KMS states on the C-algebras of Fell bundles over groupoids

Publication Name

Mathematical Proceedings of the Cambridge Philosophical Society

Abstract

We consider fibrewise singly generated Fell bundles over étale groupoids. Given a continuous real-valued 1-cocycle on the groupoid, there is a natural dynamics on the cross-sectional algebra of the Fell bundle. We study the Kubo-Martin-Schwinger equilibrium states for this dynamics. Following work of Neshveyev on equilibrium states on groupoid C∗-algebras, we describe the equilibrium states of the cross-sectional algebra in terms of measurable fields of states on the C∗-algebras of the restrictions of the Fell bundle to the isotropy subgroups of the groupoid. As a special case, we obtain a description of the trace space of the cross-sectional algebra. We apply our result to generalise Neshveyev's main theorem to twisted groupoid C∗-algebras, and then apply this to twisted C∗-algebras of strongly connected finite k-graphs.

Open Access Status

This publication is not available as open access

Volume

170

Issue

2

First Page

221

Last Page

246

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Link to publisher version (DOI)

http://dx.doi.org/10.1017/S0305004119000379