Anomaly and superconnection The Bargmann representation, generalized Dirac operators and the index of pseudodifferential operators on J. High Energy Phys
Hayato Kanno (Center for Gravitational Physics, Yukawa Institute for Theoretical Physics, Kyoto University, , Kyoto 606-8502, , Japan); Shigeki Sugimoto (Center for Gravitational Physics, Yukawa Institute for Theoretical Physics, Kyoto University, , Kyoto 606-8502, , Japan, Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo, , Kashiwanoha, Kashiwa 277-8583, , Japan)
Abstract We study anomalies of fermions with spacetime-dependent mass. Using Fujikawa’s method, it is found that the anomalies associated with the U(N)$_{+}$ × U(N)$_{−}$ chiral symmetry and U(N) flavor symmetry for even and odd dimensions, respectively, can be written in terms of superconnections. In particular, the anomaly for a vector-like U(1) symmetry is given by the Chern character of the superconnection in both even- and odd-dimensional cases. It is also argued that the non-Abelian anomaly for a system in D-dimensional spacetime is characterized by a (D + 2)-form part of the Chern character of the superconnection which generalizes the usual anomaly polynomial for the massless case. These results enable us to analyze anomalies in the systems with interfaces and spacetime boundaries in a unified way. Applications to index theorems, including the Atiyah–Patodi–Singer index theorem and a Callias-type index theorem, are also discussed. In addition, we give a natural string theory interpretation of these results.
