Spin-gap phenomenon in a strongly interacting ultracold Fermi gas
Spin-gap phenomenon in a strongly interacting ultracold Fermi gas
复制标题
DOI：
10.1088/1742-6596/568/1/012019
复制
发表时间：
2014
期刊：
影响因子：
--
通讯作者：
H. Tajima;R. Hanai;Y. Ohashi
中科院分区：
文献类型：
--
作者：
H. Tajima;R. Hanai;Y. Ohashi
我们研究了强相互作用的超冷费米气体的磁性。在扩展t矩阵近似的框架内，我们计算了在统一极限下的自旋磁化率χ。我们表明，在正常状态和超流体阶段，配对波动对该磁量的影响是完全不同的。在正常状态下，配对波动在超流体相变温度Tc附近引起自旋间隙现象，其中χ异常抑制。另一方面，在超流体相中，配对涨落削弱了BCS能隙对χ的普通抑制，因为它们在间隙内诱导了有限密度的态。我们的研究结果表明，自旋磁化率是研究超冷费米气体BCS-BEC交叉态中对涨落的一个有用的量。
We investigate magnetic properties of a strongly interacting ultracold Fermi gas. Within the framework of an extended T-matrix approximation, we calculate the spin susceptibility χ in the unitarity limit. We show that effects of pairing fluctuations on this magnetic quantity are quite different in between the normal state and the superfluid phase. In the normal state, pairing fluctuations cause spin-gap phenomenon near the superfluid phase transition temperature Tc, where χ is anomalously suppressed. In the superfluid phase, on the other hand, the ordinary suppression of χ by the BCS energy gap is weakened by pairing fluctuations, because they induce finite density of states inside the gap. Our results indicate that the spin susceptibility is a useful quantity for the study of pairing fluctuations in the BCS-BEC crossover regime of an ultracold Fermi gas.