Pseudogap phenomena in a two-dimensional ultracold Fermi gas near the Berezinskii-Kosterlitz-Thouless transition
Pseudogap phenomena in a two-dimensional ultracold Fermi gas near the Berezinskii-Kosterlitz-Thouless transition
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Berezinskii-Kosterlitz-Thouless 转变附近二维超冷费米气体中的赝能隙现象
DOI：
10.1088/1742-6596/568/1/012012
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
and Y. Ohashi
中科院分区：
文献类型：
--
作者：
M. Matsumoto;and Y. Ohashi
我们研究二维费米气体中的单粒子激发和强耦合效应。包括高斯涨落理论中的配对涨落，我们计算了 Berezinskii-Kosterlitz-Thouless (BKT) 转变温度 T BKT 附近的态密度 ρ (ω)。在 T BKT 附近，我们发现超流体涨落会引起 ρ (ω) 中的赝能隙。尽管在当前的二维情况下不存在超流序参数，但赝能隙结构与 BCS 超流态密度非常相似。由于最近实现了二维 40 K 费米气体，我们的结果将有助于理解 BKT 不稳定性附近的单粒子特性。
We investigate single-particle excitations and strong-coupling effects in a twodimensional Fermi gas. Including pairing fluctuations within a Gaussian fluctuation theory, we calculate the density of states ρ (ω) near the Berezinskii-Kosterlitz-Thouless (BKT) transition temperature T BKT. Near T BKT, we show that superfluid fluctuations induce a pseudogap in ρ (ω). The pseudogap structure is very similar to the BCS superfluid density of states, although the superfluid order parameter is absent in the present two-dimensional case. Since a twodimensional 40 K Fermi gas has recently been realized, our results would contribute to the understanding of single-particle properties near the BKT instability.