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.

24 pages, latex. v2: typos corrected, notation improved

Cited by in corpus (11)

• Noncommutative Tachyons and K-Theory
• Boundary Fixed Points, Enhanced Gauge Symmetry and Singular Bundles on K3
• What Does(n't) K-theory Classify?
• Discrete Torsion, Non-Abelian Orbifolds and the Schur Multiplier
• Mirror symmetry and deformation quantization
• Twisted K-homology theory, twisted Ext-theory
• IIB Soliton Spectra with All Fluxes Activated
• The Cascade is a MMS Instanton
• On Algebraic Singularities, Finite Graphs and D-Brane Gauge Theories: A String Theoretic Perspective
• Non-Abelian Gerbes from Strings on a Branched Space-Time
• D-branes and twisted K-theory