Wednesday, October 17, 2012

1210.4302 (Ezio Vasselli)

Presheaves of symmetric tensor categories and nets of C*-algebras    [PDF]

Ezio Vasselli
Motivated by algebraic quantum field theory, we study presheaves of symmetric tensor categories defined on the base of a space, intended as a spacetime. Any section of a presheaf (that is, any "superselection sector", in the applications that we have in mind) defines a holonomy representation whose triviality is measured by Cheeger-Chern-Simons characteristic classes, and a non-abelian unitary cocycle defining a Lie group gerbe. We show that, provided an embedding in a presheaf of full subcategories of the one of Hilbert spaces, the section category of a presheaf is a Tannaka-type dual of a locally constant group bundle (the "gauge group"), which may not exist and in general is not unique. This leads to the notion of gerbe of C*-algebras, defined on the given base.
View original: http://arxiv.org/abs/1210.4302

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