Theoretical Paper Describes a new Phase Transition in an Ultra-Cold Gas

A group led by Pierre Meystre of the University of Arizona has showed new results of a calculation describing a gas of very cold atoms. In "Ferromagnetism in a lattice of Bose condensates" the authors show that an ensemble of spinor Bose-Einstein condensates confined in a one-dimensional optical lattice can undergo a ferromagnetic phase transition, and spontaneous magnetization arises due to the magnetic dipole-dipole interaction. This phenomenon is analogous to ferromagnetism in solid state physics, but in this case it occurs with bosons instead of fermions. The citation for this paper is Pu, H., Zhang, W., and Meystre, P., Physical Review Letters 87, 140405 (2001).