D-branes in a topologically nontrivial B-field
Abstract
We study global worldsheet anomalies for open strings ending on several coincident D-branes in the presence of a B-field. We show that cancellation of anomalies is made possible by a correlation between the t'Hooft magnetic flux on the D-branes and the topological class of the B-field. One application of our results is a proper understanding of the geometric nature of the gauge field living on D-branes: rather than being a connection on a vector bundle, it is a connection on a module over a certain noncommutative algebra. Our argument works for a general closed string background. We also explain why in the presence of a topologically nontrivial B-field whose curvature is pure torsion D-branes represent classes in a twisted K-theory, as conjectured by E. Witten.
- Publication:
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arXiv e-prints
- Pub Date:
- September 1999
- DOI:
- 10.48550/arXiv.hep-th/9909089
- arXiv:
- arXiv:hep-th/9909089
- Bibcode:
- 1999hep.th....9089K
- Keywords:
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- High Energy Physics - Theory
- E-Print:
- 24 pages, latex. v2: typos corrected, notation improved