Abstract
We study spectral triples over noncommutative principal U(1) bundles. Basing on the classical situation and the abstract algebraic approach, we propose an operatorial definition for a connection and compatibility between the connection and the Dirac operator on the total space and on the base space of the bundle. We analyze in details the example of the noncommutative three-torus viewed as a U(1) bundle over the noncommutative two-torus and find all connections compatible with an admissible Dirac operator. Conversely, we find a family of new Dirac operators on the noncommutative tori, which arise from the base-space Dirac operator and a suitable connection.
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Communicated by A. Connes
Partially supported by GSQS 230836 (IRSES, EU) and PRIN 2010-2012 (MIUR, Italy).
Partially supported by MNII grants 189/6.PRUE/2007/7 and N 201 1770 33.
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Dąbrowski, L., Sitarz, A. Noncommutative Circle Bundles and New Dirac Operators. Commun. Math. Phys. 318, 111–130 (2013). https://doi.org/10.1007/s00220-012-1550-8
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DOI: https://doi.org/10.1007/s00220-012-1550-8