D-Branes, RR-Fields and duality on noncommutative manifolds, by Jacek Brodzki, Varghese Mathai, Jonathan Rosenberg, and Richard J. Szabo

We develop some of the ingredients needed for string theory on noncommutative spacetimes, proposing an axiomatic formulation of T-duality as well as establishing a very general formula for D-brane charges. This formula is closely related to a noncommutative Grothendieck-Riemann-Roch theorem that is proved here. Our approach relies on a very general form of Poincaré duality, which is studied here in detail. Among the technical tools employed are calculations with iterated products in bivariant K-theory and cyclic theory, which are simplified using a novel diagram calculus reminiscent of Feynman diagrams.

Jacek Brodzki <j.brodzki@soton.ac.uk>
Varghese Mathai <vmathai@maths.adelaide.edu.au>
Jonathan Rosenberg <jmr@math.umd.edu>
Richard J. Szabo <R.J.Szabo@ma.hw.ac.uk>