Collective excitations of a degenerate gas at the BEC-BCS crossover
Collective excitations of a degenerate gas at the BEC-BCS crossover
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DOI：
10.1103/physrevlett.92.203201
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发表时间：
2004-05-21
影响因子：
8.6
通讯作者：
Grimm, R
中科院分区：
文献类型：
--
作者：
Bartenstein, M;Altmeyer, A;Grimm, R
本文研究了Li-6原子费米气体在BEC-BCS交叉区的集体激发模。虽然在雪茄形阱中接近Feshbach共振的轴向压缩模式的测量证实了理论预期，但径向压缩模式显示出令人惊讶的特征。在强相互作用的分子BEC制度，我们观察到一个负的频率偏移与耦合强度的增加。在一个强烈相互作用的费米气体的制度，集体激发频率的突然变化发生，这可能是一个签名从超流过渡到无碰撞阶段。
We study collective excitation modes of a fermionic gas of Li-6 atoms in the BEC-BCS crossover regime. While measurements of the axial compression mode in the cigar-shaped trap close to a Feshbach resonance confirm theoretical expectations, the radial compression mode shows surprising features. In the strongly interacting molecular BEC regime, we observe a negative frequency shift with increasing coupling strength. In the regime of a strongly interacting Fermi gas, an abrupt change in the collective excitation frequency occurs, which may be a signature for a transition from a superfluid to a collisionless phase.