Magnetism of Bose gases

The magnetism of Fermi gases and local magnetic moments has long been a key research topic in condensed matter physics, while that of Bose gases has historically been less studied. The reason for this may be due to the fact that He-4, the prototypical Bose system studied in earlier years, is a system of scalar particles and does not display magnetism at all. The realization of Bose-Einstein condensation in alkali atoms opens up a way to study magnetism in spinor bosons, because these constituent atoms usually have a hyperfine spin degree of freedom. This paper will review our current understanding of magnetism in Bose gases, especially focusing on new results obtained regarding ferromagnetic transitions in spinor bosons and the spin dynamics of spinor condensates.