BEC文献3.pdfVIP

Bose-Einstein condensation with magnetic dipole-dipole forces Krzysztof G´oral†, Kazimierz Rz¸a˙zewski† and Tilman Pfau§♭ † Center for Theoretical Physics and College of Science, Polish Academy of Sciences, Aleja Lotnik´ow 32/46, 02-668 Warsaw, Poland § Faculty of Physics, University of Konstanz, 78457 Konstanz, Germany (February 1, 2008) netic trap by a buffer-gas technique [8] and by laser cool- Ground-state solutions in a dilute gas interacting via con- ing [9]. For these species the scattering lengths are not tact and magnetic dipole-dipole forces are investigated. To known to date, but, assuming a normal non-resonant be- the best of our knowledge, it is the first example of studies 0 havior, the crossections of the scalar contact potential 0 of the Bose-Einstein condensation in a system with realis- and the magnetic dipole–dipole interaction are of com- 0 tic long-range interactions. We find that for the magnetic parable size. 2 moment of e.g. chromium (6µB ) and a typical value of the As the dipole–dipole interaction is attractive parallel r scattering length all solutions are stable and only differ in a size from condensates without long-range interactions. By to a common polarization axis the immediate question arises: