2-Group global symmetry in the compactified M2-brane

Abstract

We study generalized global symmetries of the bosonic M2-brane in eleven-dimensional backgrounds with non-trivial four-form flux. Focusing on compactifications of the form $AdS_5\times S^2_{1} \times S^2_{2}\times T^2$, we show that the monopole and winding symmetry sectors of the membrane do not organize as an ordinary direct product once the Wess--Zumino coupling is included. Instead, they combine into a non-trivial 2-group global symmetry. We identify the corresponding mixed background-gauge structure and show that the quantized target space flux determines the associated Postnikov class. This provides a concrete realization of higher-group symmetry in the worldvolume theory of the M2-brane induces a flux quantization on the worldvolume and relates its global symmetry structure to the introduction of a quantized flux in M-theory.