J. Kellendonk, H. Schulz-Baldes
Boundary maps for C*-crossed products with R 
with an application to the quantum Hall effect
(587K, postscript)

ABSTRACT.  The boundary map in K-theory arising from the Wiener-Hopf extension 
of a crossed product algebra with $\RR$ is the Connes-Thom 
isomorphism. In this article, the Wiener Hopf extension is combined 
with the Heisenberg group algebra to provide an elementary 
construction of a corresponding map in cyclic cohomology. It then 
follows directly from a non-commutative Stokes theorem that this map 
is dual w.r.t. Connes' pairing of cyclic cohomology with K-theory. 
As an application, we prove equality of quantized bulk and edge 
conductivities for the integer quantum Hall effect described by 
continuous magnetic Schrodinger operators.