title: Anomalous discrete symmetries in three dimensions and group cohomology.
abstract: We study 't Hooft anomalies for a global discrete internal symmetry G. We construct examples of bosonic field theories in three dimensions with a nonvanishing 't Hooft anomaly for a discrete global symmetry. We also construct field theories in three dimensions with a global discrete internal symmetry G(1) × G(2) such that gauging G(1) necessarily breaks G(2) and vice versa. This is analogous to the Adler-Bell-Jackiw axial anomaly in four dimensions and parity anomaly in three dimensions.
authors: California Institute of Technology, Pasadena, California 91125, USA.
authors: Anton
authors: A
authors: Kapustin
authors: University of California, Berkeley, California 94720, USA.
authors: Ryan
authors: R
authors: Thorngren