1998/03/13 by Tetsuo Ohmi, Kazushige Machida
Physics and Astronomy · #cond-mat
paper · pdf · doi:10.1143/jpsj.67.1822
published as J. Phys. Soc. Jpn. 67, 1822 (1998). · 4 pages, 1 eps figure
arxiv created 1998/03/13 · arxiv updated 2009/11/30
The Bogoliubov theory is extended to a Bose-Einstein condensation with internal degrees of freedom, realized recently in 23Na gases where several hyperfine states are simultaneously cooled optically. Starting with a Hamiltonian constructed from general gauge and spin rotation symmetry principles fundamental equations for condensate are derived. The ground state where time reversal symmetry is broken in some case and low-lying collective modes, e.g. spin and density wave modes, are discussed. Novel vortex as a topological defect can be created experimentally.