Ultracold chromium atoms: from Feshbach resonances to a dipolar Bose–Einstein condensate
| Autor: | Jürgen Stuhler, T. Koch, Marco Fattori, Axel Griesmaier, Jörg Werner, Tilman Pfau |
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| Rok vydání: | 2007 |
| Předmět: | |
| Zdroj: | Journal of Modern Optics. 54:647-660 |
| ISSN: | 1362-3044 0950-0340 |
| DOI: | 10.1080/09500340600677088 |
| Popis: | We report on experiments with ultracold chromium atoms. Preparing a cloud of 52Cr atoms in a crossed optical dipole trap (CODT) and applying magnetic fields between 4 and 600 G, we observe 14 Feshbach resonances by the occurrence of increased atom loss at distinct magnetic field values. A comparison with theory taking only dipole–dipole coupling into account shows very good agreement between experimental and theoretical resonance positions and allows us to extract the s-wave scattering lengths a 6=112(14) a 0, a 4= 58(6) a 0, a 2=−7(20) a 0 of the involved molecular potentials as well as the dispersion coefficients C 6= 733(70) au and au. The strongest resonance at 589 G has a calculated width of 1.7 G and reveals a three-body loss coefficient below L 3, max∼3×10−36 m6 s−1. Further evaporative cooling within the CODT leads to the formation of a Bose–Einstein condensate (BEC) with up to 100 000 condensed atoms. The magnetic dipole–dipole interaction between the Cr atoms is so strong that, as a first mecha... |
| Databáze: | OpenAIRE |
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