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R. Chicireanu, A. Pouderous, B. Laburthe-Tolra, E. Maréchal, L. Vernac, J. C. Keller, and O. Gorceix.
We will present new experimental results on the simultaneous magneto-optical trapping of Fermionic 53Cr and Bosonic 52Cr. Both isotopes are produced in a high temperature oven operating at 1500 °C, and slowed in a Zeeman slower before being captured in a Magneto-Optical Trap (MOT). We measured loading rates up to 108 s-1 for 52Cr atoms and up to 5.106s-1 for 53Cr atoms. We measured the MOT inelastic loss rate coefficients for both isotopes and found, in accordance with previous results for 52Cr, very large inelastic loss parameters. Those are orders of magnitude larger than those measured for any other atom in a MOT (with the exception of Sr, whose inelastic coefficient is "only" five times smaller than for chromium). Our theoretical analysis points towards an unusual long range loss mechanism, which we will discuss. We also studied inelastic losses when 53Cr and 52Cr are simultaneously trapped in the MOT. Preliminary results show no significant inter-isotope collisionnal losses. We also showed that both 53Cr and 52Cr atoms spontaneously populate by radiative decay metastable dark states, which are trapped by the MOT magnetic field gradient. We will discuss the prospects to accumulate large numbers of chromium atoms in a magnetic trap, and will describe our strategy for evaporative cooling down to quantum degeneracy. Our long term scientific goals include the study of the effect of dipole-dipole interaction on quantum degenerate Bose and Fermi gases and the transfer of these gases into optical lattices. |
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