2000 character limit reached
Higher-form symmetries and 3-group in axion electrodynamics (2006.12532v3)
Published 22 Jun 2020 in hep-th, cond-mat.str-el, and hep-ph
Abstract: We study higher-form symmetries in a low-energy effective theory of a massless axion coupled with a photon in $(3+1)$ dimensions. It is shown that the higher-form symmetries of this system are accompanied by a semistrict 3-group (2-crossed module) structure, which can be found by the correlation functions of symmetry generators of the higher-form symmetries. We argue that the Witten effect and anomalous Hall effect in the axion electrodynamics can be described in terms of 3-group transformations.