title: Effective geometric phases and topological transitions in SO(3) and SU(2) rotations.
abstract: We address the development of geometric phases in classical and quantum magnetic moments (spin-1/2) precessing in an external magnetic field. We show that nonadiabatic dynamics lead to a topological phase transition determined by a change in the driving field topology. The transition is associated with an effective geometric phase which is identified from the paths of the magnetic moments in a spherical geometry. The topological transition presents close similarities between SO(3) and SU(2) cases but features differences in, e.g. the adiabatic limits of the geometric phases, being 2π and π in the classical and the quantum case, respectively. We discuss possible experiments where the effective geometric phase would be observable.
authors.affiliation: RIKEN Center for Emergent Matter Science (CEMS), Saitama 351-0198, Japan.
authors.forename: Henri
authors.initials: H
authors.lastname: Saarikoski
authors.forename: José Pablo
authors.initials: JP
authors.lastname: Baltanás
authors.forename: J Enrique
authors.initials: JE
authors.lastname: Vázquez-Lozano
authors.forename: Junsaku
authors.initials: J
authors.lastname: Nitta
authors.forename: Diego
authors.initials: D
authors.lastname: Frustaglia