Global 4-group symmetry and ’t Hooft anomalies in topological axion electrodynamics

Global symmetries and ’t Hooft anomalies in brane tilings

We investigate the relation between gauge theories and brane configurations described by brane tilings. We identify U(1)B (baryonic), U(1)M (mesonic), and U(1)R global symmetries in gauge theories with gauge symmetries in the brane configurations. We also show that U(1)MU(1) 2 B and U(1)RU(1) 2 B ’t Hooft anomalies are reproduced as gauge transformations of the classical brane action. ∗E-mail: ...

Symmetry Protected Topological Phases, Anomalies, and Cobordisms: Beyond Group Cohomology

We propose that Symmetry Protected Topological Phases with a finite symmetry group G are classified by cobordism groups of the classifying space of G. This provides an explanation for the recent discovery of bosonic SPT phases which do not fit into the group cohomology classification. We discuss the connection of the cobordism classification of SPT phases to gauge and gravitational anomalies in...

Wave propagation in axion electrodynamics

In this paper, the axion contribution to the electromagnetic wave propagation is studied. First we show how the axion electrodynamics model can be embedded into a premetric formalism of Maxwell electrodynamics. In this formalism, the axion field is not an arbitrary added Chern-Simon term of the Lagrangian, but emerges in a natural way as an irreducible part of a general constitutive tensor. We ...

Symmetry breaking induced by ’t Hooft non-abelian flux

We analyze a SU(N) gauge theory on M4 × T . We find and catalogue all possible degenerate zero-energy stable configurations in the case of trivial or non-trivial ’t Hooft non abelian flux. We describe the residual symmetries of each vacua and the 4-dimensional effective spectrum in terms of continous and discrete parameters, respectively.

Symmetry in Electrodynamics