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Radio-Frequency Spectroscopy of Ultracold Fermions

S. Gupta·Z. Hadzibabic·M. W. Zwierlein·C. A. Stan·K. Dieckmann·C. H. Schunck·E. G. M. van Kempen·B. J. Verhaar·W. Ketterle
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Abstract

Radio-frequency techniques were used to study ultracold fermions. We observed the absence of mean-field "clock" shifts, the dominant source of systematic error in current atomic clocks based on bosonic atoms. This is a direct consequence of fermionic antisymmetry. Resonance shifts proportional to interaction strengths were observed in a three-level system. However, in the strongly interacting regime, these shifts became very small, reflecting the quantum unitarity limit and many-body effects. This insight into an interacting Fermi gas is relevant for the quest to observe superfluidity in this system.

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S. Gupta, Z. Hadzibabic, M. W. Zwierlein, C. A. Stan, K. Dieckmann, C. H. Schunck, E. G. M. van Kempen, B. J. Verhaar, W. Ketterle. 2003-07-10. Radio-Frequency Spectroscopy of Ultracold Fermions. https://doi.org/10.1126/science.1085335

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