Schreiber Brane Charge in Unstable K-Theory

An article that we are finalizing:

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• Pinak Banerjee, Hisham Sati and Urs Schreiber:

  
  

  D/NS-Brane Charge in Unstable K-Theory

  draft: pdf

  
  

  The traditional conjecture that D-brane charge is quantized in stable K-cohomology fails to account for the presence of NS-brane sources: These impose nonlinear relations — reductions of the famous quadratic relation on M-brane flux — that can only be captured by unstable nonabelian cohomology theories. Here we consider a deformation of unstable K-theory which properly quantizes the fluxes coupling to D0/D2/NS5-branes, find a twisted version that quantizes also the fluxes coupling to NS1/D4-branes, and show that this oxidizes to a proper electromagnetic quantization of M-brane fluxes.

Based on:

• Rational sphere valued supercocycles in M-theory

• Flux Quantization