Local photoemission spectra and effects of spatial inhomogeneity in the BCS-BEC-crossover regime of a trapped ultracold Fermi gas
Local photoemission spectra and effects of spatial inhomogeneity in the BCS-BEC-crossover regime of a trapped ultracold Fermi gas
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DOI：
10.1103/physreva.95.053623
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发表时间：
2017-03
影响因子：
2.9
通讯作者：
Miki Ota;H. Tajima;R. Hanai;D. Inotani;Y. Ohashi
中科院分区：
文献类型：
--
作者：
Miki Ota;H. Tajima;R. Hanai;D. Inotani;Y. Ohashi
从理论上研究了超冷费米气体BCS(Bardeen-Cooper-Schrieffer)-BEC(玻色-爱因斯坦凝聚)交叉区中的单粒子激发。考虑到T矩阵近似下的强成对涨落，以及局域密度近似下的简谐陷阱势的影响，我们计算了正常态下的局域光电子能谱。最近，JILA小组在K费米气体中测量了这一量，以检验该系统的均匀单粒子性质。通过与实验结果的比较，我们发现，在JILA的实验条件下，这一尝试确实是成功的。然而，我们也发现，目前的局域光电子能谱仍有改进的空间，以检验在BCS-BEC交叉区预测的伪隙现象。由于超冷费米气体总是在陷阱中，我们的结果将有助于将该系统应用于各种均匀费米系统，作为量子模拟器。
We theoretically investigate single particle excitations in the BCS (Bardeen-Cooper-Schrieffer)-BEC (Bose-Einstein-Condensation) crossover regime of an ultracold Fermi gas. Including strong pairing fluctuations within a $T$-matrix approximation, as well as effects of a harmonic trap potential in the local density approximation, we calculate the local photoemission spectrum in the normal state. Recently, JILA group has measured this quantity in a $^{40}$K Fermi gas, in order to examine homogeneous single-particle properties of this system. Comparing our results with this experiment, we show that, this attempt indeed succeeds under the JILA's experimental condition. However, we also find that the current local photoemission spectroscopy still has room for improvement, in order to examine the pseudogap phenomenon predicted in the BCS-BEC crossover region. Since ultracold Fermi gases are always in a trap, our results would be useful in applying this system to various homogeneous Fermi systems, as a quantum simulator.