Sascha Hoinka, Marcus Lingham, Kristian Fenech, Hui Hu, Chris J. Vale, Joaquín E. Drut, Stefano Gandolfi
We present a high-precision determination of the universal contact parameter in strongly interacting Fermi gases. The contact governs the high-momentum properties (i.e. the short-range correlations) of these systems. The experimental measurement utilises Bragg spectroscopy to obtain the dynamic and static structure factors of ultracold Fermi gases at high momentum in the unitarity and molecular Bose-Einstein condensate (BEC) regimes. We have also performed quantum Monte Carlo calculations of the static properties, extending from the weakly coupled Bardeen-Cooper-Schrieffer (BCS) regime to the strongly coupled BEC case, which show excellent agreement with experiment at the level of a few percent. At unitarity our low temperature measurement provides a new benchmark for the zero temperature homogeneous contact which we find to be $3.33 \pm 0.07$.
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http://arxiv.org/abs/1209.3830
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