Monopoles in an antiferromagnetic Bose-Einstein condensate.

We show that even in three dimensions an antiferromagnetic spin-1 Bose-Einstein condensate, which can, for instance, be created with (23)Na atoms in an optical trap, has not only singular linelike vortex excitations, but also allows for singular pointlike topological excitations, i.e., monopoles similar to the 't Hooft-Polyakov monopoles. We discuss the static and dynamic properties of these monopoles.