Spinor Bose-Einstein condensation and Bose ferromagnetism

Qiang Gu

Institute of Laser Physics, Hamburg University, Luruper Chaussee 149, 22761 Hamburg, Germany

The achievement in cooling alkali atomic gases, such as 87Rb, 23Na and 7Li, to quantum degeneracy opens up a way to study magnetism in spinor bosons, because these constituent atoms usually have a hyperfine spin degree of freedom. I will discuss ferromagnetism in spinor gases from a theoretical perspective. Some basic problems, including possible origins of the ferromagnetic interaction, the ferromagnetic transition and Bose-Einstein condensation, and the low-lying collective excitations of the spinor condensate, are condidered.