Radio-Frequency Spectroscopy of Ultracold Fermions

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 absence 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.

[1]  G. M. Stocks,et al.  The Interface Phase and the Schottky Barrier for a Crystalline Dielectric on Silicon , 2003, Science.

[2]  D. Pritchard,et al.  Sodium Bose-Einstein condensates in the F = 2 state in a large-volume optical trap. , 2002, Physical review letters.

[3]  W. Ketterle,et al.  Decay of an ultracold fermionic lithium gas near a Feshbach resonance , 2002, Postconference Digest Quantum Electronics and Laser Science, 2003. QELS..

[4]  M. Gehm,et al.  Observation of a Strongly Interacting Degenerate Fermi Gas of Atoms , 2002, Science.

[5]  E. Cornell,et al.  Effect of cold collisions on spin coherence and resonance shifts in a magnetically trapped ultracold gas , 2002, cond-mat/0208294.

[6]  M. Gehm,et al.  Measurement of the Zero Crossing in a Feshbach Resonance of Fermionic 6Li , 2002, cond-mat/0207717.

[7]  M. Inguscio,et al.  Fermi-Bose quantum degenerate 40K-87Rb mixture with attractive interaction. , 2002, Physical review letters.

[8]  Z Hadzibabic,et al.  Two-species mixture of quantum degenerate Bose and Fermi gases. , 2001, Physical review letters.

[9]  M. Gehm,et al.  All-optical production of a degenerate Fermi gas. , 2001, Physical review letters.

[10]  G. Ferrari,et al.  Quasipure Bose-Einstein condensate immersed in a Fermi sea. , 2001, Physical review letters.

[11]  R. Walser,et al.  Resonance superfluidity in a quantum degenerate Fermi gas. , 2001, Physical review letters.

[12]  A. Mann,et al.  Cold Atom Clocks , 2001 .

[13]  Randall G. Hulet,et al.  Observation of Fermi Pressure in a Gas of Trapped Atoms , 2001, Science.

[14]  H. Heiselberg.  Fermi systems with long scattering lengths , 2000, cond-mat/0002056.

[15]  Gibble,et al.  Measurement and cancellation of the cold collision frequency shift in an 87Rb fountain clock , 2000, Physical review letters.

[16]  D. Jin,et al.  Onset of fermi degeneracy in a trapped atomic Gas , 1999, Science.

[17]  D. Stamper-Kurn,et al.  BRAGG SPECTROSCOPY OF A BOSE-EINSTEIN CONDENSATE , 1999, cond-mat/9901109.

[18]  T. Esslinger,et al.  ATOM LASER WITH A CW OUTPUT COUPLER , 1998, cond-mat/9812258.

[19]  H. Stoof,et al.  Cooper-pair formation in trapped atomic Fermi gases , 1998, cond-mat/9804241.

[20]  D. Stamper-Kurn,et al.  Spin domains in ground-state Bose–Einstein condensates , 1998, Nature.

[21]  Dale G. Fried,et al.  Cold collision frequency shift of the 1S-2S transition in hydrogen , 1998, physics/9809016.

[22]  C. Wieman,et al.  Dynamical Response of a Bose-Einstein Condensate to a Discontinuous Change in Internal State , 1998, cond-mat/9803310.

[23]  R. Hulet,et al.  Elastic and inelastic collisions of 6Li atoms in magnetic and optical traps , 1997, cond-mat/9710333.

[24]  Dallin S. Durfee,et al.  Output Coupler for Bose-Einstein Condensed Atoms , 1997 .

[25]  Verhaar,et al.  Eliminating cold-collision frequency shifts. , 1995, Physical review. A, Atomic, molecular, and optical physics.

[26]  Chu,et al.  Laser-cooled Cs frequency standard and a measurement of the frequency shift due to ultracold collisions. , 1993, Physical review letters.

[27]  Pritchard,et al.  rf spectroscopy of trapped neutral atoms. , 1988, Physical Review Letters.