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B. Battelier, M. Cheneau, S. Stock, Z. Hadzibabic and J. Dalibard
New physics is expected to appear in low-dimensional gases. In homogeneous 2D systems, a true Bose-Einstein condensate can exist only at zero temperature, while the finite temperature Kosterlitz-Thouless transition to superfluidity results in a phase-fluctuating quasi-condensate with no long range order. So far, the properties of trapped 2D atomic gases [1] have been explored mostly theoretically because of the difficulty to produce and study these systems experimentally [2-4]. We apply a 1D optical lattice along a cigar-shaped 3D BEC so that we get 30 independent quasi-2D condensates [5]. Using a radiofrequency field, we can address each condensate individually and we can isolate either a single or a few equally spaced BECs. To study their phase-coherence properties, we let interfere two to eight condensates. We observe interference patterns which clearly reveal the presence of phase defects in these systems. [1] D. S. Petrov, M. Holzmann, and G.V. Shlyapnikov, Phys. Rev. Lett. 84, 2551 (2000) [2] A. Görlitz et al., Phys. Rev. Lett. 87, 130402 (2001) [3] D. Rychtarik et al., Phys. Rev. Lett. 82, 173003 (2004) [4] N. L. Smith et al., Journal of Physics B 38, 223 (2005) [5] Z. Hadzibabic et al., Phys. Rev. Lett. 93, 180403 (2004) |
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