Instantons in four-dimensional gauged O(5) Skyrme models

摘要

We consider a family of four-dimensional nonlinear sigma models based on an O(5) symmetric group, whose fields take their values on the 4-sphere S-4. An SO(4)-subgroup of the model is gauged. The solutions of the model are characterized by two distinct topological charges, the Chern-Pontryagin charge of the gauge field and the degree of the map, i.e., the winding number, of the S-4 field. The one-dimensional equations arising from the variation of the action density subjected to spherical symmetry are integrated numerically. Several properties of the solutions thus constructed are pointed out. The only solution with unit Chern-Pontryagin charge are the usual BPST instantons with zero S-4 winding number, while solutions with unit S-4 winding number have zero Chern-Pontryagin charge. (C) 2001 American Institute of Physics. [References: 19]