Gupta, S; Hadzibabic, Z; Zwierlein, M W; Stan, C A; Dieckmann, K; Schunck, C H; E G M van Kempen; Verhaar, B J; Ketterle, W
arXiv.org,
07/2003
Paper
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.
