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Observation of Dipole-Induced Spin Texture in an $^{87}$Rb Bose-Einstein Condensate

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 Added by Yujiro Eto
 Publication date 2014
  fields Physics
and research's language is English




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We report the spin texture formation resulting from the magnetic dipole-dipole interaction in a spin-2 $^{87}$Rb Bose-Einstein condensate. The spinor condensate is prepared in the transversely polarized spin state and the time evolution is observed under a magnetic field of 90 mG with a gradient of 3 mG/cm using Stern-Gerlach imaging. The experimental results are compared with numerical simulations of the Gross-Pitaevskii equation, which reveals that the observed spatial modulation of the longitudinal magnetization is due to the spin precession in an effective magnetic field produced by the dipole-dipole interaction. These results show that the dipole-dipole interaction has considerable effects even on spinor condensates of alkali metal atoms.



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We demonstrate a production of large-area $^{87}$Rb Bose-Einstein condensates (BECs) using a non-Gaussian optical dipole trap (ODT). The ODT is formed by focusing a symmetrically truncated Gaussian laser beam and it is shown that the beam clipping causes the trap geometry elongated and flattened along the beam axis direction. In the clipped-Gaussian ODT, an elongated, highly oblate BEC of $^{87}$Rb is generated with length and width of approximately $470~mutextrm{m}$ and $130~mutextrm{m}$, respectively, where the condensate healing length is estimated to be $xiapprox 0.25~mutextrm{m}$ at the trap center. The ODT is characterized to have a quartic trapping potential along the beam axis and the atom density of the condensate is uniform within 10% over $1000xi$ in the central region. Finally, we discuss the prospect of conducting vortex shedding experiments using the elongated condensate.
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