title: Non-Abelian magnetic monopole in a Bose-Einstein condensate.
abstract: Recently, an effective non-Abelian magnetic field with a topology of a monopole was shown to emerge from the adiabatic motion of multilevel atoms in spatially varying laser fields [J. Ruseckas, Phys. Rev. Lett. 95, 010404 (2005)10.1103/PhysRevLett.95.010404]. We study this monopole in a Bose-Einstein condensate of degenerate dressed states and find that the topological charge of the pseudospin cancels the monopole charge resulting in a vanishing gauge invariant charge. As a function of the laser wavelength, different stationary states are classified in terms of their effect to the monopole part of the magnetic field and a crossover to vortex ground state is observed.
authors.affiliation: Department of Applied Physics/COMP, Helsinki University of Technology, P.O. Box 5100, FI-02015 TKK, Finland.
authors.forename: Ville
authors.initials: V
authors.lastname: Pietilä
authors.forename: Mikko
authors.initials: M
authors.lastname: Möttönen