We study Berry’s connection potentials of many-body ground states of spin-one bosons with antiferromagnetic interactions in adiabatically varying magnetic fields. We find that Berry’s connection potentials are generally determined by, instead of usual singular monopoles, linearly positioned monosegments each of which carries one unit of topological charge; in the absence of a magnetic field gradient this distribution of monosegments becomes a linear chain of monopoles. Consequently, Berry’s phases consist of a series of step functions of magnetic fields; a magnetic field gradient causes rounding of these step functions. We also calculate Berry’s connection fields, profiles of monosegments, and show that the total topological charge is conserved in a parameter space.

• Received 5 November 2003

DOI:https://doi.org/10.1103/PhysRevB.70.115110