Pseudogap phenomenon in an ultracold Fermi gas with a p-wave pairing interaction
Pseudogap phenomenon in an ultracold Fermi gas with a p-wave pairing interaction
复制标题
DOI：
10.1103/physreva.85.053628
复制
发表时间：
2012-05
影响因子：
2.9
通讯作者：
D. Inotani;R. Watanabe;M. Sigrist;Y. Ohashi
中科院分区：
文献类型：
--
作者：
D. Inotani;R. Watanabe;M. Sigrist;Y. Ohashi
我们研究了具有可调谐相互作用的单组分费米气体的单粒子性质。将与这种各向异性相互作用相关的成对涨落包括在a矩阵理论中，我们计算了超流体转变温度以上的单粒子态密度和谱权重。从弱耦合区域出发，我们证明了随着相互作用强度的增加，所谓的赝隙首先在这些量中发展。然而，当相互作用变强到一定程度时，伪隙变得模糊，最终消失在中间耦合区域。在强耦合区域，与形成紧密结合分子相关的激发能隙再次打开。这种非单调相互作用对激发能隙的依赖关系与a波相互作用的情况截然不同，在这种情况下，赝能隙只是随着相互作用强度的增加而发展，不断地转变为分子激发能隙。结果表明，这两种情况之间的差异源于波相互作用的动量依赖性，这种依赖性在低动量极限下消失。我们还在相图中确定了与温度和波相互作用强度有关的赝隙区域。由于赝隙是超流相变的前兆现象，我们的结果将对实现波超流费米气体的研究有帮助。
We investigate single-particle properties of a one-component Fermi gas with a tunable-wave interaction. Including pairing fluctuations associated with this anisotropic interaction within a-matrix theory, we calculate the single-particle density of states, as well as the spectral weight, above the superfluid transition temperature. Starting from the weak-coupling regime, we show that the so-called pseudogap first develops in these quantities with increasing the interaction strength. However, when the interaction becomes strong to some extent, the pseudogap becomes obscure to eventually disappear in the intermediate coupling regime. In the strong-coupling regime, the excitation gap associated with the formation of tightly bound molecules again opens. This nonmonotonic interaction dependence of the excitation gap is quite different from the case of an-wave interaction, where the pseudogap simply develops with increasing the interaction strength, which continuously changes into the molecular excitation gap. The difference between the two cases is shown to originate from the momentum dependence of the-wave interaction, which vanishes in the low momentum limit. We also identify the pseudogap regime in the phase diagram with respect to the temperature and the-wave interaction strength. Since the pseudogap is a precursor phenomenon of the superfluid phase transition, our results would be useful for the research toward the realization of-wave superfluid Fermi gases.