Aug 4 – 7, 2020
Asia/Tokyo timezone

A physicist-friendly reformulation of the mod-two Atiyah-Patodi-Singer index

Aug 7, 2020, 4:20 PM


Theoretical Developments Theoretical Developments


Yoshiyuki Matsuki (*) (Osaka University)


Gauge anomaly in 4-dimensions can be viewed as a current inflow into an extra-dimension, where the total phase of the fermion partition function is given in a gauge invariant way by the Atiyah-Patodi-Singer(APS) eta-invariant of a 5-dimensional Dirac operator. However, this formalism requires a non-local boundary condition, which makes the physical roles of edge/bulk modes unclear and the causality of the total theory doubtful. In this talk, we consider a special case where the Dirac operator is in a real representation and its eta invariant becomes the mod-two type APS index. We propose a physicist-friendly reformulation of the mod-two index using domain-wall fermion formalism, which naturally describes how the global anomaly is canceled between edge and bulk.

Primary author

Yoshiyuki Matsuki (*) (Osaka University)


Presentation materials