Gaudio Sergio, Mihaila Bogdan, Blagoev Krastan B, Bedell Kevin S, Timmermans Eddy
Department of Physics, Boston College, Chestnut Hill, Massachusetts 02167, USA.
Phys Rev Lett. 2007 Mar 16;98(11):110407. doi: 10.1103/PhysRevLett.98.110407. Epub 2007 Mar 15.
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.
稀薄气体玻色-爱因斯坦凝聚体（BEC）目前用于冷却原子阱中的费米子原子，它也可以探测这些费米子的超流性。在阱中心测量的BEC声子激发（声子模式）的阻尼率作为声子动量的函数，产生了BCS类超流性的明确特征，提供了超流能隙参数的测量，并给出了BEC-BCS交叉区域中库珀对大小的估计。我们还预测了阻尼率动量依赖性中的扭折，这可以揭示有关费米子准粒子色散关系的详细信息。
