrum analysis on K3 orbifold.

Abstract

The spectrum of open strings on various non-BPS D-brane configurations in type II string theory on a K3 orbifold is analysed. At a generic point in the corresponding moduli space the spectrum of open strings does not have any degeneracy between bosonic and fermionic states. However, there exist special values for these moduli for which many non-BPS D-brane configurations have an exactly bose-fermi degenerate open string spectrum at all mass levels. In this case the closed string exchange interaction between a pair of such D-brane configurations vanishes at all distances.