Gauge symmetries in the Heisenberg model of a magnet
Tadeusz Lulek
Abstract
A relation between geometric and gauge symmetries for the Heisenberg model of magnet is pointed out. The space of quantum states of the magnet exhibits the structure of a bundle, with the base consisting of nodes of the crystal, and the typical fiber spanned on the set of the single-node spin projections. The geometric symmetry group acts on the base, the gauge group — on the typical fiber, and all combined operations form the wreath product. In particular, all global gauge transformations yield the direct product group — a subgroup of the wreath product.