Acoustic attenuation probe for Fermion superfluidity in ultracold-atom gases.
Dilute gas Bose-Einstein condensates (BEC's), currently used to cool fermionic atoms in atom traps, can also probe the superfluidity of these fermions. The damping rate of BEC-acoustic excitations (phonon modes), measured in the middle of the trap as a function of the phonon momentum, yields an unambiguous signature of BCS-like superfluidity, provides a measurement of the superfluid gap parameter, and gives an estimate of the size of the Cooper pairs in the BEC-BCS crossover regime. We also predict kinks in the momentum dependence of the damping rate which can reveal detailed information about the fermion quasiparticle dispersion relation.
Gaudio
Sergio
S
Department of Physics, Boston College, Chestnut Hill, Massachusetts 02167, USA. sergio.gaudio@roma1.infn.it
Mihaila
Bogdan
B
Blagoev
Krastan B
KB
Bedell
Kevin S
KS
Timmermans
Eddy
E