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A: Fachverband Atomphysik
A 1: Quantengase (jointly with Q)
A 1.2: Talk
Monday, March 19, 2007, 10:45–11:00, 6J
Comparing Contact and Dipolar Interactions in a Bose-Einstein Condensate — •Axel Griesmaier, Jürgen Stuhler, Tobias Koch, Marco Fattori, Stefano Giovanazzi, and Tilman Pfau — 5. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart, Germany
We have measured the relative strength εdd of the magnetic dipole-dipole interaction compared with the contact interaction [1] in a dipolar chromium Bose-Einstein condensate [2]. We analyze the asymptotic velocities of expansion of the condensate with different orientations of the atomic magnetic moments. By comparing the experimental results with numerical solutions of the hydrodynamic equations for dipolar condensates, we obtain εdd=0.159±0.034. We use this result to determine the s-wave scattering length a=(5.08±1.06) 10−9m=(96±20) a0 of 52Cr. This is fully consistent with our previous measurements on the basis of Feshbach resonances [3] and therefore confirms the validity of the theoretical approach used to describe the dipolar Bose-Einstein condensate.
[1] A. Griesmaier et al., Phys. Rev. Lett. in press (2006).
[2] A. Griesmaier et al., Phys. Rev. Lett. 94, 160401 (2005).
[3] J. Werner et al., Phys. Rev. Lett. 94, 183201 (2005).