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arXiv · 1112.5977

Realization of a Resonant Fermi Gas with a Large Effective Range

E. L. Hazlett·Y. Zhang·R. W. Stites·K. M. O'Hara
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Abstract

We have measured the interaction energy and three-body recombination rate for a two-component Fermi gas near a narrow Feshbach resonance and found both to be strongly energy dependent. Even for deBroglie wavelengths greatly exceeding the van der Waals length scale, the behavior of the interaction energy as a function of temperature cannot be described by atoms interacting via a contact potential. Rather, energy-dependent corrections beyond the scattering length approximation are required, indicating a resonance with an anomalously large effective range. For fields where the molecular state is above threshold, the rate of three-body recombination is enhanced by a sharp, two-body resonance arising from the closed-channel molecular state which can be magnetically tuned through the continuum. This narrow resonance can be used to study strongly correlated Fermi gases that simultaneously have a sizeable effective range and a large scattering length.

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E. L. Hazlett, Y. Zhang, R. W. Stites, K. M. O'Hara. 2011-12-27. Realization of a Resonant Fermi Gas with a Large Effective Range. https://doi.org/10.1103/physrevlett.108.045304

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