Spin-1 bosons with coupled ground states in optical lattices
- Fachbereich Physik der Universitaet Duisburg-Essen, Campus Essen, Universitaetsstr. 5, D-45117 Essen (Germany)
The superfluid-Mott-insulator phase transition of ultracold spin-1 bosons with ferromagnetic and antiferromagnetic interactions in an optical lattice is theoretically investigated. Two counterpropagating linearly polarized laser beams with the angle {theta} between the polarization vectors (lin-{theta}-lin configuration), driving an F{sub g}=1 to F{sub e}=1 internal atomic transition, create the optical lattice and at the same time couple atomic ground states with magnetic quantum numbers m={+-}1. Due to the coupling the system can be described as a two-component one. At {theta}=0 the system has a continuous isospin symmetry, which can be spontaneously broken, thereby fixing the number of particles in the atomic components. The phase diagram of the system and the spectrum of collective excitations, which are density waves and isospin waves, are worked out. In the case of ferromagnetic interactions, the superfluid-Mott-insulator phase transition is always second order, but in the case of antiferromagnetic interactions for some values of system parameters it is first order and the superfluid and Mott phases can coexist. Varying the angle {theta} one can control the populations of atomic components and continuously turn on and tune their asymmetry.
- OSTI ID:
- 20649980
- Journal Information:
- Physical Review. A, Vol. 70, Issue 6; Other Information: DOI: 10.1103/PhysRevA.70.063610; (c) 2004 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ANTIFERROMAGNETISM
ASYMMETRY
ATOMS
BASIC INTERACTIONS
BOSONS
COLLECTIVE EXCITATIONS
CONTROL
COUPLING
EXCITED STATES
GROUND STATES
ISOSPIN
LASER RADIATION
OPTICS
PHASE DIAGRAMS
PHASE TRANSFORMATIONS
PHOTON-ATOM COLLISIONS
POLARIZATION
QUANTUM NUMBERS
RUBIDIUM
SPIN
SUPERFLUIDITY
SYMMETRY
SYMMETRY BREAKING