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Localization of bosonic atoms by fermionic impurities in a 3d optical lattice

S. Ospelkaus·C. Ospelkaus·O. Wille·M. Succo·P. Ernst·K. Sengstock·K. Bongs
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Abstract

We observe a localized phase of ultracold bosonic quantum gases in a 3-dimensional optical lattice induced by a small contribution of fermionic atoms acting as impurities in a Fermi-Bose quantum gas mixture. In particular we study the dependence of this transition on the fermionic 40K impurity concentration by a comparison to the corresponding superfluid to Mott insulator transition in a pure bosonic 87Rb gas and find a significant shift in the transition parameter. The observed shift is larger than expected based on a mean-field argument, which is a strong indication that disorder-related effects play a significant role.

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S. Ospelkaus, C. Ospelkaus, O. Wille, M. Succo, P. Ernst, K. Sengstock, K. Bongs. 2006-04-06. Localization of bosonic atoms by fermionic impurities in a 3d optical lattice. https://doi.org/10.1103/physrevlett.96.180403

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