A Bivariant Chern Character¶for Families of Spectral Triples

In this paper we construct a bivariant Chern character defined on “families of spectral triples”. Such families should be viewed as a version of unbounded Kasparov bimodules adapted to the category of bornological algebras. The Chern character then takes its values in the bivariant entire cyclic cohomology of Meyer. The basic idea is to work within Quillen's algebra cochains formalism, and construct the Chern character from the exponential of the curvature of a superconnection, leading to a heat kernel regularization of traces. The obtained formula is a bivariant generalization of the JLO cocycle. Received: 26 November 2001 / Accepted: 22 February 2002?Published online: 2 October 2002